Home / DTC / P1555 — Brake/Accelerate signal implausible

P1555 — Brake/Accelerate signal implausible

Detailed page for trouble code P1555.

34,405codes
59brands
11,914generic
22,491specific
Reset
Code

P1555

ALFA ROMEO P — Powertrain

Brake/Accelerate signal implausible

AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty brake light switch or brake pedal position sensor
  • Faulty accelerator pedal position (APP) sensor or throttle position sensor
  • Damaged wiring, corroded connectors or poor grounds in brake/APP circuits
  • Intermittent or failed CAN/serial communication between modules
  • Control module software fault or internal module failure
  • Incorrect sensor adjustment or mechanical binding in pedal assemblies

Symptoms

  • MIL/ABS/TC warning lamp illuminated
  • Cruise control disabled or faults stored
  • Engine reduced power/limp mode or unexpected torque limiting
  • Brake lights may be stuck ON or OFF
  • Inconsistent idle or sudden loss of engine response when braking/accelerating

What to check

  • Read freeze frame and stored data for P1555 and related codes
  • Inspect brake switch and accelerator pedal area for physical damage, binding or misadjustment
  • Scan live data: brake switch state, brake pedal position (if available), APP1/APP2 voltages and throttle actuator status
  • Check wiring harnesses and connector pins for corrosion, bent pins, water ingress or poor pin fit
  • Check for CAN bus communication errors and voltage supply to involved modules
  • Perform basic power/ground tests at sensors (battery voltage present, good ground)

Signal parameters

  • Brake switch: defined as ON/OFF; expected state = ON when pedal depressed, OFF when released (may be 0/5V or 0/12V depending on vehicle)
  • Accelerator pedal sensors (APP1/APP2): smooth, proportional voltages typically within ~0.5–4.5 V (manufacturer specific) and both channels must correlate
  • When brake is applied, APP voltage should be near idle (no significant acceleration request)
  • Typical implausibility rule: simultaneous high APP signal (wide open or above cruise threshold) and brake switch ON is invalid

Diagnostic algorithm

  1. Retrieve full DTC list and freeze frame, note engine speed, vehicle speed and pedal states at fault
  2. Clear codes and attempt to reproduce with a road or pedal test while monitoring live data
  3. Verify brake switch operation: physically actuate pedal while watching switch state; measure switch voltage/continuity with multimeter
  4. Verify APP sensors: compare APP1 and APP2 voltages while slowly depressing pedal — look for smooth, linear change and correlation between channels
  5. Inspect connectors and wiring continuity for brake switch and APP to the control modules; repair any damaged wiring or corrosion
  6. Check supply and ground at each sensor; confirm voltage reference (5V or 12V) is stable
  7. If CAN/communication faults present, check bus integrity, termination and module responses; repair or replace modules as needed
  8. If a specific sensor fails tests, replace the faulty component, clear codes and perform any required relearn/calibration procedures
  9. After repairs, confirm no reoccurrence of the code and perform a road test to verify normal operation

Likely causes

  • Brake switch stuck or mechanically misadjusted
  • APP sensor out of range or inconsistent dual sensor correlation
  • Damaged wiring or connector at brake switch or APP (short to power/ground)
  • Intermittent CAN bus errors between ABS/ECU and throttle modules

Fault status

⚠️ Status
Implausible brake-to-accelerator signal correlation detected — control module flagged inconsistent or out-of-range brake/accelerator inputs.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.5 hours

Similar codes

89

Browse 89 ALFA ROMEO manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

Your experience will help others
+100 karma for a short comment :)
Send to email
Code

P1555

BUICK P — Powertrain

Electronic Variable Orifice Output

Brand: BUICK
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty brake light switch or brake pedal position sensor
  • Faulty accelerator pedal position (APP) sensor or throttle position sensor
  • Damaged wiring, corroded connectors or poor grounds in brake/APP circuits
  • Intermittent or failed CAN/serial communication between modules
  • Control module software fault or internal module failure
  • Incorrect sensor adjustment or mechanical binding in pedal assemblies

Symptoms

  • MIL/ABS/TC warning lamp illuminated
  • Cruise control disabled or faults stored
  • Engine reduced power/limp mode or unexpected torque limiting
  • Brake lights may be stuck ON or OFF
  • Inconsistent idle or sudden loss of engine response when braking/accelerating

What to check

  • Read freeze frame and stored data for P1555 and related codes
  • Inspect brake switch and accelerator pedal area for physical damage, binding or misadjustment
  • Scan live data: brake switch state, brake pedal position (if available), APP1/APP2 voltages and throttle actuator status
  • Check wiring harnesses and connector pins for corrosion, bent pins, water ingress or poor pin fit
  • Check for CAN bus communication errors and voltage supply to involved modules
  • Perform basic power/ground tests at sensors (battery voltage present, good ground)

Signal parameters

  • Brake switch: defined as ON/OFF; expected state = ON when pedal depressed, OFF when released (may be 0/5V or 0/12V depending on vehicle)
  • Accelerator pedal sensors (APP1/APP2): smooth, proportional voltages typically within ~0.5–4.5 V (manufacturer specific) and both channels must correlate
  • When brake is applied, APP voltage should be near idle (no significant acceleration request)
  • Typical implausibility rule: simultaneous high APP signal (wide open or above cruise threshold) and brake switch ON is invalid

Diagnostic algorithm

  1. Retrieve full DTC list and freeze frame, note engine speed, vehicle speed and pedal states at fault
  2. Clear codes and attempt to reproduce with a road or pedal test while monitoring live data
  3. Verify brake switch operation: physically actuate pedal while watching switch state; measure switch voltage/continuity with multimeter
  4. Verify APP sensors: compare APP1 and APP2 voltages while slowly depressing pedal — look for smooth, linear change and correlation between channels
  5. Inspect connectors and wiring continuity for brake switch and APP to the control modules; repair any damaged wiring or corrosion
  6. Check supply and ground at each sensor; confirm voltage reference (5V or 12V) is stable
  7. If CAN/communication faults present, check bus integrity, termination and module responses; repair or replace modules as needed
  8. If a specific sensor fails tests, replace the faulty component, clear codes and perform any required relearn/calibration procedures
  9. After repairs, confirm no reoccurrence of the code and perform a road test to verify normal operation

Likely causes

  • Brake switch stuck or mechanically misadjusted
  • APP sensor out of range or inconsistent dual sensor correlation
  • Damaged wiring or connector at brake switch or APP (short to power/ground)
  • Intermittent CAN bus errors between ABS/ECU and throttle modules

Fault status

⚠️ Status
Implausible brake-to-accelerator signal correlation detected — control module flagged inconsistent or out-of-range brake/accelerator inputs.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.5 hours

Similar codes

Your experience will help others
+100 karma for a short comment :)
Send to email
Code

P1555

CADILLAC P — Powertrain

Electronic Variable Orifice Output

Brand: CADILLAC
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty brake light switch or brake pedal position sensor
  • Faulty accelerator pedal position (APP) sensor or throttle position sensor
  • Damaged wiring, corroded connectors or poor grounds in brake/APP circuits
  • Intermittent or failed CAN/serial communication between modules
  • Control module software fault or internal module failure
  • Incorrect sensor adjustment or mechanical binding in pedal assemblies

Symptoms

  • MIL/ABS/TC warning lamp illuminated
  • Cruise control disabled or faults stored
  • Engine reduced power/limp mode or unexpected torque limiting
  • Brake lights may be stuck ON or OFF
  • Inconsistent idle or sudden loss of engine response when braking/accelerating

What to check

  • Read freeze frame and stored data for P1555 and related codes
  • Inspect brake switch and accelerator pedal area for physical damage, binding or misadjustment
  • Scan live data: brake switch state, brake pedal position (if available), APP1/APP2 voltages and throttle actuator status
  • Check wiring harnesses and connector pins for corrosion, bent pins, water ingress or poor pin fit
  • Check for CAN bus communication errors and voltage supply to involved modules
  • Perform basic power/ground tests at sensors (battery voltage present, good ground)

Signal parameters

  • Brake switch: defined as ON/OFF; expected state = ON when pedal depressed, OFF when released (may be 0/5V or 0/12V depending on vehicle)
  • Accelerator pedal sensors (APP1/APP2): smooth, proportional voltages typically within ~0.5–4.5 V (manufacturer specific) and both channels must correlate
  • When brake is applied, APP voltage should be near idle (no significant acceleration request)
  • Typical implausibility rule: simultaneous high APP signal (wide open or above cruise threshold) and brake switch ON is invalid

Diagnostic algorithm

  1. Retrieve full DTC list and freeze frame, note engine speed, vehicle speed and pedal states at fault
  2. Clear codes and attempt to reproduce with a road or pedal test while monitoring live data
  3. Verify brake switch operation: physically actuate pedal while watching switch state; measure switch voltage/continuity with multimeter
  4. Verify APP sensors: compare APP1 and APP2 voltages while slowly depressing pedal — look for smooth, linear change and correlation between channels
  5. Inspect connectors and wiring continuity for brake switch and APP to the control modules; repair any damaged wiring or corrosion
  6. Check supply and ground at each sensor; confirm voltage reference (5V or 12V) is stable
  7. If CAN/communication faults present, check bus integrity, termination and module responses; repair or replace modules as needed
  8. If a specific sensor fails tests, replace the faulty component, clear codes and perform any required relearn/calibration procedures
  9. After repairs, confirm no reoccurrence of the code and perform a road test to verify normal operation

Likely causes

  • Brake switch stuck or mechanically misadjusted
  • APP sensor out of range or inconsistent dual sensor correlation
  • Damaged wiring or connector at brake switch or APP (short to power/ground)
  • Intermittent CAN bus errors between ABS/ECU and throttle modules

Fault status

⚠️ Status
Implausible brake-to-accelerator signal correlation detected — control module flagged inconsistent or out-of-range brake/accelerator inputs.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.5 hours

Similar codes

103

Browse 103 CADILLAC manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

CADILLAC

Your experience will help others
+100 karma for a short comment :)
Send to email
Code

P1555

CHEVROLET P — Powertrain

Electronic Variable Orifice Output

AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty brake light switch or brake pedal position sensor
  • Faulty accelerator pedal position (APP) sensor or throttle position sensor
  • Damaged wiring, corroded connectors or poor grounds in brake/APP circuits
  • Intermittent or failed CAN/serial communication between modules
  • Control module software fault or internal module failure
  • Incorrect sensor adjustment or mechanical binding in pedal assemblies

Symptoms

  • MIL/ABS/TC warning lamp illuminated
  • Cruise control disabled or faults stored
  • Engine reduced power/limp mode or unexpected torque limiting
  • Brake lights may be stuck ON or OFF
  • Inconsistent idle or sudden loss of engine response when braking/accelerating

What to check

  • Read freeze frame and stored data for P1555 and related codes
  • Inspect brake switch and accelerator pedal area for physical damage, binding or misadjustment
  • Scan live data: brake switch state, brake pedal position (if available), APP1/APP2 voltages and throttle actuator status
  • Check wiring harnesses and connector pins for corrosion, bent pins, water ingress or poor pin fit
  • Check for CAN bus communication errors and voltage supply to involved modules
  • Perform basic power/ground tests at sensors (battery voltage present, good ground)

Signal parameters

  • Brake switch: defined as ON/OFF; expected state = ON when pedal depressed, OFF when released (may be 0/5V or 0/12V depending on vehicle)
  • Accelerator pedal sensors (APP1/APP2): smooth, proportional voltages typically within ~0.5–4.5 V (manufacturer specific) and both channels must correlate
  • When brake is applied, APP voltage should be near idle (no significant acceleration request)
  • Typical implausibility rule: simultaneous high APP signal (wide open or above cruise threshold) and brake switch ON is invalid

Diagnostic algorithm

  1. Retrieve full DTC list and freeze frame, note engine speed, vehicle speed and pedal states at fault
  2. Clear codes and attempt to reproduce with a road or pedal test while monitoring live data
  3. Verify brake switch operation: physically actuate pedal while watching switch state; measure switch voltage/continuity with multimeter
  4. Verify APP sensors: compare APP1 and APP2 voltages while slowly depressing pedal — look for smooth, linear change and correlation between channels
  5. Inspect connectors and wiring continuity for brake switch and APP to the control modules; repair any damaged wiring or corrosion
  6. Check supply and ground at each sensor; confirm voltage reference (5V or 12V) is stable
  7. If CAN/communication faults present, check bus integrity, termination and module responses; repair or replace modules as needed
  8. If a specific sensor fails tests, replace the faulty component, clear codes and perform any required relearn/calibration procedures
  9. After repairs, confirm no reoccurrence of the code and perform a road test to verify normal operation

Likely causes

  • Brake switch stuck or mechanically misadjusted
  • APP sensor out of range or inconsistent dual sensor correlation
  • Damaged wiring or connector at brake switch or APP (short to power/ground)
  • Intermittent CAN bus errors between ABS/ECU and throttle modules

Fault status

⚠️ Status
Implausible brake-to-accelerator signal correlation detected — control module flagged inconsistent or out-of-range brake/accelerator inputs.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.5 hours

Similar codes

456

Browse 456 CHEVROLET manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

CHEVROLET

Your experience will help others
+100 karma for a short comment :)
Send to email
Code

P1555

CHRYSLER P — Powertrain

Electronic Variable Orifice Output

Brand: CHRYSLER
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty brake light switch or brake pedal position sensor
  • Faulty accelerator pedal position (APP) sensor or throttle position sensor
  • Damaged wiring, corroded connectors or poor grounds in brake/APP circuits
  • Intermittent or failed CAN/serial communication between modules
  • Control module software fault or internal module failure
  • Incorrect sensor adjustment or mechanical binding in pedal assemblies

Symptoms

  • MIL/ABS/TC warning lamp illuminated
  • Cruise control disabled or faults stored
  • Engine reduced power/limp mode or unexpected torque limiting
  • Brake lights may be stuck ON or OFF
  • Inconsistent idle or sudden loss of engine response when braking/accelerating

What to check

  • Read freeze frame and stored data for P1555 and related codes
  • Inspect brake switch and accelerator pedal area for physical damage, binding or misadjustment
  • Scan live data: brake switch state, brake pedal position (if available), APP1/APP2 voltages and throttle actuator status
  • Check wiring harnesses and connector pins for corrosion, bent pins, water ingress or poor pin fit
  • Check for CAN bus communication errors and voltage supply to involved modules
  • Perform basic power/ground tests at sensors (battery voltage present, good ground)

Signal parameters

  • Brake switch: defined as ON/OFF; expected state = ON when pedal depressed, OFF when released (may be 0/5V or 0/12V depending on vehicle)
  • Accelerator pedal sensors (APP1/APP2): smooth, proportional voltages typically within ~0.5–4.5 V (manufacturer specific) and both channels must correlate
  • When brake is applied, APP voltage should be near idle (no significant acceleration request)
  • Typical implausibility rule: simultaneous high APP signal (wide open or above cruise threshold) and brake switch ON is invalid

Diagnostic algorithm

  1. Retrieve full DTC list and freeze frame, note engine speed, vehicle speed and pedal states at fault
  2. Clear codes and attempt to reproduce with a road or pedal test while monitoring live data
  3. Verify brake switch operation: physically actuate pedal while watching switch state; measure switch voltage/continuity with multimeter
  4. Verify APP sensors: compare APP1 and APP2 voltages while slowly depressing pedal — look for smooth, linear change and correlation between channels
  5. Inspect connectors and wiring continuity for brake switch and APP to the control modules; repair any damaged wiring or corrosion
  6. Check supply and ground at each sensor; confirm voltage reference (5V or 12V) is stable
  7. If CAN/communication faults present, check bus integrity, termination and module responses; repair or replace modules as needed
  8. If a specific sensor fails tests, replace the faulty component, clear codes and perform any required relearn/calibration procedures
  9. After repairs, confirm no reoccurrence of the code and perform a road test to verify normal operation

Likely causes

  • Brake switch stuck or mechanically misadjusted
  • APP sensor out of range or inconsistent dual sensor correlation
  • Damaged wiring or connector at brake switch or APP (short to power/ground)
  • Intermittent CAN bus errors between ABS/ECU and throttle modules

Fault status

⚠️ Status
Implausible brake-to-accelerator signal correlation detected — control module flagged inconsistent or out-of-range brake/accelerator inputs.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.5 hours

Similar codes

Your experience will help others
+100 karma for a short comment :)
Send to email
Code

P1555

FIAT P — Powertrain

Brake/Accelerate signal implausible

Brand: FIAT
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty brake light switch or brake pedal position sensor
  • Faulty accelerator pedal position (APP) sensor or throttle position sensor
  • Damaged wiring, corroded connectors or poor grounds in brake/APP circuits
  • Intermittent or failed CAN/serial communication between modules
  • Control module software fault or internal module failure
  • Incorrect sensor adjustment or mechanical binding in pedal assemblies

Symptoms

  • MIL/ABS/TC warning lamp illuminated
  • Cruise control disabled or faults stored
  • Engine reduced power/limp mode or unexpected torque limiting
  • Brake lights may be stuck ON or OFF
  • Inconsistent idle or sudden loss of engine response when braking/accelerating

What to check

  • Read freeze frame and stored data for P1555 and related codes
  • Inspect brake switch and accelerator pedal area for physical damage, binding or misadjustment
  • Scan live data: brake switch state, brake pedal position (if available), APP1/APP2 voltages and throttle actuator status
  • Check wiring harnesses and connector pins for corrosion, bent pins, water ingress or poor pin fit
  • Check for CAN bus communication errors and voltage supply to involved modules
  • Perform basic power/ground tests at sensors (battery voltage present, good ground)

Signal parameters

  • Brake switch: defined as ON/OFF; expected state = ON when pedal depressed, OFF when released (may be 0/5V or 0/12V depending on vehicle)
  • Accelerator pedal sensors (APP1/APP2): smooth, proportional voltages typically within ~0.5–4.5 V (manufacturer specific) and both channels must correlate
  • When brake is applied, APP voltage should be near idle (no significant acceleration request)
  • Typical implausibility rule: simultaneous high APP signal (wide open or above cruise threshold) and brake switch ON is invalid

Diagnostic algorithm

  1. Retrieve full DTC list and freeze frame, note engine speed, vehicle speed and pedal states at fault
  2. Clear codes and attempt to reproduce with a road or pedal test while monitoring live data
  3. Verify brake switch operation: physically actuate pedal while watching switch state; measure switch voltage/continuity with multimeter
  4. Verify APP sensors: compare APP1 and APP2 voltages while slowly depressing pedal — look for smooth, linear change and correlation between channels
  5. Inspect connectors and wiring continuity for brake switch and APP to the control modules; repair any damaged wiring or corrosion
  6. Check supply and ground at each sensor; confirm voltage reference (5V or 12V) is stable
  7. If CAN/communication faults present, check bus integrity, termination and module responses; repair or replace modules as needed
  8. If a specific sensor fails tests, replace the faulty component, clear codes and perform any required relearn/calibration procedures
  9. After repairs, confirm no reoccurrence of the code and perform a road test to verify normal operation

Likely causes

  • Brake switch stuck or mechanically misadjusted
  • APP sensor out of range or inconsistent dual sensor correlation
  • Damaged wiring or connector at brake switch or APP (short to power/ground)
  • Intermittent CAN bus errors between ABS/ECU and throttle modules

Fault status

⚠️ Status
Implausible brake-to-accelerator signal correlation detected — control module flagged inconsistent or out-of-range brake/accelerator inputs.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.5 hours

Similar codes

Repair manuals

Manual library for FIAT

26

Browse 26 FIAT manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

Your experience will help others
+100 karma for a short comment :)
Send to email
Code

P1555

GM P — Powertrain

Electronic Variable Orifice Output

Brand: GM
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty brake light switch or brake pedal position sensor
  • Faulty accelerator pedal position (APP) sensor or throttle position sensor
  • Damaged wiring, corroded connectors or poor grounds in brake/APP circuits
  • Intermittent or failed CAN/serial communication between modules
  • Control module software fault or internal module failure
  • Incorrect sensor adjustment or mechanical binding in pedal assemblies

Symptoms

  • MIL/ABS/TC warning lamp illuminated
  • Cruise control disabled or faults stored
  • Engine reduced power/limp mode or unexpected torque limiting
  • Brake lights may be stuck ON or OFF
  • Inconsistent idle or sudden loss of engine response when braking/accelerating

What to check

  • Read freeze frame and stored data for P1555 and related codes
  • Inspect brake switch and accelerator pedal area for physical damage, binding or misadjustment
  • Scan live data: brake switch state, brake pedal position (if available), APP1/APP2 voltages and throttle actuator status
  • Check wiring harnesses and connector pins for corrosion, bent pins, water ingress or poor pin fit
  • Check for CAN bus communication errors and voltage supply to involved modules
  • Perform basic power/ground tests at sensors (battery voltage present, good ground)

Signal parameters

  • Brake switch: defined as ON/OFF; expected state = ON when pedal depressed, OFF when released (may be 0/5V or 0/12V depending on vehicle)
  • Accelerator pedal sensors (APP1/APP2): smooth, proportional voltages typically within ~0.5–4.5 V (manufacturer specific) and both channels must correlate
  • When brake is applied, APP voltage should be near idle (no significant acceleration request)
  • Typical implausibility rule: simultaneous high APP signal (wide open or above cruise threshold) and brake switch ON is invalid

Diagnostic algorithm

  1. Retrieve full DTC list and freeze frame, note engine speed, vehicle speed and pedal states at fault
  2. Clear codes and attempt to reproduce with a road or pedal test while monitoring live data
  3. Verify brake switch operation: physically actuate pedal while watching switch state; measure switch voltage/continuity with multimeter
  4. Verify APP sensors: compare APP1 and APP2 voltages while slowly depressing pedal — look for smooth, linear change and correlation between channels
  5. Inspect connectors and wiring continuity for brake switch and APP to the control modules; repair any damaged wiring or corrosion
  6. Check supply and ground at each sensor; confirm voltage reference (5V or 12V) is stable
  7. If CAN/communication faults present, check bus integrity, termination and module responses; repair or replace modules as needed
  8. If a specific sensor fails tests, replace the faulty component, clear codes and perform any required relearn/calibration procedures
  9. After repairs, confirm no reoccurrence of the code and perform a road test to verify normal operation

Likely causes

  • Brake switch stuck or mechanically misadjusted
  • APP sensor out of range or inconsistent dual sensor correlation
  • Damaged wiring or connector at brake switch or APP (short to power/ground)
  • Intermittent CAN bus errors between ABS/ECU and throttle modules

Fault status

⚠️ Status
Implausible brake-to-accelerator signal correlation detected — control module flagged inconsistent or out-of-range brake/accelerator inputs.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.5 hours

Similar codes

Your experience will help others
+100 karma for a short comment :)
Send to email
Code

P1555

GMC P — Powertrain

Electronic Variable Orifice Output

Brand: GMC
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty brake light switch or brake pedal position sensor
  • Faulty accelerator pedal position (APP) sensor or throttle position sensor
  • Damaged wiring, corroded connectors or poor grounds in brake/APP circuits
  • Intermittent or failed CAN/serial communication between modules
  • Control module software fault or internal module failure
  • Incorrect sensor adjustment or mechanical binding in pedal assemblies

Symptoms

  • MIL/ABS/TC warning lamp illuminated
  • Cruise control disabled or faults stored
  • Engine reduced power/limp mode or unexpected torque limiting
  • Brake lights may be stuck ON or OFF
  • Inconsistent idle or sudden loss of engine response when braking/accelerating

What to check

  • Read freeze frame and stored data for P1555 and related codes
  • Inspect brake switch and accelerator pedal area for physical damage, binding or misadjustment
  • Scan live data: brake switch state, brake pedal position (if available), APP1/APP2 voltages and throttle actuator status
  • Check wiring harnesses and connector pins for corrosion, bent pins, water ingress or poor pin fit
  • Check for CAN bus communication errors and voltage supply to involved modules
  • Perform basic power/ground tests at sensors (battery voltage present, good ground)

Signal parameters

  • Brake switch: defined as ON/OFF; expected state = ON when pedal depressed, OFF when released (may be 0/5V or 0/12V depending on vehicle)
  • Accelerator pedal sensors (APP1/APP2): smooth, proportional voltages typically within ~0.5–4.5 V (manufacturer specific) and both channels must correlate
  • When brake is applied, APP voltage should be near idle (no significant acceleration request)
  • Typical implausibility rule: simultaneous high APP signal (wide open or above cruise threshold) and brake switch ON is invalid

Diagnostic algorithm

  1. Retrieve full DTC list and freeze frame, note engine speed, vehicle speed and pedal states at fault
  2. Clear codes and attempt to reproduce with a road or pedal test while monitoring live data
  3. Verify brake switch operation: physically actuate pedal while watching switch state; measure switch voltage/continuity with multimeter
  4. Verify APP sensors: compare APP1 and APP2 voltages while slowly depressing pedal — look for smooth, linear change and correlation between channels
  5. Inspect connectors and wiring continuity for brake switch and APP to the control modules; repair any damaged wiring or corrosion
  6. Check supply and ground at each sensor; confirm voltage reference (5V or 12V) is stable
  7. If CAN/communication faults present, check bus integrity, termination and module responses; repair or replace modules as needed
  8. If a specific sensor fails tests, replace the faulty component, clear codes and perform any required relearn/calibration procedures
  9. After repairs, confirm no reoccurrence of the code and perform a road test to verify normal operation

Likely causes

  • Brake switch stuck or mechanically misadjusted
  • APP sensor out of range or inconsistent dual sensor correlation
  • Damaged wiring or connector at brake switch or APP (short to power/ground)
  • Intermittent CAN bus errors between ABS/ECU and throttle modules

Fault status

⚠️ Status
Implausible brake-to-accelerator signal correlation detected — control module flagged inconsistent or out-of-range brake/accelerator inputs.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.5 hours

Similar codes

Your experience will help others
+100 karma for a short comment :)
Send to email
Code

P1555

HUMMER P — Powertrain

Electronic Variable Orifice Output

Brand: HUMMER
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty brake light switch or brake pedal position sensor
  • Faulty accelerator pedal position (APP) sensor or throttle position sensor
  • Damaged wiring, corroded connectors or poor grounds in brake/APP circuits
  • Intermittent or failed CAN/serial communication between modules
  • Control module software fault or internal module failure
  • Incorrect sensor adjustment or mechanical binding in pedal assemblies

Symptoms

  • MIL/ABS/TC warning lamp illuminated
  • Cruise control disabled or faults stored
  • Engine reduced power/limp mode or unexpected torque limiting
  • Brake lights may be stuck ON or OFF
  • Inconsistent idle or sudden loss of engine response when braking/accelerating

What to check

  • Read freeze frame and stored data for P1555 and related codes
  • Inspect brake switch and accelerator pedal area for physical damage, binding or misadjustment
  • Scan live data: brake switch state, brake pedal position (if available), APP1/APP2 voltages and throttle actuator status
  • Check wiring harnesses and connector pins for corrosion, bent pins, water ingress or poor pin fit
  • Check for CAN bus communication errors and voltage supply to involved modules
  • Perform basic power/ground tests at sensors (battery voltage present, good ground)

Signal parameters

  • Brake switch: defined as ON/OFF; expected state = ON when pedal depressed, OFF when released (may be 0/5V or 0/12V depending on vehicle)
  • Accelerator pedal sensors (APP1/APP2): smooth, proportional voltages typically within ~0.5–4.5 V (manufacturer specific) and both channels must correlate
  • When brake is applied, APP voltage should be near idle (no significant acceleration request)
  • Typical implausibility rule: simultaneous high APP signal (wide open or above cruise threshold) and brake switch ON is invalid

Diagnostic algorithm

  1. Retrieve full DTC list and freeze frame, note engine speed, vehicle speed and pedal states at fault
  2. Clear codes and attempt to reproduce with a road or pedal test while monitoring live data
  3. Verify brake switch operation: physically actuate pedal while watching switch state; measure switch voltage/continuity with multimeter
  4. Verify APP sensors: compare APP1 and APP2 voltages while slowly depressing pedal — look for smooth, linear change and correlation between channels
  5. Inspect connectors and wiring continuity for brake switch and APP to the control modules; repair any damaged wiring or corrosion
  6. Check supply and ground at each sensor; confirm voltage reference (5V or 12V) is stable
  7. If CAN/communication faults present, check bus integrity, termination and module responses; repair or replace modules as needed
  8. If a specific sensor fails tests, replace the faulty component, clear codes and perform any required relearn/calibration procedures
  9. After repairs, confirm no reoccurrence of the code and perform a road test to verify normal operation

Likely causes

  • Brake switch stuck or mechanically misadjusted
  • APP sensor out of range or inconsistent dual sensor correlation
  • Damaged wiring or connector at brake switch or APP (short to power/ground)
  • Intermittent CAN bus errors between ABS/ECU and throttle modules

Fault status

⚠️ Status
Implausible brake-to-accelerator signal correlation detected — control module flagged inconsistent or out-of-range brake/accelerator inputs.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.5 hours

Similar codes

Repair manuals

Manual library for HUMMER

138

Browse 138 HUMMER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

HUMMER

Your experience will help others
+100 karma for a short comment :)
Send to email
Code

P1555

LAND ROVER P — Powertrain

Injector circuit range / performance - cylinder 5

AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty brake light switch or brake pedal position sensor
  • Faulty accelerator pedal position (APP) sensor or throttle position sensor
  • Damaged wiring, corroded connectors or poor grounds in brake/APP circuits
  • Intermittent or failed CAN/serial communication between modules
  • Control module software fault or internal module failure
  • Incorrect sensor adjustment or mechanical binding in pedal assemblies

Symptoms

  • MIL/ABS/TC warning lamp illuminated
  • Cruise control disabled or faults stored
  • Engine reduced power/limp mode or unexpected torque limiting
  • Brake lights may be stuck ON or OFF
  • Inconsistent idle or sudden loss of engine response when braking/accelerating

What to check

  • Read freeze frame and stored data for P1555 and related codes
  • Inspect brake switch and accelerator pedal area for physical damage, binding or misadjustment
  • Scan live data: brake switch state, brake pedal position (if available), APP1/APP2 voltages and throttle actuator status
  • Check wiring harnesses and connector pins for corrosion, bent pins, water ingress or poor pin fit
  • Check for CAN bus communication errors and voltage supply to involved modules
  • Perform basic power/ground tests at sensors (battery voltage present, good ground)

Signal parameters

  • Brake switch: defined as ON/OFF; expected state = ON when pedal depressed, OFF when released (may be 0/5V or 0/12V depending on vehicle)
  • Accelerator pedal sensors (APP1/APP2): smooth, proportional voltages typically within ~0.5–4.5 V (manufacturer specific) and both channels must correlate
  • When brake is applied, APP voltage should be near idle (no significant acceleration request)
  • Typical implausibility rule: simultaneous high APP signal (wide open or above cruise threshold) and brake switch ON is invalid

Diagnostic algorithm

  1. Retrieve full DTC list and freeze frame, note engine speed, vehicle speed and pedal states at fault
  2. Clear codes and attempt to reproduce with a road or pedal test while monitoring live data
  3. Verify brake switch operation: physically actuate pedal while watching switch state; measure switch voltage/continuity with multimeter
  4. Verify APP sensors: compare APP1 and APP2 voltages while slowly depressing pedal — look for smooth, linear change and correlation between channels
  5. Inspect connectors and wiring continuity for brake switch and APP to the control modules; repair any damaged wiring or corrosion
  6. Check supply and ground at each sensor; confirm voltage reference (5V or 12V) is stable
  7. If CAN/communication faults present, check bus integrity, termination and module responses; repair or replace modules as needed
  8. If a specific sensor fails tests, replace the faulty component, clear codes and perform any required relearn/calibration procedures
  9. After repairs, confirm no reoccurrence of the code and perform a road test to verify normal operation

Likely causes

  • Brake switch stuck or mechanically misadjusted
  • APP sensor out of range or inconsistent dual sensor correlation
  • Damaged wiring or connector at brake switch or APP (short to power/ground)
  • Intermittent CAN bus errors between ABS/ECU and throttle modules

Fault status

⚠️ Status
Implausible brake-to-accelerator signal correlation detected — control module flagged inconsistent or out-of-range brake/accelerator inputs.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.5 hours

Similar codes

320

Browse 320 LAND ROVER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

LAND ROVER

Your experience will help others
+100 karma for a short comment :)
Send to email
Code

P1555

OLDSMOBILE P — Powertrain

Electronic Variable Orifice Output

AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty brake light switch or brake pedal position sensor
  • Faulty accelerator pedal position (APP) sensor or throttle position sensor
  • Damaged wiring, corroded connectors or poor grounds in brake/APP circuits
  • Intermittent or failed CAN/serial communication between modules
  • Control module software fault or internal module failure
  • Incorrect sensor adjustment or mechanical binding in pedal assemblies

Symptoms

  • MIL/ABS/TC warning lamp illuminated
  • Cruise control disabled or faults stored
  • Engine reduced power/limp mode or unexpected torque limiting
  • Brake lights may be stuck ON or OFF
  • Inconsistent idle or sudden loss of engine response when braking/accelerating

What to check

  • Read freeze frame and stored data for P1555 and related codes
  • Inspect brake switch and accelerator pedal area for physical damage, binding or misadjustment
  • Scan live data: brake switch state, brake pedal position (if available), APP1/APP2 voltages and throttle actuator status
  • Check wiring harnesses and connector pins for corrosion, bent pins, water ingress or poor pin fit
  • Check for CAN bus communication errors and voltage supply to involved modules
  • Perform basic power/ground tests at sensors (battery voltage present, good ground)

Signal parameters

  • Brake switch: defined as ON/OFF; expected state = ON when pedal depressed, OFF when released (may be 0/5V or 0/12V depending on vehicle)
  • Accelerator pedal sensors (APP1/APP2): smooth, proportional voltages typically within ~0.5–4.5 V (manufacturer specific) and both channels must correlate
  • When brake is applied, APP voltage should be near idle (no significant acceleration request)
  • Typical implausibility rule: simultaneous high APP signal (wide open or above cruise threshold) and brake switch ON is invalid

Diagnostic algorithm

  1. Retrieve full DTC list and freeze frame, note engine speed, vehicle speed and pedal states at fault
  2. Clear codes and attempt to reproduce with a road or pedal test while monitoring live data
  3. Verify brake switch operation: physically actuate pedal while watching switch state; measure switch voltage/continuity with multimeter
  4. Verify APP sensors: compare APP1 and APP2 voltages while slowly depressing pedal — look for smooth, linear change and correlation between channels
  5. Inspect connectors and wiring continuity for brake switch and APP to the control modules; repair any damaged wiring or corrosion
  6. Check supply and ground at each sensor; confirm voltage reference (5V or 12V) is stable
  7. If CAN/communication faults present, check bus integrity, termination and module responses; repair or replace modules as needed
  8. If a specific sensor fails tests, replace the faulty component, clear codes and perform any required relearn/calibration procedures
  9. After repairs, confirm no reoccurrence of the code and perform a road test to verify normal operation

Likely causes

  • Brake switch stuck or mechanically misadjusted
  • APP sensor out of range or inconsistent dual sensor correlation
  • Damaged wiring or connector at brake switch or APP (short to power/ground)
  • Intermittent CAN bus errors between ABS/ECU and throttle modules

Fault status

⚠️ Status
Implausible brake-to-accelerator signal correlation detected — control module flagged inconsistent or out-of-range brake/accelerator inputs.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.5 hours

Similar codes

Your experience will help others
+100 karma for a short comment :)
Send to email
Code

P1555

SATURN P — Powertrain

Electronic Variable Orifice Output

Brand: SATURN
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty brake light switch or brake pedal position sensor
  • Faulty accelerator pedal position (APP) sensor or throttle position sensor
  • Damaged wiring, corroded connectors or poor grounds in brake/APP circuits
  • Intermittent or failed CAN/serial communication between modules
  • Control module software fault or internal module failure
  • Incorrect sensor adjustment or mechanical binding in pedal assemblies

Symptoms

  • MIL/ABS/TC warning lamp illuminated
  • Cruise control disabled or faults stored
  • Engine reduced power/limp mode or unexpected torque limiting
  • Brake lights may be stuck ON or OFF
  • Inconsistent idle or sudden loss of engine response when braking/accelerating

What to check

  • Read freeze frame and stored data for P1555 and related codes
  • Inspect brake switch and accelerator pedal area for physical damage, binding or misadjustment
  • Scan live data: brake switch state, brake pedal position (if available), APP1/APP2 voltages and throttle actuator status
  • Check wiring harnesses and connector pins for corrosion, bent pins, water ingress or poor pin fit
  • Check for CAN bus communication errors and voltage supply to involved modules
  • Perform basic power/ground tests at sensors (battery voltage present, good ground)

Signal parameters

  • Brake switch: defined as ON/OFF; expected state = ON when pedal depressed, OFF when released (may be 0/5V or 0/12V depending on vehicle)
  • Accelerator pedal sensors (APP1/APP2): smooth, proportional voltages typically within ~0.5–4.5 V (manufacturer specific) and both channels must correlate
  • When brake is applied, APP voltage should be near idle (no significant acceleration request)
  • Typical implausibility rule: simultaneous high APP signal (wide open or above cruise threshold) and brake switch ON is invalid

Diagnostic algorithm

  1. Retrieve full DTC list and freeze frame, note engine speed, vehicle speed and pedal states at fault
  2. Clear codes and attempt to reproduce with a road or pedal test while monitoring live data
  3. Verify brake switch operation: physically actuate pedal while watching switch state; measure switch voltage/continuity with multimeter
  4. Verify APP sensors: compare APP1 and APP2 voltages while slowly depressing pedal — look for smooth, linear change and correlation between channels
  5. Inspect connectors and wiring continuity for brake switch and APP to the control modules; repair any damaged wiring or corrosion
  6. Check supply and ground at each sensor; confirm voltage reference (5V or 12V) is stable
  7. If CAN/communication faults present, check bus integrity, termination and module responses; repair or replace modules as needed
  8. If a specific sensor fails tests, replace the faulty component, clear codes and perform any required relearn/calibration procedures
  9. After repairs, confirm no reoccurrence of the code and perform a road test to verify normal operation

Likely causes

  • Brake switch stuck or mechanically misadjusted
  • APP sensor out of range or inconsistent dual sensor correlation
  • Damaged wiring or connector at brake switch or APP (short to power/ground)
  • Intermittent CAN bus errors between ABS/ECU and throttle modules

Fault status

⚠️ Status
Implausible brake-to-accelerator signal correlation detected — control module flagged inconsistent or out-of-range brake/accelerator inputs.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.5 hours

Similar codes

Your experience will help others
+100 karma for a short comment :)
Send to email
Code

P1555

VOLKSWAGEN P — Powertrain

Charge Pressure Upper Limit Exceeded

AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Faulty brake light switch or brake pedal position sensor
  • Faulty accelerator pedal position (APP) sensor or throttle position sensor
  • Damaged wiring, corroded connectors or poor grounds in brake/APP circuits
  • Intermittent or failed CAN/serial communication between modules
  • Control module software fault or internal module failure
  • Incorrect sensor adjustment or mechanical binding in pedal assemblies

Symptoms

  • MIL/ABS/TC warning lamp illuminated
  • Cruise control disabled or faults stored
  • Engine reduced power/limp mode or unexpected torque limiting
  • Brake lights may be stuck ON or OFF
  • Inconsistent idle or sudden loss of engine response when braking/accelerating

What to check

  • Read freeze frame and stored data for P1555 and related codes
  • Inspect brake switch and accelerator pedal area for physical damage, binding or misadjustment
  • Scan live data: brake switch state, brake pedal position (if available), APP1/APP2 voltages and throttle actuator status
  • Check wiring harnesses and connector pins for corrosion, bent pins, water ingress or poor pin fit
  • Check for CAN bus communication errors and voltage supply to involved modules
  • Perform basic power/ground tests at sensors (battery voltage present, good ground)

Signal parameters

  • Brake switch: defined as ON/OFF; expected state = ON when pedal depressed, OFF when released (may be 0/5V or 0/12V depending on vehicle)
  • Accelerator pedal sensors (APP1/APP2): smooth, proportional voltages typically within ~0.5–4.5 V (manufacturer specific) and both channels must correlate
  • When brake is applied, APP voltage should be near idle (no significant acceleration request)
  • Typical implausibility rule: simultaneous high APP signal (wide open or above cruise threshold) and brake switch ON is invalid

Diagnostic algorithm

  1. Retrieve full DTC list and freeze frame, note engine speed, vehicle speed and pedal states at fault
  2. Clear codes and attempt to reproduce with a road or pedal test while monitoring live data
  3. Verify brake switch operation: physically actuate pedal while watching switch state; measure switch voltage/continuity with multimeter
  4. Verify APP sensors: compare APP1 and APP2 voltages while slowly depressing pedal — look for smooth, linear change and correlation between channels
  5. Inspect connectors and wiring continuity for brake switch and APP to the control modules; repair any damaged wiring or corrosion
  6. Check supply and ground at each sensor; confirm voltage reference (5V or 12V) is stable
  7. If CAN/communication faults present, check bus integrity, termination and module responses; repair or replace modules as needed
  8. If a specific sensor fails tests, replace the faulty component, clear codes and perform any required relearn/calibration procedures
  9. After repairs, confirm no reoccurrence of the code and perform a road test to verify normal operation

Likely causes

  • Brake switch stuck or mechanically misadjusted
  • APP sensor out of range or inconsistent dual sensor correlation
  • Damaged wiring or connector at brake switch or APP (short to power/ground)
  • Intermittent CAN bus errors between ABS/ECU and throttle modules

Fault status

⚠️ Status
Implausible brake-to-accelerator signal correlation detected — control module flagged inconsistent or out-of-range brake/accelerator inputs.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.5 hours

Similar codes

626

Browse 626 VOLKSWAGEN manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

VOLKSWAGEN

Your experience will help others
+100 karma for a short comment :)
Send to email