Code
P0123
Generic
P — Powertrain
Throttle/Pedal Position Sensor/Switch A Circuit High
Views:
UK: 30
EN: 57
RU: 31
AI status
Completed
Completed
100%
Causes
- Open, short, or damaged wiring in TPS A signal, reference, or ground circuit
- Corroded, loose, or contaminated TPS connector or pins
- Failed or contaminated throttle position sensor (potentiometer) or accelerator pedal position sensor
- Short to battery voltage (constant 12V) on the TPS signal wire
- Poor ground at sensor or ECM
- Faulty ECM input or internal circuit failure
Symptoms
- Check Engine Light (MIL) illuminated
- Reduced engine power or limp-home mode
- Erratic or poor throttle response, hesitation, or surging
- High or unstable idle in some cases
- Possible hesitation or stalling during throttle changes
What to check
- Read freeze frame and stored data with a scan tool; note related codes.
- Visually inspect TPS/accelerator pedal connector and wiring for damage, corrosion, pin push-out, or recent repair work.
- Backprobe TPS connector and measure reference voltage (typically ~5V) with key ON, engine OFF.
- Measure TPS signal voltage at closed throttle (key ON, engine OFF) and while moving throttle/pedal.
- Check sensor ground continuity to chassis/ECM ground.
- Wiggle test harness while monitoring voltage for intermittent changes.
Signal parameters
- Reference voltage (Vref): typically about 5.0 V (±0.5 V) from ECM
- Signal voltage at closed throttle/pedal: typically ~0.2–1.0 V (varies by vehicle); should be low
- Signal voltage at wide-open throttle: typically ~4.0–4.8 V
- Signal must change smoothly and monotonically with throttle/pedal movement (no jumps or drops)
- Type: analog voltage (potentiometer) or sensor linear output — expected rising voltage with opening throttle
Diagnostic algorithm
- Confirm code and check for related DTCs (P0122, P0121, P0221, P2138, etc.). Record freeze frame data.
- Perform a visual inspection of the TPS/pedal sensor connector and wiring harness for corrosion, damage, pin push-out, or evidence of shorting.
- With a DVOM, backprobe the connector: verify Vref (~5V), signal voltage at rest, and ground continuity to chassis/ECM ground. If Vref is missing or out of range, suspect ECM or wiring to Vref.
- Check signal voltage while slowly operating the throttle or pedal. Voltage should increase smoothly from closed to open. If the voltage is high at closed or erratic, suspect short to battery or bad sensor.
- If signal reads near battery voltage, disconnect the sensor and recheck the circuit. If the voltage remains high with sensor disconnected, inspect wiring for short to 12V or check for aftermarket taps.
- Perform continuity and resistance tests between the sensor pins and ECM pins to check for opens or shorts. Repair any wiring faults found.
- If wiring and grounds are good but the sensor output is still high or not linear, replace the TPS/pedal position sensor and retest.
- If problem persists after sensor replacement, test/replace ECM or consult manufacturer-specific diagnostic procedures for internal ECM faults.
- Clear codes and road test; verify the code does not return and signal values remain within expected ranges.
Likely causes
- Corroded/loose connector or pin(s) causing intermittent high voltage reading
- Short to 12V on the TPS signal circuit (pin contact or chafed harness)
- Failed TPS (internal short or worn potentiometer producing high voltage)
- Faulty reference (5V) supply or poor sensor ground
Fault status
Status
P0123 — Throttle/Pedal Position Sensor/Switch A Circuit High: ECM detects higher-than-expected voltage on the TPS A signal circuit.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Workshop Manuals
Available brands with manuals
2
AUDI 11
6-speed manual gearbox 0B1, front-wheel drive — Workshop Manual (Edition 05.2014)
Workshop ManualAudi A3 (1997) – 1.6L 4-cylinder (2‑valve) Engine Mechanical Components Service Manual (AEH, AKL, APF) – Edition 07.2002
Workshop ManualAUDI A3 (2004) Workshop Manual — 2.0L FSI Turbo (4‑cyl, 4‑valve) Engine, Mechanics — Edition 03.2017
Workshop ManualAudi A3 2004 — Electrical System (Workshop Manual, Edition 02.2018)
Workshop ManualAudi A4 / A4 Cabriolet – 4.2 l V8 (5‑valve, timing chains) – Workshop Manual (Mechanics) – Edition 04.2007
Workshop ManualAudi A4 / A4 Cabriolet — Auxiliary Heater Workshop Manual (Edition 08.2004)
Workshop ManualAudi A4 / A4 Cabriolet (1.8T 4‑cyl turbo) — Motronic Injection & Ignition System Service Manual (Edition 01.2015)
Workshop ManualAudi A8 (2003) — Electrical System Workshop Manual (Edition 08.2014)
Workshop ManualAudi Q4 e-tron (Type F4) - Self-study Programme SSP 685
Workshop ManualAudi Q8 (2018) — Electrical System Workshop Manual (Edition 05.2019)
Workshop ManualAudi Servicing Manual — 7‑Speed Dual Clutch Transmission 0CJ / 0CL / 0CK / 0DN / 0DP / 0HL (Edition 05.2018)
Workshop ManualLAND ROVER 3
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop ManualLand Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop ManualLand Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)
Workshop ManualYour experience will help others
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Code
P0123
GWM
P — Powertrain
- High Throttle Position Sensor / Switch A
Views:
UK: 4
EN: 19
RU: 9
AI status
Completed
Completed
100%
Causes
- Open, short, or damaged wiring in TPS A signal, reference, or ground circuit
- Corroded, loose, or contaminated TPS connector or pins
- Failed or contaminated throttle position sensor (potentiometer) or accelerator pedal position sensor
- Short to battery voltage (constant 12V) on the TPS signal wire
- Poor ground at sensor or ECM
- Faulty ECM input or internal circuit failure
Symptoms
- Check Engine Light (MIL) illuminated
- Reduced engine power or limp-home mode
- Erratic or poor throttle response, hesitation, or surging
- High or unstable idle in some cases
- Possible hesitation or stalling during throttle changes
What to check
- Read freeze frame and stored data with a scan tool; note related codes.
- Visually inspect TPS/accelerator pedal connector and wiring for damage, corrosion, pin push-out, or recent repair work.
- Backprobe TPS connector and measure reference voltage (typically ~5V) with key ON, engine OFF.
- Measure TPS signal voltage at closed throttle (key ON, engine OFF) and while moving throttle/pedal.
- Check sensor ground continuity to chassis/ECM ground.
- Wiggle test harness while monitoring voltage for intermittent changes.
Signal parameters
- Reference voltage (Vref): typically about 5.0 V (±0.5 V) from ECM
- Signal voltage at closed throttle/pedal: typically ~0.2–1.0 V (varies by vehicle); should be low
- Signal voltage at wide-open throttle: typically ~4.0–4.8 V
- Signal must change smoothly and monotonically with throttle/pedal movement (no jumps or drops)
- Type: analog voltage (potentiometer) or sensor linear output — expected rising voltage with opening throttle
Diagnostic algorithm
- Confirm code and check for related DTCs (P0122, P0121, P0221, P2138, etc.). Record freeze frame data.
- Perform a visual inspection of the TPS/pedal sensor connector and wiring harness for corrosion, damage, pin push-out, or evidence of shorting.
- With a DVOM, backprobe the connector: verify Vref (~5V), signal voltage at rest, and ground continuity to chassis/ECM ground. If Vref is missing or out of range, suspect ECM or wiring to Vref.
- Check signal voltage while slowly operating the throttle or pedal. Voltage should increase smoothly from closed to open. If the voltage is high at closed or erratic, suspect short to battery or bad sensor.
- If signal reads near battery voltage, disconnect the sensor and recheck the circuit. If the voltage remains high with sensor disconnected, inspect wiring for short to 12V or check for aftermarket taps.
- Perform continuity and resistance tests between the sensor pins and ECM pins to check for opens or shorts. Repair any wiring faults found.
- If wiring and grounds are good but the sensor output is still high or not linear, replace the TPS/pedal position sensor and retest.
- If problem persists after sensor replacement, test/replace ECM or consult manufacturer-specific diagnostic procedures for internal ECM faults.
- Clear codes and road test; verify the code does not return and signal values remain within expected ranges.
Likely causes
- Corroded/loose connector or pin(s) causing intermittent high voltage reading
- Short to 12V on the TPS signal circuit (pin contact or chafed harness)
- Failed TPS (internal short or worn potentiometer producing high voltage)
- Faulty reference (5V) supply or poor sensor ground
Fault status
Status
P0123 — Throttle/Pedal Position Sensor/Switch A Circuit High: ECM detects higher-than-expected voltage on the TPS A signal circuit.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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Code
P0123
HUMMER
P — Powertrain
Throttle Position (TP) Sensor Circuit High Voltage
Views:
UK: 12
EN: 29
RU: 15
AI status
Completed
Completed
100%
Causes
- Open, short, or damaged wiring in TPS A signal, reference, or ground circuit
- Corroded, loose, or contaminated TPS connector or pins
- Failed or contaminated throttle position sensor (potentiometer) or accelerator pedal position sensor
- Short to battery voltage (constant 12V) on the TPS signal wire
- Poor ground at sensor or ECM
- Faulty ECM input or internal circuit failure
Symptoms
- Check Engine Light (MIL) illuminated
- Reduced engine power or limp-home mode
- Erratic or poor throttle response, hesitation, or surging
- High or unstable idle in some cases
- Possible hesitation or stalling during throttle changes
What to check
- Read freeze frame and stored data with a scan tool; note related codes.
- Visually inspect TPS/accelerator pedal connector and wiring for damage, corrosion, pin push-out, or recent repair work.
- Backprobe TPS connector and measure reference voltage (typically ~5V) with key ON, engine OFF.
- Measure TPS signal voltage at closed throttle (key ON, engine OFF) and while moving throttle/pedal.
- Check sensor ground continuity to chassis/ECM ground.
- Wiggle test harness while monitoring voltage for intermittent changes.
Signal parameters
- Reference voltage (Vref): typically about 5.0 V (±0.5 V) from ECM
- Signal voltage at closed throttle/pedal: typically ~0.2–1.0 V (varies by vehicle); should be low
- Signal voltage at wide-open throttle: typically ~4.0–4.8 V
- Signal must change smoothly and monotonically with throttle/pedal movement (no jumps or drops)
- Type: analog voltage (potentiometer) or sensor linear output — expected rising voltage with opening throttle
Diagnostic algorithm
- Confirm code and check for related DTCs (P0122, P0121, P0221, P2138, etc.). Record freeze frame data.
- Perform a visual inspection of the TPS/pedal sensor connector and wiring harness for corrosion, damage, pin push-out, or evidence of shorting.
- With a DVOM, backprobe the connector: verify Vref (~5V), signal voltage at rest, and ground continuity to chassis/ECM ground. If Vref is missing or out of range, suspect ECM or wiring to Vref.
- Check signal voltage while slowly operating the throttle or pedal. Voltage should increase smoothly from closed to open. If the voltage is high at closed or erratic, suspect short to battery or bad sensor.
- If signal reads near battery voltage, disconnect the sensor and recheck the circuit. If the voltage remains high with sensor disconnected, inspect wiring for short to 12V or check for aftermarket taps.
- Perform continuity and resistance tests between the sensor pins and ECM pins to check for opens or shorts. Repair any wiring faults found.
- If wiring and grounds are good but the sensor output is still high or not linear, replace the TPS/pedal position sensor and retest.
- If problem persists after sensor replacement, test/replace ECM or consult manufacturer-specific diagnostic procedures for internal ECM faults.
- Clear codes and road test; verify the code does not return and signal values remain within expected ranges.
Likely causes
- Corroded/loose connector or pin(s) causing intermittent high voltage reading
- Short to 12V on the TPS signal circuit (pin contact or chafed harness)
- Failed TPS (internal short or worn potentiometer producing high voltage)
- Faulty reference (5V) supply or poor sensor ground
Fault status
Status
P0123 — Throttle/Pedal Position Sensor/Switch A Circuit High: ECM detects higher-than-expected voltage on the TPS A signal circuit.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
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0
Send to email
Code
P0123
ISUZU
P — Powertrain
Throttle Position Sensor Circuit High
Views:
UK: 22
EN: 48
RU: 20
AI status
Completed
Completed
100%
Causes
- Open, short, or damaged wiring in TPS A signal, reference, or ground circuit
- Corroded, loose, or contaminated TPS connector or pins
- Failed or contaminated throttle position sensor (potentiometer) or accelerator pedal position sensor
- Short to battery voltage (constant 12V) on the TPS signal wire
- Poor ground at sensor or ECM
- Faulty ECM input or internal circuit failure
Symptoms
- Check Engine Light (MIL) illuminated
- Reduced engine power or limp-home mode
- Erratic or poor throttle response, hesitation, or surging
- High or unstable idle in some cases
- Possible hesitation or stalling during throttle changes
What to check
- Read freeze frame and stored data with a scan tool; note related codes.
- Visually inspect TPS/accelerator pedal connector and wiring for damage, corrosion, pin push-out, or recent repair work.
- Backprobe TPS connector and measure reference voltage (typically ~5V) with key ON, engine OFF.
- Measure TPS signal voltage at closed throttle (key ON, engine OFF) and while moving throttle/pedal.
- Check sensor ground continuity to chassis/ECM ground.
- Wiggle test harness while monitoring voltage for intermittent changes.
Signal parameters
- Reference voltage (Vref): typically about 5.0 V (±0.5 V) from ECM
- Signal voltage at closed throttle/pedal: typically ~0.2–1.0 V (varies by vehicle); should be low
- Signal voltage at wide-open throttle: typically ~4.0–4.8 V
- Signal must change smoothly and monotonically with throttle/pedal movement (no jumps or drops)
- Type: analog voltage (potentiometer) or sensor linear output — expected rising voltage with opening throttle
Diagnostic algorithm
- Confirm code and check for related DTCs (P0122, P0121, P0221, P2138, etc.). Record freeze frame data.
- Perform a visual inspection of the TPS/pedal sensor connector and wiring harness for corrosion, damage, pin push-out, or evidence of shorting.
- With a DVOM, backprobe the connector: verify Vref (~5V), signal voltage at rest, and ground continuity to chassis/ECM ground. If Vref is missing or out of range, suspect ECM or wiring to Vref.
- Check signal voltage while slowly operating the throttle or pedal. Voltage should increase smoothly from closed to open. If the voltage is high at closed or erratic, suspect short to battery or bad sensor.
- If signal reads near battery voltage, disconnect the sensor and recheck the circuit. If the voltage remains high with sensor disconnected, inspect wiring for short to 12V or check for aftermarket taps.
- Perform continuity and resistance tests between the sensor pins and ECM pins to check for opens or shorts. Repair any wiring faults found.
- If wiring and grounds are good but the sensor output is still high or not linear, replace the TPS/pedal position sensor and retest.
- If problem persists after sensor replacement, test/replace ECM or consult manufacturer-specific diagnostic procedures for internal ECM faults.
- Clear codes and road test; verify the code does not return and signal values remain within expected ranges.
Likely causes
- Corroded/loose connector or pin(s) causing intermittent high voltage reading
- Short to 12V on the TPS signal circuit (pin contact or chafed harness)
- Failed TPS (internal short or worn potentiometer producing high voltage)
- Faulty reference (5V) supply or poor sensor ground
Fault status
Status
P0123 — Throttle/Pedal Position Sensor/Switch A Circuit High: ECM detects higher-than-expected voltage on the TPS A signal circuit.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email
Code
P0123
LAND ROVER
P — Powertrain
Throttle position sensor High input circuit
Views:
UK: 9
EN: 21
RU: 10
AI status
Completed
Completed
100%
Causes
- Open, short, or damaged wiring in TPS A signal, reference, or ground circuit
- Corroded, loose, or contaminated TPS connector or pins
- Failed or contaminated throttle position sensor (potentiometer) or accelerator pedal position sensor
- Short to battery voltage (constant 12V) on the TPS signal wire
- Poor ground at sensor or ECM
- Faulty ECM input or internal circuit failure
Symptoms
- Check Engine Light (MIL) illuminated
- Reduced engine power or limp-home mode
- Erratic or poor throttle response, hesitation, or surging
- High or unstable idle in some cases
- Possible hesitation or stalling during throttle changes
What to check
- Read freeze frame and stored data with a scan tool; note related codes.
- Visually inspect TPS/accelerator pedal connector and wiring for damage, corrosion, pin push-out, or recent repair work.
- Backprobe TPS connector and measure reference voltage (typically ~5V) with key ON, engine OFF.
- Measure TPS signal voltage at closed throttle (key ON, engine OFF) and while moving throttle/pedal.
- Check sensor ground continuity to chassis/ECM ground.
- Wiggle test harness while monitoring voltage for intermittent changes.
Signal parameters
- Reference voltage (Vref): typically about 5.0 V (±0.5 V) from ECM
- Signal voltage at closed throttle/pedal: typically ~0.2–1.0 V (varies by vehicle); should be low
- Signal voltage at wide-open throttle: typically ~4.0–4.8 V
- Signal must change smoothly and monotonically with throttle/pedal movement (no jumps or drops)
- Type: analog voltage (potentiometer) or sensor linear output — expected rising voltage with opening throttle
Diagnostic algorithm
- Confirm code and check for related DTCs (P0122, P0121, P0221, P2138, etc.). Record freeze frame data.
- Perform a visual inspection of the TPS/pedal sensor connector and wiring harness for corrosion, damage, pin push-out, or evidence of shorting.
- With a DVOM, backprobe the connector: verify Vref (~5V), signal voltage at rest, and ground continuity to chassis/ECM ground. If Vref is missing or out of range, suspect ECM or wiring to Vref.
- Check signal voltage while slowly operating the throttle or pedal. Voltage should increase smoothly from closed to open. If the voltage is high at closed or erratic, suspect short to battery or bad sensor.
- If signal reads near battery voltage, disconnect the sensor and recheck the circuit. If the voltage remains high with sensor disconnected, inspect wiring for short to 12V or check for aftermarket taps.
- Perform continuity and resistance tests between the sensor pins and ECM pins to check for opens or shorts. Repair any wiring faults found.
- If wiring and grounds are good but the sensor output is still high or not linear, replace the TPS/pedal position sensor and retest.
- If problem persists after sensor replacement, test/replace ECM or consult manufacturer-specific diagnostic procedures for internal ECM faults.
- Clear codes and road test; verify the code does not return and signal values remain within expected ranges.
Likely causes
- Corroded/loose connector or pin(s) causing intermittent high voltage reading
- Short to 12V on the TPS signal circuit (pin contact or chafed harness)
- Failed TPS (internal short or worn potentiometer producing high voltage)
- Faulty reference (5V) supply or poor sensor ground
Fault status
Status
P0123 — Throttle/Pedal Position Sensor/Switch A Circuit High: ECM detects higher-than-expected voltage on the TPS A signal circuit.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Workshop Manuals
Repair manuals for LAND ROVER
3
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop ManualLand Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop ManualLand Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)
Workshop ManualYour experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
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0
Send to email
Code
P0123
MITSUBISHI
P — Powertrain
TPS(main) high
Views:
UK: 12
EN: 30
RU: 12
AI status
Completed
Completed
100%
Causes
- Open, short, or damaged wiring in TPS A signal, reference, or ground circuit
- Corroded, loose, or contaminated TPS connector or pins
- Failed or contaminated throttle position sensor (potentiometer) or accelerator pedal position sensor
- Short to battery voltage (constant 12V) on the TPS signal wire
- Poor ground at sensor or ECM
- Faulty ECM input or internal circuit failure
Symptoms
- Check Engine Light (MIL) illuminated
- Reduced engine power or limp-home mode
- Erratic or poor throttle response, hesitation, or surging
- High or unstable idle in some cases
- Possible hesitation or stalling during throttle changes
What to check
- Read freeze frame and stored data with a scan tool; note related codes.
- Visually inspect TPS/accelerator pedal connector and wiring for damage, corrosion, pin push-out, or recent repair work.
- Backprobe TPS connector and measure reference voltage (typically ~5V) with key ON, engine OFF.
- Measure TPS signal voltage at closed throttle (key ON, engine OFF) and while moving throttle/pedal.
- Check sensor ground continuity to chassis/ECM ground.
- Wiggle test harness while monitoring voltage for intermittent changes.
Signal parameters
- Reference voltage (Vref): typically about 5.0 V (±0.5 V) from ECM
- Signal voltage at closed throttle/pedal: typically ~0.2–1.0 V (varies by vehicle); should be low
- Signal voltage at wide-open throttle: typically ~4.0–4.8 V
- Signal must change smoothly and monotonically with throttle/pedal movement (no jumps or drops)
- Type: analog voltage (potentiometer) or sensor linear output — expected rising voltage with opening throttle
Diagnostic algorithm
- Confirm code and check for related DTCs (P0122, P0121, P0221, P2138, etc.). Record freeze frame data.
- Perform a visual inspection of the TPS/pedal sensor connector and wiring harness for corrosion, damage, pin push-out, or evidence of shorting.
- With a DVOM, backprobe the connector: verify Vref (~5V), signal voltage at rest, and ground continuity to chassis/ECM ground. If Vref is missing or out of range, suspect ECM or wiring to Vref.
- Check signal voltage while slowly operating the throttle or pedal. Voltage should increase smoothly from closed to open. If the voltage is high at closed or erratic, suspect short to battery or bad sensor.
- If signal reads near battery voltage, disconnect the sensor and recheck the circuit. If the voltage remains high with sensor disconnected, inspect wiring for short to 12V or check for aftermarket taps.
- Perform continuity and resistance tests between the sensor pins and ECM pins to check for opens or shorts. Repair any wiring faults found.
- If wiring and grounds are good but the sensor output is still high or not linear, replace the TPS/pedal position sensor and retest.
- If problem persists after sensor replacement, test/replace ECM or consult manufacturer-specific diagnostic procedures for internal ECM faults.
- Clear codes and road test; verify the code does not return and signal values remain within expected ranges.
Likely causes
- Corroded/loose connector or pin(s) causing intermittent high voltage reading
- Short to 12V on the TPS signal circuit (pin contact or chafed harness)
- Failed TPS (internal short or worn potentiometer producing high voltage)
- Faulty reference (5V) supply or poor sensor ground
Fault status
Status
P0123 — Throttle/Pedal Position Sensor/Switch A Circuit High: ECM detects higher-than-expected voltage on the TPS A signal circuit.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email