Code
P0638
Generic
P — Powertrain
Throttle Actuator Control Range/Performance Bank 1
Views:
UK: 19
EN: 24
RU: 30
AI status
Completed
Completed
100%
Causes
- Faulty throttle body (actuator motor or position sensor)
- Contaminated or mechanically bound throttle plate
- Faulty accelerator pedal position (APP) sensor or sensor correlation fault
- Damaged wiring, chafed insulation, corroded or loose connectors to throttle body or APP
- Blown fuse, poor power or ground to throttle actuator motor/position sensor
- PCM or throttle control module fault (driver circuit failure)
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Reduced engine power or limp mode (limited throttle)
- Poor throttle response, hesitation or surging
- Irregular or high/low idle speed
- Stored and recurring throttle-related DTCs
- Possible failure to accelerate or inability to reach expected throttle openings
What to check
- Read and record all stored/active/pending DTCs and freeze frame data with a capable scan tool
- Check for related codes (APP sensors, TPS, power/ground circuits, communication faults)
- Monitor live data: commanded throttle angle vs actual throttle angle, APP sensor voltages/correlations, motor current and duty cycle
- Inspect throttle body and intake for carbon buildup or mechanical obstruction
- Visually inspect wiring and connectors at the throttle body and pedal assembly for corrosion, pin damage or water intrusion
- Check fuses and relays that feed the throttle actuator/PCM power and ground circuits
Signal parameters
- Accelerator pedal sensor voltages (sensor 1 & sensor 2): typically ~0.5 V at rest to ~4.5 V at full travel (exact values vary by vehicle)
- Throttle position / throttle plate angle: idle ~0–10°; wide open typically 60–90° depending on design
- Commanded throttle angle vs actual throttle angle: should closely follow commands (small degree difference)
- Throttle motor supply: battery voltage (~12 V) present at the motor supply pin when commanded
- Motor drive duty cycle or current (varies with command) — look for expected changes when commanding throttle
Diagnostic algorithm
- Retrieve and save all DTCs and freeze frame data. Note MIL status and any patterns. 2) Verify related codes (APP, TPS, power, communication) and address them first if present. 3) With a scan tool, monitor APP sensors (both channels if present) and compare their correlation to commanded throttle and actual throttle angle. Look for sensor mismatch or stuck readings. 4) Perform visual inspection: check throttle body for carbon, binding, or foreign objects; inspect harness and connectors for corrosion, broken wires, bent pins, and secure connections. 5) Check power and ground: verify fuses, relays, and battery voltage at the throttle body power pin(s); verify a good ground at the throttle body. 6) Perform wiggle test and backprobe connectors while monitoring live data to look for intermittent failures. 7) If mechanical contamination suspected, clean throttle body per service instructions, then perform throttle relearn/calibration. 8) If motor or position sensor suspected, measure throttle motor resistance and position sensor voltage sweep while commanding throttle with scan tool (compare to spec). Use oscilloscope where available to view motor driver signals. 9) If wiring and throttle body fail tests, replace throttle body or repair wiring as indicated. After repairs, clear codes and perform relearn/calibration and verify on road test. 10) If problem persists after replacement and wiring verified, consider PCM/throttle control module diagnosis or replacement as last resort (consult manufacturer procedures).
Likely causes
- Throttle body actuator motor or internal potentiometer/position sensor out of tolerance
- Carbon build-up causing throttle plate binding or slow response
- Wiring harness connector corrosion or broken wires at the throttle body/connector
- Faulty APP-to-PCM correlation (APP sensors not matching each other or stuck)
Fault status
Status
P0638 — Throttle actuator control range/performance fault on bank 1. PCM reports commanded throttle and actual throttle position are not within expected range or performance limits.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
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Code
P0638
HUMMER
P — Powertrain
Throttle Actuator Control (TAC) Command Performance
Views:
UK: 10
EN: 10
RU: 14
AI status
Completed
Completed
100%
Causes
- Faulty throttle body (actuator motor or position sensor)
- Contaminated or mechanically bound throttle plate
- Faulty accelerator pedal position (APP) sensor or sensor correlation fault
- Damaged wiring, chafed insulation, corroded or loose connectors to throttle body or APP
- Blown fuse, poor power or ground to throttle actuator motor/position sensor
- PCM or throttle control module fault (driver circuit failure)
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Reduced engine power or limp mode (limited throttle)
- Poor throttle response, hesitation or surging
- Irregular or high/low idle speed
- Stored and recurring throttle-related DTCs
- Possible failure to accelerate or inability to reach expected throttle openings
What to check
- Read and record all stored/active/pending DTCs and freeze frame data with a capable scan tool
- Check for related codes (APP sensors, TPS, power/ground circuits, communication faults)
- Monitor live data: commanded throttle angle vs actual throttle angle, APP sensor voltages/correlations, motor current and duty cycle
- Inspect throttle body and intake for carbon buildup or mechanical obstruction
- Visually inspect wiring and connectors at the throttle body and pedal assembly for corrosion, pin damage or water intrusion
- Check fuses and relays that feed the throttle actuator/PCM power and ground circuits
Signal parameters
- Accelerator pedal sensor voltages (sensor 1 & sensor 2): typically ~0.5 V at rest to ~4.5 V at full travel (exact values vary by vehicle)
- Throttle position / throttle plate angle: idle ~0–10°; wide open typically 60–90° depending on design
- Commanded throttle angle vs actual throttle angle: should closely follow commands (small degree difference)
- Throttle motor supply: battery voltage (~12 V) present at the motor supply pin when commanded
- Motor drive duty cycle or current (varies with command) — look for expected changes when commanding throttle
Diagnostic algorithm
- Retrieve and save all DTCs and freeze frame data. Note MIL status and any patterns. 2) Verify related codes (APP, TPS, power, communication) and address them first if present. 3) With a scan tool, monitor APP sensors (both channels if present) and compare their correlation to commanded throttle and actual throttle angle. Look for sensor mismatch or stuck readings. 4) Perform visual inspection: check throttle body for carbon, binding, or foreign objects; inspect harness and connectors for corrosion, broken wires, bent pins, and secure connections. 5) Check power and ground: verify fuses, relays, and battery voltage at the throttle body power pin(s); verify a good ground at the throttle body. 6) Perform wiggle test and backprobe connectors while monitoring live data to look for intermittent failures. 7) If mechanical contamination suspected, clean throttle body per service instructions, then perform throttle relearn/calibration. 8) If motor or position sensor suspected, measure throttle motor resistance and position sensor voltage sweep while commanding throttle with scan tool (compare to spec). Use oscilloscope where available to view motor driver signals. 9) If wiring and throttle body fail tests, replace throttle body or repair wiring as indicated. After repairs, clear codes and perform relearn/calibration and verify on road test. 10) If problem persists after replacement and wiring verified, consider PCM/throttle control module diagnosis or replacement as last resort (consult manufacturer procedures).
Likely causes
- Throttle body actuator motor or internal potentiometer/position sensor out of tolerance
- Carbon build-up causing throttle plate binding or slow response
- Wiring harness connector corrosion or broken wires at the throttle body/connector
- Faulty APP-to-PCM correlation (APP sensors not matching each other or stuck)
Fault status
Status
P0638 — Throttle actuator control range/performance fault on bank 1. PCM reports commanded throttle and actual throttle position are not within expected range or performance limits.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
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Code
P0638
ISUZU
P — Powertrain
Throttle Actuator Control Range/Performance
Views:
UK: 15
EN: 19
RU: 23
AI status
Completed
Completed
100%
Causes
- Faulty throttle body (actuator motor or position sensor)
- Contaminated or mechanically bound throttle plate
- Faulty accelerator pedal position (APP) sensor or sensor correlation fault
- Damaged wiring, chafed insulation, corroded or loose connectors to throttle body or APP
- Blown fuse, poor power or ground to throttle actuator motor/position sensor
- PCM or throttle control module fault (driver circuit failure)
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Reduced engine power or limp mode (limited throttle)
- Poor throttle response, hesitation or surging
- Irregular or high/low idle speed
- Stored and recurring throttle-related DTCs
- Possible failure to accelerate or inability to reach expected throttle openings
What to check
- Read and record all stored/active/pending DTCs and freeze frame data with a capable scan tool
- Check for related codes (APP sensors, TPS, power/ground circuits, communication faults)
- Monitor live data: commanded throttle angle vs actual throttle angle, APP sensor voltages/correlations, motor current and duty cycle
- Inspect throttle body and intake for carbon buildup or mechanical obstruction
- Visually inspect wiring and connectors at the throttle body and pedal assembly for corrosion, pin damage or water intrusion
- Check fuses and relays that feed the throttle actuator/PCM power and ground circuits
Signal parameters
- Accelerator pedal sensor voltages (sensor 1 & sensor 2): typically ~0.5 V at rest to ~4.5 V at full travel (exact values vary by vehicle)
- Throttle position / throttle plate angle: idle ~0–10°; wide open typically 60–90° depending on design
- Commanded throttle angle vs actual throttle angle: should closely follow commands (small degree difference)
- Throttle motor supply: battery voltage (~12 V) present at the motor supply pin when commanded
- Motor drive duty cycle or current (varies with command) — look for expected changes when commanding throttle
Diagnostic algorithm
- Retrieve and save all DTCs and freeze frame data. Note MIL status and any patterns. 2) Verify related codes (APP, TPS, power, communication) and address them first if present. 3) With a scan tool, monitor APP sensors (both channels if present) and compare their correlation to commanded throttle and actual throttle angle. Look for sensor mismatch or stuck readings. 4) Perform visual inspection: check throttle body for carbon, binding, or foreign objects; inspect harness and connectors for corrosion, broken wires, bent pins, and secure connections. 5) Check power and ground: verify fuses, relays, and battery voltage at the throttle body power pin(s); verify a good ground at the throttle body. 6) Perform wiggle test and backprobe connectors while monitoring live data to look for intermittent failures. 7) If mechanical contamination suspected, clean throttle body per service instructions, then perform throttle relearn/calibration. 8) If motor or position sensor suspected, measure throttle motor resistance and position sensor voltage sweep while commanding throttle with scan tool (compare to spec). Use oscilloscope where available to view motor driver signals. 9) If wiring and throttle body fail tests, replace throttle body or repair wiring as indicated. After repairs, clear codes and perform relearn/calibration and verify on road test. 10) If problem persists after replacement and wiring verified, consider PCM/throttle control module diagnosis or replacement as last resort (consult manufacturer procedures).
Likely causes
- Throttle body actuator motor or internal potentiometer/position sensor out of tolerance
- Carbon build-up causing throttle plate binding or slow response
- Wiring harness connector corrosion or broken wires at the throttle body/connector
- Faulty APP-to-PCM correlation (APP sensors not matching each other or stuck)
Fault status
Status
P0638 — Throttle actuator control range/performance fault on bank 1. PCM reports commanded throttle and actual throttle position are not within expected range or performance limits.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
Similar codes
Your experience will help others
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Was this AI description helpful?
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Code
P0638
MITSUBISHI
P — Powertrain
Throttle actuator control range
Views:
UK: 10
EN: 10
RU: 15
AI status
Completed
Completed
100%
Causes
- Faulty throttle body (actuator motor or position sensor)
- Contaminated or mechanically bound throttle plate
- Faulty accelerator pedal position (APP) sensor or sensor correlation fault
- Damaged wiring, chafed insulation, corroded or loose connectors to throttle body or APP
- Blown fuse, poor power or ground to throttle actuator motor/position sensor
- PCM or throttle control module fault (driver circuit failure)
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Reduced engine power or limp mode (limited throttle)
- Poor throttle response, hesitation or surging
- Irregular or high/low idle speed
- Stored and recurring throttle-related DTCs
- Possible failure to accelerate or inability to reach expected throttle openings
What to check
- Read and record all stored/active/pending DTCs and freeze frame data with a capable scan tool
- Check for related codes (APP sensors, TPS, power/ground circuits, communication faults)
- Monitor live data: commanded throttle angle vs actual throttle angle, APP sensor voltages/correlations, motor current and duty cycle
- Inspect throttle body and intake for carbon buildup or mechanical obstruction
- Visually inspect wiring and connectors at the throttle body and pedal assembly for corrosion, pin damage or water intrusion
- Check fuses and relays that feed the throttle actuator/PCM power and ground circuits
Signal parameters
- Accelerator pedal sensor voltages (sensor 1 & sensor 2): typically ~0.5 V at rest to ~4.5 V at full travel (exact values vary by vehicle)
- Throttle position / throttle plate angle: idle ~0–10°; wide open typically 60–90° depending on design
- Commanded throttle angle vs actual throttle angle: should closely follow commands (small degree difference)
- Throttle motor supply: battery voltage (~12 V) present at the motor supply pin when commanded
- Motor drive duty cycle or current (varies with command) — look for expected changes when commanding throttle
Diagnostic algorithm
- Retrieve and save all DTCs and freeze frame data. Note MIL status and any patterns. 2) Verify related codes (APP, TPS, power, communication) and address them first if present. 3) With a scan tool, monitor APP sensors (both channels if present) and compare their correlation to commanded throttle and actual throttle angle. Look for sensor mismatch or stuck readings. 4) Perform visual inspection: check throttle body for carbon, binding, or foreign objects; inspect harness and connectors for corrosion, broken wires, bent pins, and secure connections. 5) Check power and ground: verify fuses, relays, and battery voltage at the throttle body power pin(s); verify a good ground at the throttle body. 6) Perform wiggle test and backprobe connectors while monitoring live data to look for intermittent failures. 7) If mechanical contamination suspected, clean throttle body per service instructions, then perform throttle relearn/calibration. 8) If motor or position sensor suspected, measure throttle motor resistance and position sensor voltage sweep while commanding throttle with scan tool (compare to spec). Use oscilloscope where available to view motor driver signals. 9) If wiring and throttle body fail tests, replace throttle body or repair wiring as indicated. After repairs, clear codes and perform relearn/calibration and verify on road test. 10) If problem persists after replacement and wiring verified, consider PCM/throttle control module diagnosis or replacement as last resort (consult manufacturer procedures).
Likely causes
- Throttle body actuator motor or internal potentiometer/position sensor out of tolerance
- Carbon build-up causing throttle plate binding or slow response
- Wiring harness connector corrosion or broken wires at the throttle body/connector
- Faulty APP-to-PCM correlation (APP sensors not matching each other or stuck)
Fault status
Status
P0638 — Throttle actuator control range/performance fault on bank 1. PCM reports commanded throttle and actual throttle position are not within expected range or performance limits.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
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