P2138 - Throttle/Pedal Position Sensor/Switch 'D'/'E' Voltage Correlation

Repair Importance Level: 3/3
Repair Difficulty Level: 2/3   
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Possible causes

  • Accelerator Pedal Position Sensor harness is open or shorted
  • Accelerator Pedal Position Sensor circuit poor electrical connection
  • Faulty Accelerator Pedal Position Sensor
  • Faulty Electric Throttle Control Actuator

Possible symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)

P2138 Description

The Accelerator Pedal Position (APP) sensor is an input to the Powertrain Control Module (PCM) and used to determine the amount of torque requested by the operator. There are 2 pedal position signals in the sensor. Both signals, APP and APP2, have a positive slope (increasing angle, increasing voltage), but are offset and increase at different rates. The 2 pedal position signals make sure the PCM receives a correct input even if 1 signal has a concern. The PCM determines if a signal is incorrect by calculating where it should be, inferred from the other signals. If a concern is present with one of the circuits the other input is used. There are 2 reference voltage circuits, 2 signal return circuits, and 2 signal circuits (a total of 6 circuits and pins) between the PCM and the APP sensor assembly. The pedal position signal is converted to pedal travel degrees (rotary angle) by the PCM. The software converts these degrees to counts, which is the input to the torque based strategy. If the APP sensor inputs APP1 and APP2 disagree on the position of the accelerator pedal by more than an expected value, the P2138 is set.
OBDII Code P2138 - Throttle/Pedal Position Sensor/Switch 'D'/'E' Voltage Correlation - AutoCodes.com

P2138 Information for specific makes

  • P2138 ACURA Accelerator Pedal Position Sensor A/B Incorrect Voltage Correlation   
  • P2138 BUICK Accelerator Pedal Position Sensor 1-2 Correlation
  • P2138 CADILLAC Accelerator Pedal Position Sensor 1-2 Correlation
  • P2138 CHEVROLET Accelerator Pedal Position Sensor 1-2 Correlation   
  • P2138 DODGE Accelerator Pedal Position Sensor Circuit Range/Performance
  • P2138 FORD Throttle/Pedal Position Sensor/Switch 'D'/'E' Voltage Correlation
  • P2138 GMC Accelerator Pedal Position Sensor 1-2 Correlation
  • P2138 HONDA Accelerator Pedal Position Sensor A/B Incorrect Voltage Correlation   
  • P2138 HYUNDAI Accelerator Pedal Position Sensor Circuit Range/Performance
  • P2138 INFINITI Accelerator Pedal Position Sensor Circuit Range/Performance
  • P2138 LEXUS Throttle Pedal Position Sensor/Switch 'D'/'E' Voltage Correlation
  • P2138 LINCOLN Throttle/Pedal Position Sensor/Switch 'D'/'E' Voltage Correlation
  • P2138 MERCEDES-BENZ Throttle/Pedal Position Sensor/Switch 'D'/'E' Voltage Correlation
  • P2138 MERCURY Throttle/Pedal Position Sensor/Switch 'D'/'E' Voltage Correlation
  • P2138 NISSAN Accelerator Pedal Position Sensor Circuit Range/Performance
  • P2138 PONTIAC Accelerator Pedal Position Sensor 1-2 Correlation
  • P2138 SATURN Accelerator Pedal Position Sensor 1-2 Correlation
  • P2138 SCION Throttle Pedal Position Sensor/Switch 'D'/'E' Voltage Correlation
  • P2138 TOYOTA Throttle Pedal Position Sensor/Switch 'D'/'E' Voltage Correlation

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