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P1125 – What Does It Mean and How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.


P1125 is an OBD-II Code that refers to Accelerator/Throttle Pedal Position Sensor Fault (GM Vehicles and related makes)


A P1125 code is a manufacturer specific diagnostic trouble code that occurs when the PCM/ECM detects that the throttle or pedal position sensor switch E has a low input. The pedal position sensor is a pressure-sensitive device located on the gas pedal. that the ECU when the gas pedal is depressed and how far it is depressed. 

When the ECU detects a low input from the pedal, the Check Engine Light illuminates and the P1125 code is stored in the ECU.


Common causes for this code include:

  • Bad Accelerator Pedal Position Sensor
  • Accelerator/Throttle Pedal Position Sensor circuit poor electrical connection
  • Accelerator/Throttle Pedal Position Sensor harness is open or shorted


The symptoms of a P1125 code are:

  • Illuminated Check Engine Light


To diagnose a P1125 DTC code, a technician would:

  1. Scan for codes in the ECM and look at the freeze frame data for failure.
  2. Visually inspect the accelerator pedal position sensor and the related wiring for damage or shorts.
  3. Check the electrical connector at the sensor for corrosion, poor contact, or damage.
  4. Measure the input voltage at the sensor to make sure it is within specifications.
  5. Test drive the vehicle to see if the condition still exists.

Common mistakes

The following are some of the most common mistakes that a technician may make when diagnosing a P1125 code:

  • Not thoroughly inspecting all the wiring and connectors for damage.
  • Not checking the input voltage at the sensor.
  • Not verifying that the condition still exists after test driving the vehicle.

How serious is this?

A P1125 code is a low-level fault and is not considered a serious issue. However, it should be diagnosed and repaired as soon as possible to prevent any further damage.

What repairs can fix the code?

The following are solutions that may fix this problem:

  • Repair or replace any wiring that is damaged
  • Check the input voltage at the sensor and make sure it is within specifications
  • Replace the accelerator pedal position sensor
  • Clean or replace the electrical connector at the sensor

Related codes

A P1125 is related to and may be accompanied by the following codes:

P0100 – Mass Air Flow Sensor Malfunction

P0106 – MAP/Barometric Pressure Sensor Malfunction

P0110 – Intake Air Temperature Sensor Malfunction

P0115 – Engine Coolant Temperature Sensor Malfunction

P0120 – Throttle Position Sensor Malfunction

P0220 – Fuel Pump Relay Circuit Malfunction


In conclusion, the P1125 code is a diagnostic trouble code that refers to a problem with the accelerator or throttle pedal position sensor. It is not a serious issue, but should be diagnosed and repaired as soon as possible to prevent further damage. Some common causes of this code include a bad accelerator pedal position sensor, a poor electrical connection, or a short in the wiring. The symptoms of this code are an illuminated Check Engine Light.