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DTC codes / GM codes / P1273

P1273 · GMAccelerator Pedal Position Sensor 1

P1273 on GM vehicles indicates that the engine control module (ECM) has detected an out-of-range or implausible signal from Accelerator Pedal Position (APP) Sensor 1, which is part of the electronic throttle control system. The ECM compares APP sensor 1 voltage against expected values and often cross-checks it with APP sensor 2; when the signal falls outside the calibrated range or disagrees with the second sensor, the ECM stores this code and typically limits engine power to a reduced level.

SystemPowertrain
Code typeGM specific
SeverityMedium
Fix difficultyIntermediate
AreaFuel and air metering (injector circuits)

Symptoms you may notice

  • Reduced engine power or limp mode, often with a message on the driver information center
  • The accelerator pedal feels unresponsive or requires more travel to accelerate
  • Hesitation or stumble when pressing the pedal from a stop
  • The engine may idle at a higher or erratic speed
  • Cruise control may be disabled or fail to engage
  • Often no symptoms besides the warning light if the fault is intermittent

Common causes, most likely first

  1. Worn or dirty accelerator pedal position sensor 1 inside the pedal assembly
  2. Damaged or chafed wiring between the APP sensor and the ECM, especially at the pedal connector
  3. Corroded or loose electrical connector at the accelerator pedal assembly
  4. Failed APP sensor 2 causing a correlation error that sets P1273
  5. Water intrusion into the pedal assembly or connector causing signal interference
  6. ECM software calibration issue or internal ECM fault (less common)
  7. Aftermarket floor mats or debris obstructing full pedal travel, causing implausible readings

How to diagnose and fix it

  1. Inspect the accelerator pedal area for aftermarket floor mats or debris that limit pedal travel, and remove any obstruction.
  2. Check for technical service bulletins (TSBs) or calibration updates for the vehicle's ECM related to APP sensor codes.
  3. Visually inspect the APP sensor connector and wiring for corrosion, chafing, or loose pins; repair as needed.
  4. Use a scan tool to view live data for APP sensor 1 and sensor 2 voltages through the full pedal sweep, looking for dead spots or non-linear response.
  5. Perform a voltage drop test on the sensor ground and reference circuits to rule out high resistance.
  6. If live data confirms an erratic or out-of-range signal from sensor 1, replace the accelerator pedal assembly (which includes both sensors on most GM models).
  7. After repair, clear codes and perform a throttle relearn or idle relearn procedure if required by the vehicle.

What most technicians miss on P1273

  • A dirty or sticking throttle body can cause APP sensor correlation codes because the ECM expects the throttle to respond to pedal input, so clean the throttle body before condemning the pedal.
  • Intermittent P1273 codes often stem from a poor connection at the pedal connector rather than a failed sensor, so wiggle-test the harness while watching live data.
  • Some GM vehicles require a battery disconnect or scan tool command to relearn the APP sensor after replacement, and skipping this step can leave the code stored.
  • Aftermarket floor mats that curl up under the pedal are a surprisingly common cause of implausible APP readings, especially on trucks and SUVs.
  • P1273 can be set by a failing APP sensor 2 even though the code names sensor 1, because the ECM cross-checks both sensors and flags the primary when correlation fails.

Can I keep driving with P1273?

You can usually drive the vehicle to a repair shop, but expect reduced engine power and avoid heavy acceleration or highway merging until the fault is fixed. If the pedal becomes completely unresponsive or the engine idles erratically, stop driving and have the vehicle towed.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for GM vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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