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GTECH Calibration
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P1281

Accelerator Pedal Position (APP) Sensor 2 Performance.

  • Buick
  • Powertrain
  • Manufacturer code
  • Medium severity

How this code is built

P
SystemPowertrain
1
Defined byThe manufacturer
2
AreaFuel and air metering (injector circuit)
81
FaultThe specific fault in that area

What it means

On a Buick, P1281 means the engine control module has judged the signal from Accelerator Pedal Position (APP) sensor 2 to be implausible or not performing as expected. The module compares the pedal sensor signals with each other and with expected values, and sets the code when sensor 2 disagrees with the others or sits outside its expected range. The exact test and the number of sensor circuits vary by model and engine, so check the manufacturer data for the vehicle.

Symptoms

  • Malfunction indicator lamp or reduced engine power warning lit
  • Reduced engine power or limited throttle response
  • Poor or delayed acceleration
  • Engine stuck at a high or fixed idle speed
  • Hesitation or surging when pressing the pedal
  • Cruise control not working

Possible causes

  • Faulty accelerator pedal assembly with a worn or drifting APP sensor 2 tracklikely
  • Damaged wiring, chafed insulation or an open or short circuit in the APP sensor 2 signal, reference or ground wireslikely
  • Corroded, loose or contaminated connector terminals at the pedal or the control modulelikely
  • Poor sensor ground or a fault in the 5 volt reference supply shared with other sensorspossible
  • Water ingress or contamination inside the pedal sensor housingpossible
  • Fault within the engine control modulerare
  • Outdated control module calibration where the manufacturer has issued a fix for the modelrare

How to diagnose

  1. Read all stored and pending codes and the freeze frame data, noting any other pedal, throttle or 5 volt reference codes
  2. Check for relevant technical service bulletins and any calibration updates for the specific model and engine
  3. Inspect the pedal assembly, its connector and the wiring for damage, corrosion, moisture or chafing
  4. With a scan tool, watch APP sensors 1 and 2 while slowly pressing and releasing the pedal and look for dropouts, jumps or a mismatch between the two
  5. Check the sensor 2 reference voltage, signal and ground at the pedal connector against the manufacturer specification
  6. Test the wiring for continuity and for shorts to ground, voltage or other circuits between the pedal and the control module
  7. Check the engine control module power and earth supplies and the condition of its connectors
  8. Clear the code and road test to confirm whether it returns, before considering the control module

How to fix

  • Replace the accelerator pedal assembly if the sensor readings are erratic or out of specification
  • Repair or replace damaged wiring and clean or renew corroded connector terminals
  • Restore a faulty sensor ground or 5 volt reference circuit, including any shared fault on other sensors
  • Dry out and seal against water ingress, then replace the pedal if the sensor is contaminated
  • Update the control module calibration only if the manufacturer lists an outdated calibration as the cause
  • Replace or reprogram the engine control module only after all wiring and sensor faults have been ruled out

Can I keep driving?

Medium severity

The car may go into reduced power mode and respond unpredictably to the pedal, which can be unsafe in traffic. Avoid driving it further than necessary and have it repaired soon.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.

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