P1282

Code

GMC P — Powertrain

Accelerator Pedal Position Sensor 2 Circuit Low Voltage

Brand: GMC

Type: P — Powertrain

Views: UK: 25 EN: 35 RU: 21

AI status

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Page language: EN

Causes

Damaged or disconnected wiring/connector to APP sensor 2
Corroded or loose connector pins
Short to ground on the sensor 2 signal wire
Failed APP sensor (internal short/open or degraded electronics)
Low battery or poor chassis/engine ground affecting reference voltage
Faulty PCM (rare) or incorrect replacement PCM programming

Symptoms

Illuminated MIL / Check Engine Light
Reduced engine power or limp-home mode
Poor or delayed throttle response, hesitation
Engine may start normally but throttle is unresponsive
Possible related DTCs for APP sensor 1, correlation, or throttle control

What to check

Read and record DTCs and freeze frame data with a scan tool
Check battery voltage (should be ~12.6 V at rest, >= 11.5 V with key ON)
Visually inspect pedal connector and harness for damage, corrosion, or loose pins
Backprobe APP sensor 2 signal, reference (5V) and ground with key ON (engine off)
Check for related codes (APP sensor 1, correlation codes) that help diagnosis
Wiggle harness while monitoring signal to check intermittent faults

Signal parameters

Reference voltage (VREF) from PCM: ~5.0 V (may vary by model; consult service manual)
Sensor 2 output at rest (closed throttle): typically ~0.2–0.8 V (model dependent)
Sensor 2 output at wide-open throttle: typically ~4.0–4.5 V (model dependent)
Signal wiring continuity to PCM: near 0 ohms (small harness length dependent)
Ground circuit resistance: low, typically
No short to ground or battery on the signal wire when key ON

Diagnostic algorithm

Connect a scan tool, record P1282 and any other related codes and freeze frame data.
Verify battery voltage is good. Poor battery/charging can cause erroneous low readings.
Visually inspect the accelerator pedal connector and wiring for corrosion, damage or pinch points. Repair any obvious faults.
With key ON (engine off), backprobe the pedal connector: verify VREF ~5 V, ground continuity, and the APP2 signal voltage. Note values at rest.
Slowly depress the pedal while watching the APP2 signal on the scan tool or multimeter. Confirm the voltage increases smoothly without drops or noise.
If APP2 signal is stuck low, check continuity between the sensor signal pin and the PCM signal terminal. Check for short to ground or to battery using an ohmmeter or power-off tests.
If wiring and connector are good but signal stays low or out of range, remove pedal (if required) and bench test sensor per manufacturer procedure or compare sensor 1 vs sensor 2 signals (they should track), or swap/replace pedal assembly if sensors are integrated.
After repairs, clear codes, perform a relearn/calibration if required by the manufacturer, and road-test while monitoring live data to confirm normal operation.
If all wiring and sensor evidence are good and the fault persists, consider PCM input pin testing or replacement as a last resort (verify with manufacturer guidance).

Likely causes

Corroded/loose connector or pin at the pedal assembly
Broken or shorted signal wiring between pedal and PCM
Failed APP sensor 2 inside the pedal assembly

Fault status

⚠️ Status

P1282 — Accelerator Pedal Position Sensor 2 Circuit Low Voltage. PCM detected the APP sensor 2 output below expected range. Possible causes include damaged wiring/connector, short to ground, failed pedal sensor, or low reference voltage.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours

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