Code
P1280
CHRYSLER
P — Powertrain
Accelerator Pedal Position (APP) Sensor 2 Circuit
Views:
UK: 18
EN: 22
RU: 20
AI status
Completed
Completed
100%
Causes
- Open or short in APP sensor 2 wiring (to PCM)
- Poor or corroded connector at APP pedal or PCM
- Failed APP sensor (pedal assembly)
- Short to 5V reference or ground
- Intermittent wiring contact from chafing or pinched harness
- PCM fault (rare)
Symptoms
- Check Engine Light (MIL) illuminated
- Reduced engine power / limp-home mode
- Poor or delayed throttle response
- Engine may idle normally but not accept full throttle
- Possible stored or active multiple APP/throttle-related DTCs
What to check
- Read/record DTCs and freeze-frame data with a scan tool
- Check live data: APP Sensor 1 and Sensor 2 voltages/percentages while key ON/engine off and while pressing pedal
- Visually inspect APP pedal connector and wiring harness for damage, corrosion or water
- Wiggle harness/connectors while watching live data for intermittent changes
- Measure VREF (usually +5V) and sensor ground at pedal connector
- Perform continuity and resistance checks between sensor pins and PCM pins (with battery disconnected)
Signal parameters
- Reference voltage (VREF): ~5.0 V (key ON)
- Sensor 2 output: typically ~0.5–4.5 V across pedal travel (rest ≈0.5–1.5 V; full travel ≈3.5–4.5 V)
- Sensor 2 should change smoothly with pedal movement and correlate closely with Sensor 1 (no large jumps or frozen values)
- Maximum allowable difference between Sensor 1 and Sensor 2 usually small (check OEM spec), often
Diagnostic algorithm
- Retrieve all stored/related DTCs and freeze frame with a scan tool. Note conditions when code set. Clear codes and attempt to reproduce.
- With key ON (engine off), observe APP Sensor 1 and Sensor 2 voltages/percent on the scan tool. Note voltages at rest and then gradually depress the pedal while watching for smooth, proportional change.
- If Sensor 2 shows no signal, fixed value, or out-of-range voltage, visually inspect pedal connector and wiring for damage, corrosion or water intrusion. Repair any visible issues.
- Backprobe the pedal connector: verify VREF (~5V) present, proper sensor ground, and measure Sensor 2 signal voltage. If VREF or ground missing, trace to source and repair.
- Check continuity and resistance of Sensor 2 signal wire between pedal connector and PCM connector (battery disconnected). Repair open or high-resistance circuits.
- Check for short to 5V or to ground by measuring resistance from signal wire to VREF and to ground (with power removed). Repair any shorts.
- If wiring/connector tests are good but signal is invalid, replace the APP pedal assembly (contains Sensor 2) and retest.
- If code persists after sensor replacement and wiring checks, inspect PCM connector and grounds. Consider PCM as last resort—verify with OEM diagnostic procedures before replacement.
- After repairs, clear codes and verify proper operation by monitoring live data under normal conditions and confirming code does not return.
Likely causes
- Damaged harness between pedal and PCM (most common)
- Corroded/loose connector at APP pedal or PCM
- Failed APP Sensor 2 inside pedal assembly
- Short to ground or to VREF caused by nearby chafed wire
Fault status
Status
PCM detected an open, short, out-of-range or implausible signal on Accelerator Pedal Position Sensor 2 circuit. Fault may cause throttle to enter reduced-power mode until corrected.
Repair difficulty: Medium
Diagnostic time: 0.5-3.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email