P1285

Code

CHRYSLER P — Powertrain

Accelerator Pedal Position (APP) Sensor 3 Circuit

Brand: CHRYSLER

Type: P — Powertrain

Views: UK: 35 EN: 62 RU: 38

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Page language: EN

Causes

Faulty accelerator pedal assembly (APP sensor 3)
Damaged, corroded or loose wiring or connector at the pedal harness
Short to battery or ground in the signal wire
Poor ground or reference voltage (5V) supply from ECM
Water intrusion or contamination in connector
ECM internal fault (rare)

Symptoms

Malfunction Indicator Lamp (MIL) or CEL illuminated
Reduced engine power or 'limp' mode engaged
Delayed or inconsistent throttle response
Cruise control disabled
Possible jerky idle or unexpected throttle behavior

What to check

Read and record freeze frame and all stored codes with a scan tool
Visually inspect pedal connector and wiring harness for damage, corrosion, water
Wiggle test wiring and connector while monitoring live APP sensor data
Measure reference voltage and ground at pedal connector with key ON (engine OFF)
Backprobe signal wire and verify voltage changes smoothly as pedal is moved
Compare sensor 3 signal to sensor 1 and 2 signals (if available) for consistency

Signal parameters

Reference voltage: typically ~5.0 V (key ON, engine OFF)
Signal voltage range: typically ~0.5 V (closed) to ~4.5 V (wide open) and should change smoothly with pedal movement
Sensor 3 should track similarly to sensor 1 and sensor 2 (monotonic increase without dropouts)
No short to battery (near 12 V) or short to ground (0 V) on the signal wire

Diagnostic algorithm

Use a scan tool to read P1285 and any related APP/throttle codes (P0120-P0223 or manufacturer-specific codes). Note freeze frame data and ignition cycles.
Visually inspect the accelerator pedal assembly, connector and wiring for damage, corrosion, or moisture. Repair or secure any damaged wiring.
With key ON (engine OFF), backprobe the pedal connector: verify reference ~5 V, good ground, and check signal pin voltage. If reference or ground is missing, trace to the ECM.
Operate the pedal and observe the signal voltage on sensor 3. It should move smoothly and be within expected range. If the signal is stuck, jumps, reads out-of-range or is 0 V/12 V, suspect wiring or sensor.
Perform a wiggle test on harness and connector while watching live data for intermittent faults. Repair any intermittent wiring faults.
Measure continuity/resistance from pedal connector pins to corresponding ECM pins. Repair any open/shorted conductors.
If wiring and connectors are good but the sensor signal is incorrect, replace the accelerator pedal assembly. Reconnect and clear codes.
After repair, erase codes, run self-tests, and perform a road test to confirm the code does not return.
If fault persists with good wiring and new pedal, consider ECM diagnosis or replacement as a last step (rare).

Likely causes

Connector push-fit loose or corroded at pedal
Broken/shorted signal wire due to chafing near hinge or firewall
Failed pedal sensor (wear or internal short)
Open reference or ground circuit to the pedal sensors

Fault status

⚠️ Status

MIL ON; DTC stored. May also trigger reduced engine power / limp-home mode and disable cruise control until fault is resolved.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours

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P1285 — Accelerator Pedal Position (APP) Sensor 3 Circuit