DTC 131 — Accelerator Pedal Position Signal Out of Range – Low — International DT466E
Diagnostic reference for Navistar three-digit code 131 on International DT466E (1996–2003).
What it means
Accelerator pedal position (APS) signal voltage is below its valid range. On this platform the engine may only idle.1
Most likely causes
- Pedal sensor internal fault or worn APS potentiometer causing low voltage output — A failing APS potentiometer can produce a signal below the ECM’s valid range, leading to a low-range fault and limited throttle response.1
- Wiring open or high resistance in the APS signal circuit to the ECM — An open or corroded signal wire raises resistance and pulls the APS voltage low, setting the low-range code.1
- Short to ground in the APS signal or reference circuit — A short to ground forces the APS voltage toward zero, which the ECM interprets as out of range low.1
- Faulty idle validation switch (IVS) interaction with APS — The DT466E uses an APS with an IVS; disagreement or IVS wiring faults can contribute to pedal signal anomalies and limited throttle.2
How to diagnose
- Verify the code with a scan tool or flash codes; confirm DTC 131 is active and note freeze-frame conditions.
- Inspect the accelerator pedal assembly and wiring harness for chafing, corrosion, loose connectors, and moisture ingress at the pedal and ECM bulkhead.
- Check APS reference voltage and signal voltage at the sensor connector with key on, engine off; compare to service specifications and look for voltage below the valid range.
- Wiggle-test the APS harness while monitoring live APS voltage to reveal intermittent opens or shorts.
- Inspect the idle validation switch (IVS) operation and its wiring; a disagreement between APS and IVS can affect pedal signal interpretation.
- If voltages are out of range, disconnect the sensor and test the harness for shorts to ground and opens; repair wiring as needed, then retest.
- Replace the accelerator pedal sensor assembly if electrical tests pass but the low-range signal persists.
Parts and tools you may need
- Digital multimeter
- Scan tool capable of Navistar three-digit codes
- Wiring diagram for DT466E APS/IVS circuit
- Replacement accelerator pedal position sensor assembly
Tools you’ll need
- OBD-II scan tool — Reads and clears DTC 131 and provides live APS voltage and freeze-frame data to confirm the low-range fault.
- Digital multimeter — Measures APS reference, signal, and ground voltages at the pedal connector to verify low voltage and detect shorts or opens.
- Wiring test light or breakout box — Allows wiggle-testing of the APS harness while monitoring voltage to find intermittent opens or shorts to ground.
- Inspection mirror and flashlight — Enables visual inspection of the pedal assembly, harness chafing, corrosion, and moisture at the ECM bulkhead.
Rough cost and difficulty
| Likely repair | Parts | Shop labor | Who usually does it |
|---|---|---|---|
| Wiring or connector repair | $10–$100 | 1–4 hrs | DIY with tools and a manual |
| Accelerator pedal position sensor | $80–$300 | 0.3–1 hrs | Easy DIY |
Typical US independent-shop figures; labor runs about $140–$200 per hour (dealers charge more). Confirm the diagnosis before buying parts.
When to see a pro
If wiring faults are found in the ECM bulkhead or the code returns after sensor replacement, have a qualified diesel technician inspect the ECM connectors and perform a pin drag test. Do not attempt high-pressure oil system service for this code.
Check for recalls
Recalls are tied to your truck’s VIN, so check yours directly: enter the VIN at NHTSA’s recall lookup. Open safety recalls are repaired free at a dealer.
Sources
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