DTC 143 — Incorrect Number of CMP Signal Transitions Per Cam Revolution — International DT466E
DTC 143 on International DT466E (1996–2003) indicates the ECM is not seeing the expected camshaft position (CMP) signal pattern. CMP faults (DTC 143–145) can…
What it means
The ECM is not seeing the expected camshaft position (CMP) signal pattern. On the DT466E, CMP faults (DTC 143–145) can cause no-start or stalling.1
Most likely causes
- Failing CMP sensor — Sensor output is degraded or intermittent, producing an incorrect number of transitions per cam revolution. Typical on this platform for DTC 143.1
- CMP wiring or connector fault — Damaged, corroded, or loose wiring/connector to the CMP sensor alters the signal pattern.1
- Incorrect air gap / sensor mounting — Sensor-to-target air gap out of specification changes signal amplitude and transition count.1
- Electrical noise on CMP circuit — Noise on the CMP signal can corrupt transition counting. CMP signal noise is a related CMP fault on this platform.2
- Related CMP fault conditions — DTC 145 indicates no CMP signal while ICP rises during cranking, a classic no-start on this HEUI engine.3
How to diagnose
- Verify the code with a scan tool or flash codes; DTC 111 = no faults on Navistar three-digit system.
- Inspect CMP sensor connector and wiring for damage, corrosion, or poor routing; repair as needed.
- Check CMP sensor mounting and air gap per service specifications; correct sensor position.
- Monitor CMP signal while cranking with a lab scope or scan tool to confirm transition count per cam revolution.
- Check related CMP codes 144 and 145; noise or inactive signal points to wiring/ground or sensor failure.
- If hard/no start persists, confirm HEUI basics: ICP builds during cranking; low ICP causes hard/no start on this engine.
Parts and tools you may need
- Digital multimeter
- Lab scope
- Navistar-compatible scan tool
- Basic hand tools
- Dielectric grease
- Wiring repair kit
Tools you’ll need
- OBD-II scan tool — Reads and clears DTC 143 and related CMP codes 144/145 on the DT466E and verifies flash code 111 for no faults.
- digital multimeter — Checks CMP sensor supply voltage, ground continuity, and wiring integrity for opens/shorts/corrosion.
- lab scope — Monitors the CMP signal pattern while cranking to confirm correct transition count per cam revolution.
- feeler gauge — Verifies and sets the CMP sensor air gap to service specification for proper signal generation.
Rough cost and difficulty
| Likely repair | Parts | Shop labor | Who usually does it |
|---|---|---|---|
| ECM/PCM software update | — | 0.5–1.5 hrs | Shop |
| Shop diagnosis | — | 1–2 hrs | Shop |
| Wiring or connector repair | $10–$100 | 1–4 hrs | DIY with tools and a manual |
| Crankshaft or camshaft position sensor | $40–$200 | 0.5–2 hrs | DIY with tools and a manual |
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 the engine cranks but will not start, or stalls intermittently, have a qualified diesel technician diagnose the CMP circuit and HEUI system. Do not attempt high-pressure oil system service without proper training and safety equipment.
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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