DTC 124 — Injection Control Pressure Signal Out of Range – Low — International DT466E
DTC 124 on the International DT466E (1996–2003) is a Navistar three-digit flash code for the HEUI injection system. It indicates the ECM is seeing an ICP…
What it means
On the DT466E, DTC 124 means the ECM is reading the Injection Control Pressure (ICP) sensor signal voltage below its valid range. The code is a sensor/circuit fault for the HEUI system; it does not by itself confirm actual low injection control pressure.1
Most likely causes
- ICP sensor failed internally, producing a low output voltage — A failed ICP sensor can pull the signal low and set DTC 124. Typical on this platform is a failed sensor.1
- ICP sensor signal circuit open or shorted to ground — An open or shorted wiring path to the ICP sensor signal can cause the ECM to see a voltage below range. Typical on this platform is an open/shorted wiring fault.1
- Oil contamination in the ICP sensor connector — Engine oil can wick into the ICP connector and corrupt the signal, leading to a low reading. Typical on this platform is oil in the connector.1
How to diagnose
- Verify the code with a scan tool or flash codes and confirm the engine is a DT466E HEUI system with ICP sensor and IPR valve.
- Inspect the ICP sensor and its connector for oil intrusion, damaged pins, corrosion, or loose connection; clean and dry as needed.
- Check the ICP sensor signal circuit for continuity to the ECM and for shorts to ground or to power; repair wiring faults if found.
- Monitor ICP sensor voltage with a scan tool during key-on and cranking; compare to expected range and look for a stuck low reading consistent with a sensor or circuit fault.
- If the circuit tests good, replace the ICP sensor and retest; a failed sensor is typical for this code on this platform.
Parts and tools you may need
- Digital multimeter
- Scan tool capable of Navistar three-digit flash codes
- Basic hand tools for sensor removal
- Dielectric grease
- Clean shop towels
Tools you’ll need
- OBD-II scan tool — Reads DTC 124 and monitors ICP sensor voltage during key-on and cranking to confirm a stuck low reading.
- Digital multimeter — Checks ICP sensor signal circuit continuity to the ECM and detects shorts to ground or power.
- Inspection mirror — Allows visual inspection of the ICP sensor and connector for oil intrusion, corrosion, or damaged pins.
- Contact cleaner — Cleans oil contamination from the ICP sensor connector before electrical testing.
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 |
| ICP (injection control pressure) sensor | $60–$200 | 0.5–1.5 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 code returns after sensor and wiring checks, or if actual low injection control pressure symptoms appear (hard/no start, low power), have a qualified diesel technician evaluate the high-pressure oil system. Do not service high-pressure oil components 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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