DTC 241 — Injection Control Pressure Regulator OCC Self Test Failed — International DT466E
DTC 241 on International DT466E (1996–2003) indicates the ECM’s output circuit check for the injection pressure regulator (IPR) failed. The code is a Navistar…
What it means
The injection pressure regulator (IPR) output circuit check failed. The ECM cannot verify control of the IPR valve circuit during its self-test. On the DT466E this is a Navistar three-digit code for the HEUI system; the IPR valve, its coil, connector or wiring is suspect.1
Most likely causes
- IPR valve coil or internal electrical fault — The IPR solenoid coil is open, shorted or degraded so the ECM’s output circuit check fails. Typical on this platform for DTC 241.1
- IPR valve electrical connector or terminals damaged/corroded — Connector pins are corroded, backed out or oil-contaminated, causing an intermittent or open circuit to the IPR.1
- Wiring harness chafing, short or open between ECM and IPR — Chafed or broken wiring in the engine harness creates an open/short on the IPR control circuit, preventing the ECM self-test from passing.1
How to diagnose
- Verify the code with a scan tool or flash code read; confirm DTC 241 is present and active. Navistar three-digit codes are read by flash counts or scan tool.
- Inspect IPR valve connector for oil intrusion, corrosion, bent or backed-out pins; disconnect, clean and inspect terminals. Typical IPR circuit fault for DTC 241.
- Check IPR valve coil resistance per service spec and compare to known-good values; replace IPR if out of spec. Typical IPR coil fault for DTC 241.
- Inspect wiring harness from ECM to IPR for chafing, heat damage, or shorts to ground/power; perform continuity and isolation tests. Typical wiring fault for DTC 241.
- Clear codes, command IPR duty cycle with scan tool and monitor IPR feedback; re-run ECM self-test to confirm circuit passes. Typical verification for DTC 241.
Parts and tools you may need
- Digital multimeter
- Scan tool capable of Navistar three-digit codes and IPR command
- Contact cleaner and dielectric grease
- Replacement IPR valve (OEM spec)
- Wiring repair kit / terminals
Tools you’ll need
- Navistar-compatible scan tool — Reads and clears DTC 241 and commands IPR duty cycle to verify ECM control during self-test.
- Digital multimeter — Measures IPR coil resistance and checks continuity/isolation of the IPR circuit wiring to ECM.
- Terminal release tool set — Safely disconnects and inspects IPR connector terminals for corrosion, oil intrusion, or damage without harming pins.
- Inspection mirror and LED flashlight — Allows visual inspection of the IPR harness routing for chafing, heat damage, and hard-to-see areas near the valve.
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 |
| IPR (injection pressure regulator) valve | $70–$300 | 0.5–2 hrs | DIY with tools and a manual |
| Engine wiring harness section | $100–$500 | 2–5 hrs | Shop |
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 IPR circuit tests good but the code returns, have a qualified diesel technician inspect the ECM outputs and harness integrity. Do not attempt repairs on 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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