P0372Timing Reference High Resolution Signal A Too Few Pulses
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- Some diesel systems give the injection control a finely divided angle signal in addition to the normal reference signal – the high resolution signal – for precise injection timing and metering. P0372 means signal A delivers fewer pulses than expected within the reference window – marks are missing, for example from a weak signal, a dirty sensor disc or too large an air gap; on GM's 6.5-litre diesel the nominal ratio is 64 ± 4 pulses per cam pulse. No manufacturer document available to us uses P0372: GM's 6.5-litre diesel (optical sensor in the injection pump) reports all faults of its high resolution track under P0370 and the Duramax LB7 uses only P0370 and P0374. The description therefore follows the J2012 name, GM's description of the signal and CARB's monitoring requirement for crank angle sensors. Typically the engine loses power and runs roughly.
- What you may notice
- Check engine light on
- Loss of power (limp-home fuelling)
- Rough running, hard starting, smoke
- Likely causes
- LikelySensor faulty or dirty
- PossibleLoose contact or interference in the signal wire
- PossibleSensor disc or tone wheel damaged
- RareEngine module
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €150 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.