P0374Timing Reference High Resolution Signal A No 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. By its J2012 name P0374 means signal A delivers no pulses at all although the engine turns. GM's 2004 Duramax LB7 uses the code differently, for a plausibility fault: the injector driver module evaluates the 57X crank signal and reports it as implausible over CAN; from 60 rpm, 100 of 120 samples of 31.6 ms set the code, in the first trip. GM's 6.5-litre diesel with the optical sensor in the injection pump reports all faults of its high resolution track under P0370. Without the fine signal the module falls back to coarser timing, so the engine loses power and may run roughly or start poorly.
- What you may notice
- Check engine light on
- Loss of power (limp-home fuelling)
- Rough running, hard starting, smoke
- Likely causes
- LikelySensor (pump or crankshaft) faulty or dirty
- PossibleLoose contact or interference in the signal wire
- PossibleSensor disc or tone wheel damaged
- RareInjector driver module or engine 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.