P0373 code meaning
Timing Reference High Resolution Signal A Intermittent/Erratic Pulses
Powertrain system Generic code P03xx codes Check engine light
What P0373 means
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. P0373 means signal A delivers pulses with erratic spacing or with occasional dropouts – typical of a loose contact or electrical interference. No manufacturer document available to us uses P0373: 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.
P0373 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyHard
- Typical labor1 to 6 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0373
- Check engine light on
- Loss of power (limp-home fuelling)
- Rough running, hard starting, smoke
Common causes of P0373
- Most likelySensor faulty or dirty
- PossibleLoose contact or interference in the signal wire
- PossibleSensor disc or tone wheel damaged
- Less likelyEngine module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
High resolution timing sensorInjection pumpSensor wiringEngine control module
What each part of P0373 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 3 | Area: ignition system or misfire. |
| 73 | The exact fault in that area. |
What to do next
- Note P0373 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0373
What does P0373 mean?
P0373 means "Timing Reference High Resolution Signal A Intermittent/Erratic Pulses". 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. It is a generic code, so it means the same on every make.
Is it safe to drive with P0373?
Drive gently and only to a workshop. With P0373 the car can go into limp mode (reduced power) to protect itself.
Will P0373 fail an emissions test?
Yes, it can. P0373 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0373 to fix?
Difficulty: hard. A typical repair takes 1 to 6 hours of work. This is a job for a workshop.
Will P0373 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.