P0373
Timing Reference High Resolution Signal A Intermittent/Erratic Pulses
Ignition / timing reference
Generic OBD-II
High
What it means
P0373 means the high-resolution timing-reference signal — the precise crank/cam pulse the computer uses to set spark and injection timing — is arriving erratically or with missing pulses. That upsets engine timing, so the car can misfire, stumble, stall, or fail to start. It usually traces to the timing sensor, its wiring, or a damaged reluctor wheel.
High
Can I keep driving? Unreliable — erratic timing pulses can cause misfires, stalling, or a no-start at any time. Have it diagnosed before driving far.
Common symptoms
What you'll notice
- Check-engine light on
- Misfires, stumbling, or surging
- Intermittent stalling or hard/no-start
- Reduced power and rough running
Common causes
Most likely first
- Faulty timing-reference (high-resolution) sensorLikely
- Faulty crankshaft or camshaft sensor feeding the timing signalCommon
- Damaged, chafed, or shorted signal wiringCommon
- Damaged crank/cam reluctor ring or tone wheelLess often
- Failed ECM (rare — check sensors and wiring first)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data to capture when the erratic pulses appear.
- Inspect the sensor connectors and harness for chafing, corrosion, or loose pins.
- Check the reluctor/tone wheel for damaged teeth, debris, or excessive runout.
- Scope the crank and cam signals while cranking and running to spot the dropout.
- Replace the high-resolution timing-reference sensor if its pulses are erratic, then clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0373?+
Not recommended. Erratic timing pulses can cause sudden misfires or stalling, and the engine may not restart. Diagnose it before relying on the car.
Can I just clear P0373?+
It will return whenever the erratic signal recurs. The sensor, wiring, or reluctor ring must be repaired first.
Related codes
Often seen with P0373
Read & clear P0373 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX