P0374
Timing Reference High Resolution Signal A No Pulses
Ignition / timing reference
Generic OBD-II
High
What it means
P0374 means the ECM is receiving no pulses from the high-resolution timing reference signal A — the precise crank/cam-based signal it uses to time spark and fuel. Without it the ECM can't accurately time the engine, which commonly causes hard starting, stalling, or a no-start, plus rough running when it does run.
High
Can I keep driving? Don't rely on the car — a missing timing signal can stall the engine or stop it starting; get it fixed before driving far.
Common symptoms
What you'll notice
- Check-engine light on
- Hard starting or a no-start
- Stalling
- Rough running and reduced power when it does run
Common causes
Most likely first
- Open or shorted wiring/connector on the timing-reference circuitLikely
- Failed crankshaft position sensorCommon
- Failed camshaft position sensorCommon
- Damaged reluctor/tone ringLess often
- ECM fault (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and inspect the timing-reference sensor connectors and wiring for an open or short.
- Check the crankshaft and camshaft sensor signals with a scope.
- Inspect the reluctor/tone ring for damage or contamination.
- Replace the failed sensor.
- Verify ECM power and grounds if the signal circuit is intact. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0374?+
No — an unreliable timing signal can stall you without warning, so fix it before relying on the car.
Can I just clear P0374?+
You can, but it returns immediately if the circuit is still open.
Related codes
Often seen with P0374
Read & clear P0374 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