What are the common causes of P0373?

A signal A connector that loses contact with vibration. A harness worn through near a moving part. A signal A sensor failing as it heats up. Debris that shifts on the signal A ring. A corroded signal A sensor ground.

Wiggle test the signal A harness with a scope attached. Check the harness near moving parts for rub through. Watch signal A as the engine warms up. Clean the signal A sensor and ring. Replace the signal A sensor if the signal drops out. Clear the code and retest.

P0373

Timing Reference High Resolution Signal A Intermittent/Erratic Pulses

System: Ignition and misfire (P code)
Lamp: Check Engine Light
Category: Powertrain - Ignition

What it means

P0373 means Timing Reference High Resolution Signal A Intermittent/Erratic Pulses.

Check these first

A signal A connector that loses contact with vibration
A harness worn through near a moving part
A signal A sensor failing as it heats up
Debris that shifts on the signal A ring
A corroded signal A sensor ground

What to do next

Wiggle test the signal A harness with a scope attached
Check the harness near moving parts for rub through
Watch signal A as the engine warms up
Clean the signal A sensor and ring
Replace the signal A sensor if the signal drops out
Clear the code and retest

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Updated

Generic SAE J2012 definition. Last updated 2026-10-10.