P0372 Timing Reference High Resolution Signal A Too Few Pulses

P0372 indicates too few pulses in Timing Reference High Resolution Signal A. The controller is missing expected high-resolution timing events.

Code details

Generic OBD-II · P0

System: Ignition / Misfire
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not assume low fuel pressure or ignition failure when the timing reference signal is missing pulses.

Symptoms of P0372

Rough idle, shaking, or a stumble under acceleration.
A flashing check-engine light during an active misfire.
Power loss and higher fuel consumption.

Common causes of P0372

Worn spark plugs, ignition coils, or plug wires.
Fuel-delivery problems — injectors, pressure, or a lean/rich mixture.
Vacuum leaks, low compression, or a mechanical fault in that cylinder.

Useful checks before replacing parts

Check high-resolution signal A pulse count, RPM dropouts, crank and cam sync, freeze-frame RPM, and whether the concern happens during cranking or running.
Inspect for weak sensor output, excessive air gap, damaged trigger wheel teeth, loose connectors, open signal wiring, and poor power or ground.
Use scope capture to confirm whether pulses disappear consistently or only under heat, vibration, or load.

Related OBD-II codes

These nearby ignition / misfire entries can help compare wording and pin down the fault area.