Engine

P0372 — Timing Reference High Resolution Signal A: Too Few Pulses

Severity: medium Drive with care, to a shop

What P0372 means

The engine control module counts pulses from a high resolution timing reference signal, normally produced by a crankshaft or camshaft position sensor reading a toothed wheel. P0372 sets when fewer pulses arrive than expected during the monitoring period. Without an accurate signal, the ECM cannot time ignition and fuel injection correctly.

Symptoms

  • Check Engine light on
  • Hard starting or no start
  • Rough idle or misfires
  • Loss of power and hesitation
  • Engine stalling while driving

Possible causes

  1. Failed crankshaft or camshaft position sensor
  2. Damaged wiring, poor connector contact, open circuit or short to ground
  3. Dirty, damaged or shifted reluctor (tone) wheel
  4. Mechanical timing problem such as a stretched chain or slipped belt
  5. Incorrect sensor air gap or loose sensor mounting
  6. ECM input circuit fault (rare)

How to diagnose

  1. Scan for codes and freeze frame data, and note any other CKP/CMP or misfire codes
  2. Check whether the ECM shows RPM while cranking
  3. Inspect the sensor, connector and harness for oil, cracks, corrosion and chafed insulation
  4. Test sensor power, ground and signal wires with a multimeter against the wiring diagram
  5. Scope the sensor signal and look for missing or irregular pulses
  6. Remove the sensor and inspect the tone wheel for damage, debris or metal shavings
  7. Check sensor air gap and mounting
  8. Verify mechanical timing, including belt or chain condition and alignment marks

Common fixes

  • Replace the crankshaft or camshaft position sensor
  • Repair wiring or replace a damaged connector
  • Clean, realign or replace the tone wheel
  • Correct mechanical timing issues by replacing the chain or belt and setting the marks
  • Repair or replace the ECM only after everything else is ruled out

Questions and answers

What does P0372 mean?

The ECM is getting too few pulses from a timing reference signal, usually from the crankshaft or camshaft sensor. That disrupts ignition and fuel timing.

Can I drive with P0372?

Only briefly, and only if the engine runs smoothly. It may stall without warning, so repair it soon.

Which sensor should I replace for P0372?

Do not guess. Check the wiring, connector and tone wheel first, then replace the sensor if its signal is faulty.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.