P0371
Timing Reference High Resolution Signal A Too Many Pulses.
- Generic
- Powertrain
- Generic code
- Medium severity
How this code is built
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- 3
- AreaIgnition system or misfire
- 71
- FaultThe specific fault in that area
What it means
P0371 is the generic code for the high resolution timing reference signal 'A' showing too many pulses. The engine control unit counts the pulses from the crankshaft or camshaft timing reference and compares them with the expected count for each engine cycle. It saw more pulses than it should, which usually points to electrical interference or a damaged or faulty reference signal. Which sensor or wheel 'A' refers to depends on the engine and model.
Symptoms
- Engine misfiring or running roughly
- Intermittent stalling or cutting out
- Hesitation or loss of power
- Hard starting or extended cranking
- Malfunction indicator lamp on
- Erratic or flickering rev counter
Possible causes
- Damaged, loose or corroded wiring or connector on the crankshaft or camshaft position sensor circuitlikely
- Electrical interference on the sensor signal from poorly routed or damaged wiring, faulty ignition components or a poor earthlikely
- Faulty crankshaft or camshaft position sensor producing spurious pulseslikely
- Damaged, dirty or contaminated reluctor wheel or trigger wheel, such as metal debris, a missing or damaged toothpossible
- Incorrect sensor air gap or loose sensor mountingpossible
- Timing belt or chain wear, jumped timing or a loose trigger wheel affecting the signalrare
- Fault within the engine control unitrare
How to diagnose
- Read all stored and pending codes and the freeze frame data, noting engine speed, load and temperature when the fault set, and check for related crank or cam correlation codes.
- Check the manufacturer's information for which sensor and signal 'A' refers to on this engine, as it varies by model.
- Inspect the sensor wiring and connectors for chafing, water ingress, corrosion, bent pins and poor routing near ignition or charging wiring.
- Check the battery condition, charging voltage and engine earth connections, as poor power or earths can cause signal noise.
- Inspect the sensor for secure mounting, correct fitment, damage and metal debris on the tip, and check the air gap where it is specified.
- Inspect the reluctor wheel through the sensor aperture where accessible for damaged, missing or contaminated teeth.
- Use a live data view or oscilloscope to watch the sensor signal while cranking and running, looking for extra pulses, dropouts or noise, and wiggle-test the harness during the capture.
- Check the ignition system condition and, if the signal is clean at the sensor but wrong at the control unit, check the wiring continuity and insulation between them.
How to fix
- Repair or replace damaged wiring and connectors, and reroute the harness away from sources of interference.
- Replace the faulty crankshaft or camshaft position sensor once the signal fault is confirmed.
- Clean, repair or replace a contaminated or damaged reluctor wheel, following the manufacturer's procedure.
- Correct the sensor mounting and air gap, and repair any poor battery or earth connections.
- Correct the valve timing and replace worn timing components if a timing fault is confirmed.
- Only after all other causes are ruled out, diagnose and repair or replace the engine control unit as the manufacturer directs.
Can I keep driving?
The car may run, but stalling or misfiring can happen without warning, which is a safety risk in traffic. Limit driving to getting it to be diagnosed and repaired soon, and avoid it if the engine is stalling or running badly.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.