Faulty or failing crankshaft position sensor (heat-related dropouts are common); Damaged, chafed or corroded wiring, or poor connector contact in the sensor circuit; Damaged, dirty or loose reluctor or trigger wheel, or metallic debris on the sensor tip; Incorrect sensor air gap or loose sensor mounting; Electrical interference or poor earth or power supply to the sensor; Mechanical timing fault, such as a stretched or jumped timing chain or belt, affecting crank and cam correlation; Fault within the engine control unit.

P0373

Timing Reference High Resolution Signal A Intermittent/Erratic Pulses.

Generic
Powertrain
Generic code
High severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
3: AreaIgnition system or misfire
73: FaultThe specific fault in that area

What it means

P0373 is the generic code for an intermittent or erratic pulse signal from the timing reference high resolution signal 'A', which is normally the crankshaft position sensor circuit. The engine control unit saw pulses that dropped out, appeared unexpectedly or did not match the pattern it expects while the engine was turning. Exactly which sensor and circuit 'A' refers to depends on the model and engine, so check the manufacturer's data.

Symptoms

Engine cranks but starts intermittently or hangs on cranking
Engine stalls or cuts out suddenly, often when warm
Misfires, hesitation or rough running
Rev counter flickering, dropping to zero or behaving erratically
Loss of power or poor acceleration
Malfunction indicator lamp on, possibly with misfire codes stored

Possible causes

Faulty or failing crankshaft position sensor (heat-related dropouts are common)likely
Damaged, chafed or corroded wiring, or poor connector contact in the sensor circuitlikely
Damaged, dirty or loose reluctor or trigger wheel, or metallic debris on the sensor tippossible
Incorrect sensor air gap or loose sensor mountingpossible
Electrical interference or poor earth or power supply to the sensorpossible
Mechanical timing fault, such as a stretched or jumped timing chain or belt, affecting crank and cam correlationrare
Fault within the engine control unitrare

How to diagnose

Read all stored and pending codes and the freeze frame data to see engine speed, temperature and load when the fault set; note any cam sensor or misfire codes
Check for relevant technical service bulletins and software updates for the model and engine
Visually inspect the crank sensor, its connector and wiring for damage, oil contamination, chafing, heat damage or corrosion
Wiggle-test the harness and connector with the engine running or cranking while watching live engine speed data for dropouts
Check the sensor is secure and the tip is clean and free of metal debris, and check the air gap where adjustment is specified
Inspect the reluctor or trigger wheel for damaged, missing or loose teeth where it can be accessed
Check the sensor supply, earth and signal using a scope or multimeter against the manufacturer's specification, comparing crank and cam waveforms
Check mechanical timing correlation if the electrical checks pass and the signals look out of step

How to fix

Replace the crankshaft position sensor if its signal is erratic or drops out, especially when it fails once warm
Repair or replace damaged wiring and clean or renew faulty connectors and terminals
Clean or replace the sensor mounting, and correct the air gap where the design allows adjustment
Replace a damaged reluctor or trigger wheel, or correct its fitment
Correct the mechanical timing and replace worn chain or belt components if correlation is out
Update or replace the engine control unit only if a fault is confirmed after all other causes are eliminated, following the manufacturer's procedure

Can I keep driving?

High severity

Avoid driving until it is diagnosed, as the engine may stall without warning, which is unsafe, particularly in traffic or at junctions. If the cause is a mechanical timing fault, continued driving risks serious engine damage.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.