Faulty crankshaft or camshaft position sensor producing no signal; Damaged, chafed or corroded wiring or connector to the sensor; Damaged, contaminated or incorrectly fitted reluctor or trigger wheel; Incorrect air gap or loose sensor mounting; Low battery voltage or poor power or earth supply to the sensor or control unit; Mechanical timing fault such as a slipped or broken timing belt or chain; Faulty engine control unit.

P0374

Timing Reference High Resolution Signal A No 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
74: FaultThe specific fault in that area

What it means

P0374 is the generic code for 'Timing Reference High Resolution Signal A No Pulses'. The engine control unit expects a high resolution timing signal, normally from a crankshaft or camshaft position sensor circuit, and has detected no pulses on it. How this signal is produced and which sensor circuit is 'A' depends on the vehicle and engine, so check the manufacturer's information for the specific model.

Symptoms

Engine cranks but will not start, or starts with difficulty
Engine stalls unexpectedly or cuts out while driving
Rough running, misfires or hesitation
Rev counter drops to zero or behaves erratically
Malfunction indicator lamp on
Limp mode or reduced power on some models

Possible causes

Faulty crankshaft or camshaft position sensor producing no signallikely
Damaged, chafed or corroded wiring or connector to the sensorlikely
Damaged, contaminated or incorrectly fitted reluctor or trigger wheelpossible
Incorrect air gap or loose sensor mountingpossible
Low battery voltage or poor power or earth supply to the sensor or control unitpossible
Mechanical timing fault such as a slipped or broken timing belt or chainrare
Faulty engine control unitrare

How to diagnose

Read all stored and pending codes and record the freeze frame data, noting engine speed, coolant temperature and battery voltage when the code set
Check for other position sensor or misfire codes that point to the affected circuit
Inspect the sensor wiring and connectors for damage, oil contamination, water ingress, corrosion and loose pins
Check battery condition and charging voltage, and confirm the sensor has the correct supply and earth
Check live data for engine speed while cranking; a missing RPM reading points to a signal fault
Inspect the sensor for debris, damage and correct mounting and air gap, and check the trigger wheel for damage or missing teeth
Test the sensor signal with an oscilloscope against the manufacturer's specification for the model
If the signal is absent or erratic and the electrics are good, verify mechanical timing and then check the control unit's supply, earths and wiring

How to fix

Replace the faulty crankshaft or camshaft position sensor
Repair or replace damaged wiring and clean or renew corroded connectors
Replace or correctly refit a damaged trigger wheel and set the sensor air gap where adjustable
Restore a sound battery, power and earth supply
Correct the engine timing and repair any related mechanical damage
Repair or replace the control unit only after all other causes are ruled out, with any required coding or programming

Can I keep driving?

High severity

Avoid driving the car, as it may stall without warning and cause a loss of power steering assistance and braking assistance. If the engine will not start, have it recovered and repaired.

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