Faulty high-resolution timing sensor (camshaft or distributor sensor); Damaged or corroded wiring or connector at the sensor; Failed reluctor wheel or shutter inside the distributor; Open or shorted signal circuit between sensor and ECM; Defective ECM (rare but possible); Mechanical timing issue such as a jumped timing belt or chain; Poor ground connection for the sensor or ECM

DTC codes / P03xx · Ignition system and misfire / P0374

P0374Timing Reference High Resolution Signal 'A' No Pulse

Q: What does code P0374 mean?

Timing Reference High Resolution Signal 'A' No Pulse. P0374 means the engine control module (ECM) is not receiving a valid high-resolution timing reference pulse from the camshaft or distributor sensor circuit. The ECM uses this signal to precisely synchronize fuel injection and ignition timing, so a missing pulse forces it to rely on backup strategies or default timing.

P0374 means the engine control module (ECM) is not receiving a valid high-resolution timing reference pulse from the camshaft or distributor sensor circuit. The ECM uses this signal to precisely synchronize fuel injection and ignition timing, so a missing pulse forces it to rely on backup strategies or default timing.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaIgnition system and misfire

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Engine may crank but fail to start, or start after a long crank
Rough idle or misfire, especially when the engine is cold
Reduced engine power or limp mode
Poor fuel economy and increased emissions
Intermittent stalling or hesitation during acceleration

Common causes, most likely first

Faulty high-resolution timing sensor (camshaft or distributor sensor)
Damaged or corroded wiring or connector at the sensor
Failed reluctor wheel or shutter inside the distributor
Open or shorted signal circuit between sensor and ECM
Defective ECM (rare but possible)
Mechanical timing issue such as a jumped timing belt or chain
Poor ground connection for the sensor or ECM

How to diagnose and fix it

Scan all modules for stored and pending codes, and record freeze-frame data
Inspect the sensor and its connector for physical damage, corrosion, or loose pins
Check the sensor signal with an oscilloscope or a multimeter to confirm pulse presence
Verify wiring continuity and resistance between the sensor and ECM
Test the reluctor wheel or distributor shutter for damage or debris
Replace the faulty sensor if tests indicate failure
Clear codes and perform a road test to confirm the repair

What a missing pulse really tells you

A missing high-resolution pulse often results from a dirty or damaged reluctor wheel rather than a failed sensor, so visual inspection is critical.
Intermittent P0374 codes can be caused by a loose connector that only loses contact during engine vibration or temperature swings.
Some vehicles use the high-resolution signal for misfire detection, so a fault can set P0374 without any driveability complaint.
A failed crankshaft position sensor can sometimes cause a P0374 code if the ECM uses both signals for timing correlation.
After replacing the sensor, the ECM may require a relearn procedure to synchronize the new signal.

Can I keep driving with P0374?

If the engine starts and runs smoothly, you can drive cautiously to a repair shop, but avoid heavy acceleration or long trips. If the engine stalls, misfires badly, or fails to start, stop driving and have the vehicle towed to prevent further damage.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.