P0374–P0379 Timing Reference High Resolution Signal A No Pulses
The ECU has logged a fault on P0374. The definition below is the exact wording the standard uses for this code.
Can you drive it? The engine light will stay on and the car may run in a reduced-power mode. Read the freeze-frame data to see the conditions the fault was logged under.
Which code is which
Same fault, different cylinder or bank — diagnosed the same way. Several set together usually means one shared cause.
| Code | Definition | Severity |
|---|---|---|
P0374 | Timing Reference High Resolution Signal A No Pulses | Investigate soon |
P0379 | Timing Reference High Resolution Signal B No Pulses | Investigate soon |
The definition
P0374: Timing Reference High Resolution Signal A No Pulses.
P0374 is a powertrain code (the engine or gearbox), defined by the SAE standard - it means the same thing on any make of car, and any generic OBD-II reader will decode it.
What to check first
Cheapest and fastest checks first:
- Read the freeze-frame data stored with the fault - engine speed, load and temperature at the moment it logged tell you whether this happens cold, hot or under load.
- Check the connector at the part for corrosion, and that it is fully seated.
- Clear the code and see whether it returns, and under what conditions.
What actually causes this on a VAG
This one is blunt: the ECU saw no engine-position signal at all. Without it the ECU does not know where the crankshaft is, so it will not fire the injectors or the ignition - the usual symptom is an engine that cranks over healthily but does not start, or one that cut out while driving and would not restart. There is a free check that confirms it before you spend anything: watch the engine RPM reading on a scan tool while someone cranks the engine. Cranking briskly with the RPM sitting at zero means the crankshaft signal is not reaching the ECU, and that is the fault - not fuel, not spark, not the immobiliser. Note also that this code can be stored after a single stall and the car may run again afterwards, which means the signal is only being lost some of the time; in that case treat it as an intermittent hunt rather than a dead component. This is a generic industry code rather than VAG's own wording, so read it with software that shows the manufacturer text too.
Most likely causes, in order
- Connector unplugged, damaged or oiled up. The sensor sits in an awkward, dirty spot on many VAG engines and is easily disturbed. If the fault appeared straight after work near the bellhousing, starter, gearbox or sump, check that plug first - a disturbed or half-seated connector is far more often the answer than a part that happened to fail on the same day. Look for oil that has wicked into the plug body from a weeping seal, and for a pin pushed back in the housing.
- Broken wire between sensor and ECU. A single open circuit in the loom looks identical to a dead sensor from the driver's seat, and it is cheaper to test than to replace. Check the run for chafe points, previous repair joints and rodent damage before you buy anything.
- Failed sensor. These do simply die, sometimes suddenly and sometimes only once hot. It is not usually an expensive part, and on a no-start with this code it is the standard replacement once the plug and wiring have been checked. Fit a good-quality original-equipment or reputable-brand part - cheap no-name crankshaft sensors are a well-known cause of repeat no-starts, and a second failure costs far more in time and recovery than the sensor saved.
- Sheared or slipped toothed wheel. Uncommon, but if the wheel or the hub carrying it has moved, no sensor will read it. Suspect this only once the sensor and wiring have both checked out.
Worth knowing: Do not keep cranking a car that will not start on this code. You will not start it - with no position signal the ECU has nothing to time against - and you will overheat the starter motor and flatten the battery. That second one matters more than it sounds: once the battery is low, modules across the car start logging their own under-voltage faults, and you go from one clear fault to a screen full of noise that hides it. Check the sensor plug, confirm with the cranking RPM test above, then get the signal looked at properly.
Reading the code is the easy part
A code names the circuit that complained. What tells you why is watching the sensor behind it while the engine runs — and that is where a code reader stops and a diagnostic tool starts.
VAGPULSE reads every module in a VW, Audi, Skoda or SEAT — not just the engine — shows the live measuring blocks behind this fault, gives you the freeze-frame conditions it was logged under, and clears it once you have fixed it. It also does what a generic OBD reader cannot on a VAG: service resets, coding, adaptations, and Stage 1–3 flashing with your original file saved first.
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Common questions
What does P0374 mean?
P0374 means Timing Reference High Resolution Signal A No Pulses. It is logged when the ECU sees this circuit outside its expected operating window.
Can I drive with P0374?
The engine light will stay on and the car may run in a reduced-power mode. Read the freeze-frame data to see the conditions the fault was logged under.