P0372
UniversalTiming Reference High Resolution Signal A Too Few Pulses
The engine control system detects fewer pulses than expected from the high-resolution timing reference signal A. This signal helps the system track engine timing. If it is unreliable, the engine may run poorly, stall, or fail to start, though some vehicles may show no obvious symptoms. The code identifies a detected signal condition, not proof that a particular part has failed.
⚠️ Before You Begin (Safety First)
If the engine stalls, runs very roughly, or cannot be relied on to keep running, avoid driving and arrange a safe inspection or tow. Do not work near moving engine parts while the engine is running.
Common Symptoms
- The check-engine light may be on because the control system has detected too few timing-reference pulses.
- The engine may crank but fail to start if the timing signal is too weak or incomplete for the system to establish timing.
- The engine may run roughly, hesitate, or lose power if timing information becomes unreliable.
- The engine may stall if the signal drops out while running.
- There may be no noticeable symptoms if the signal problem is intermittent or does not disrupt engine operation.
Common Causes
- A fault in the component or circuit that produces or carries timing reference signal A may result in missing pulses.
- A loose, damaged, corroded, or poorly connected connector may interrupt the signal.
- Damaged wiring, a short, or an open circuit may prevent some pulses from reaching the control system.
- A damaged or contaminated signal target, where used, may interfere with pulse generation.
- Electrical interference or a control-system fault may affect the signal or its interpretation.
Diagnostic Steps
- Note whether the engine starts, runs roughly, loses power, or stalls, and whether the code returns after clearing; these observations help describe whether the signal problem is persistent or intermittent.
- With the engine off, inspect accessible wiring and connectors associated with the timing reference signal for looseness, visible damage, corrosion, or contamination.
- Check for other stored codes and record them before clearing anything; related codes may help narrow down whether the problem affects a shared circuit or system.
- Avoid probing unidentified terminals or replacing parts based on the code alone. Use model-, year-, and engine-specific service information, or ask a qualified technician to test the signal.
When to Call a Professional
Use vehicle-specific service information to identify signal A and its circuit. Check scan data and inspect the relevant wiring and connectors; electrical testing or an oscilloscope may help determine whether pulses are missing at the source or lost along the circuit. Confirm the fault before replacing any component.
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Commonly Asked Questions
Does P0372 prove that a sensor needs replacement?
No. It reports too few pulses in timing reference signal A. Wiring, connectors, the signal-producing component, a signal target where used, interference, or a control-system issue may also be involved.
Can I keep driving with this code?
It depends on how the engine behaves. If it stalls, runs very roughly, or loses power, stop driving when safe and arrange an inspection. Even with no obvious symptoms, have the cause diagnosed.
Why might the engine still run if pulses are missing?
The signal problem may be intermittent or may not disrupt engine operation enough to cause an immediate stall. A stored code can remain even when symptoms are not noticeable.
What helps distinguish a signal-source problem from a wiring problem?
A technician can inspect the circuit and compare the signal at relevant points using vehicle-specific procedures. Scan data and, where appropriate, waveform testing can help identify where pulses are being lost.
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