Timing Reference High Resolution Signal A Intermittent/Erratic Pulses
Your engine's timing sensor is sending unstable or flickering signals, like a light switch that keeps cutting on and off instead of staying steady. The ECU can't reliably determine when to fire the spark plugs, causing performance issues.
The ECU monitors the camshaft or crankshaft position sensor signal for consistent, clean pulses at expected intervals. It detects timing reference gaps and validates pulse width and frequency against learned patterns. If pulses become intermittent, drop out randomly, or show erratic timing, the ECU logs this fault.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Signal Pulse Frequency | Consistent tooth-to-tooth timing within 2-5% variance | Variance exceeds 10% or signal dropout detected |
| Signal Voltage Stability | 0.2V to 4.8V (digital square wave) | Intermittent drops, noise spikes, or erratic transitions |
Code P0374 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.
Once the fault is repaired, P0374 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.