Knock Sensor 1 Circuit High Input (Bank 1 or Single Sensor)
Your knock sensor is sending a signal that's too high, like a smoke detector that won't stop screaming. The engine computer can't properly detect engine knock (pre-detonation) to adjust timing safely.
The ECU monitors the knock sensor's voltage signal, which detects vibrations from engine detonation. When voltage exceeds the normal operating range, the ECU cannot reliably distinguish real knock events from electrical noise. This triggers the fault code as a safety measure to prevent incorrect ignition timing adjustments.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Knock Sensor Voltage | 0.5–4.5 volts (typical AC signal centered) | Above 4.8 volts or stuck high signal |
| Signal Frequency Range | 5–15 kHz (detonation signature) | Signal out of range or constant DC voltage |
Code P0329 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, P0329 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.