P0327 — Knock Sensor 1 Circuit Low (Bank 1 or Single Sensor)

What it means

The voltage arriving from knock sensor 1 on bank 1 stays below the calibrated threshold, so the module sees the circuit as shorted to ground or the piezo element as dead. Because the module can no longer confirm the absence of detonation, it applies a permanent safety ignition retard. The driver notices sluggish acceleration, weaker pull uphill and increased fuel consumption, usually without any change in idle quality.

Likely causes (most common first)

1. Knock sensor with a degraded piezo element producing almost no output
2. Short to ground in the signal wire or damaged cable screen
3. Water filled or corroded connector, spread terminal contacts
4. Loose sensor mounting bolt so vibration does not reach the element
5. Open circuit in the sensor return or a bad sensor ground point
6. Defective knock input inside the ECM

Can you drive with it?

Safe to drive with reduced power; use good quality fuel and repair without long delay.