1.15.13.2 Reference signal check

P0327 (KS1min), P1327 (KS2min), P1329 (KS3min), P033C (KS4min), P0328 (KS1max), P1328 (KS2max), P1330 (KS3max), P033D (KS4max) 

A reference signal (Uref) is calculated based on the knock sensor signal. This reference value represents the basic noise of the current sensor being analyzed. When the monitoring conditions are fulfilled, Uref is compared with the lower and upper calibrated engine-speed-dependent thresholds and detected faults are counted.

If the fault counter exceeds a calibrated threshold and Uref lies below the lower calibrated threshold, a malfunction is detected and a KSxmin fault will be set.

If the fault counter exceeds a calibrated threshold and Uref exceeds the upper calibrated threshold, a malfunction is detected and a KSxmax fault will be set.

The fault path is cleared when the current reference level for a calibrated number of successive checks again lies within the range bounded by the upper and lower calibrated reference thresholds (for a calibrated period of time).