Circuit Description

Knock sensor is used to detect engine detonation. Knock sensor produces and sends an AC voltage signal to PCM to identify that engine knock is being detected. PCM will retard timing based on this signal. PCM may reject a signal that appears to be a false signal. If PCM still detects a high noise level, DTC P0327 will be set.

Conditions required to set DTC are:

A/D Test

• Engine speed is 2500 RPM or greater.
• A/D voltage is .0781 volts or less.
• Engine coolant temperature is more than 140°F (60°C).
• Engine vacuum is less than 35 kPa.
• Abnormal noise level sensed for 8 seconds of 10-second period.

Gain Test

• Engine speed is greater than 2500 RPM.
• Gain is 23.875 decibels or more.