DTC P0326: Knock Sensor Module Circuit: Description
WARNING: This page is about a different car, the 2002 Oldsmobile Bravada, 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
The knock sensor (KS) produces an AC voltage at all engine speeds and loads. The Powertrain Control Module (PCM) then adjusts the spark timing based on the amplitude and frequency of the KS signal. The PCM uses the KS signal to calculate the average voltage. Then the PCM assigns a voltage value. The PCM checks the knock sensor and related wiring by comparing the actual knock signal to the assigned voltage range. A normal KS signal should stay outside the assigned voltage range. This Diagnostic Trouble Code (DTC) will set if the PCM malfunctions in a manner that will not allow proper diagnosis of the KS system. The KS system uses 2 knock sensors. Both sensors are connected directly to the PCM using the following circuits:
- The KS 1 signal circuit.
- The KS 1 low reference circuit.
- The KS 2 signal circuit.
- The KS 2 low reference circuit.