P0325

DTC P0325 Knock Sensor Module Circuit




Circuit Description
The VCM contains a removable Knock Sensor Module which receives the Knock sensor input. The knock Sensor signal input is filtered by this module before it is input to the VCM. The VCM continuously monitors this module for spark knock during engine operation. If the VCM detects knock for longer than a calibrated time, this DTC will be set.

Conditions for Running the DTC
- DTC P0327 is not active
- The engine run time is greater than 120 seconds.
- System voltage is between 10 - 17.1 volts.

Conditions for Setting the DTC
The VCM detects engine knock for more than 5 seconds.

Action Taken When DTC Sets
- The VCM will not illuminate the MIL
- The VCM stores the conditions that were present when the DTC set as a Fail Records data only. This information is not stored as Freeze Frame Data.
- The VCM uses a calculated spark retard value in order to minimize the knock during the conditions when the knock is most likely to occur. This calculated value is based on the engine speed and load.

Conditions for Clearing the MIL/DTC
- The VCM turns OFF the MIL after 3 consecutive drive trips when the test has Run and Passed.
- A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (coolant temperature has risen 22 °C (40 °F) from the startup coolant temperature and the engine coolant temperature is more than 70 °C (158 °F) during the same ignition cycle).
- Use the scan tool Clear Information function.

Diagnostic Aids
Check for the following conditions:
- A poor connection at the VCM. Inspect the knock sensor and the VCM connectors for the following items:
- Backed out terminals
- Broken locks
- Improperly formed or damaged terminals
- A damaged or improperly installed knack Sensor Module. Check the following items:
- Bent pins
- Deformed terminals
- Knock Sensor Module is not completely seated.
- A misrouted harness. Inspect the knock sensor harness in order to ensure that it is not routed too close to high voltage wires such as spark plug leads.
- Improper knock Sensor torque specification. Refer to Fastener Note in Service Precautions. Torque the Knock Sensor to 19 N.m (14 lbs ft).

Review the Fail Records vehicle mileage since the diagnostic test last failed in order to help determine how often the conditions that caused the DTC to set occur. This may assist in diagnosing the condition.

An intermittent may be caused by any of the following conditions:
- A poor connection
- Rubbed through wire insulation
- A broken wire inside the insulation

Thoroughly check any circuitry that is suspected of causing the intermittent complaint. Refer to Intermittents and Poor Connections Diagnosis.

If a repair is necessary, then refer to Wiring Repairs or Connector Repairs.

Steps 1 - 3:

Steps 4 - 7:

Steps 8 - 10:

Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. This step ensures that the condition is present.
5. This step checks for an improperly installed knock sensor module.