P0325

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The knock sensor system detects for an engine detonation. The knock sensor produces an Idle Air Control (IAC) voltage signal. The amplitude and the frequency of the IAC voltage signal is dependent upon the knock level being detected. This signal then travels to the Knock Sensor (KS) module that is an internal part of the PCM. If knock is detected, the PCM will retard the spark timing based on the signal from the knock sensor.

CONDITIONS FOR SETTING THE DTC

^ Engine run time is greater than 20 seconds.

^ Engine Coolant Temperature (ECT) is greater than 56°C (131°F).

^ Engine speed is above 1600 RPM.

^ MAP is greater than 60 kPa.

^ Engine vacuum is less than 33 kPa.

^ The KS voltage and variation is not within normally expected ranges.

^ The above conditions are present for greater than 60 seconds.

ACTION TAKEN WHEN THE DTC SETS

^ The Malfunction Indicator Lamp (MIL) will illuminate.

^ The PCM will record operating conditions at the time the diagnostic fails. The Freeze Frame and Failure Records buffers will store this information.

^ A history DTC is stored.

^ The PCM will default to a more conservative spark timing.

CONDITIONS TO CLEARING THE MIL/DTC

^ The MIL will turn off after 3 consecutive ignition cycles in which the diagnostic runs without a fault.

^ A history DTC will clear after 40 consecutive warm up cycles without a fault.

^ A scan tool can clear the DTCs.

DIAGNOSTIC AIDS

^ Check and correct any abnormal engine noise before using the diagnostic table.

^ Thoroughly check any suspected circuitry for the following conditions:

- Backed out terminals.

- Improper mating.

- Broken locks.

- Improperly formed connectors.

- Damaged terminals.

- Poor terminal to wiring connections.

- Physical damage to the wiring harness.

TEST DESCRIPTION

Number(s) below refer to the step number(s) on the Diagnostic Table.

1. The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored on the scan tool for later reference.

2. If the conditions for the test as described above are met, a DTC P0325 will set and MIL will illuminate.

4. If the engine has an internal knock or audible noise that causes a knocking type noise on the engine block, the knock sensor may be responding to the noise.

6. Checking the internal resistance of the knock sensor or the wiring to the knock sensor is OK.

7. Any circuitry, that is suspected as causing the complaint, should be thoroughly checked for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wiring connections or physical damage to the wiring harness.

8. The replacement PCM must be programmed and the crankshaft position system variation procedure must be preformed. Refer to the latest Techline procedure for PCM reprogramming and also refer to Crankshaft Position (CKP) System Variation Learn Procedure for the Crankshaft Position System Variation Procedure.