P0325

P0325 - Knock Sensor 1 Circuit

For wiring diagrams, refer to.

• When Monitored: With the engine running, battery voltage greater than 10 volts, and no system voltage DTCs present. The low voltage diagnostic runs continuously. The high voltage diagnostic runs during engine closed throttle conditions.

• Set Condition: The PCM detects that the knock sensor input voltage is: (A) more than 4.0 volts, (B) less than or equal to 1.0 volt with engine RPM at or more than 2200, or (C) equal to 0.0 volts with engine RPM less than 2200.

• Always perform the pre-diagnostic troubleshooting procedure before proceeding. Refer to => Non-DTC Based Diagnostics. Pre-Diagnostic Troubleshooting Procedure

Test Step 1 - DTC is Active

• Start the engine and allow it to reach normal operating temperature.

When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.

• It may be necessary to test drive the vehicle within the DTC monitoring conditions in order for this DTC to reset.

• With the scan tool, select view DTCs.

Is the status active for this DTC?

Yes

• Go to Test Step 2 => [ Test
Step 2 - KS 1 Signal Circuit Shorted to Voltage ]

No

• Refer to the checking for an intermittent DTC diagnostic procedure. Refer to => Non-DTC Based Diagnostics. Checking for an Intermittent DTC

Test Step 2 - KS 1 Signal Circuit Shorted to Voltage

• Turn the ignition OFF.

• Disconnect the knock sensor 1 connector.

• Disconnect the PCM connector.

• Turn the ignition ON.

• Measure the voltage of the knock sensor 1 signal circuit in the knock sensor 1 harness connector.

Is there any voltage present?

Yes

• Repair the knock sensor 1 signal circuit for a short to voltage.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

No

• Go to Test Step 3 => [ Test
Step 3 - KS 1 Signal Circuit Shorted to Ground ]

Test Step 3 - KS 1 Signal Circuit Shorted to Ground

• Turn the ignition OFF.

• Measure the resistance between ground and the knock sensor 1 signal circuit in the knock sensor 1 harness connector.

Is the resistance more than 100 ohms?

Yes

• Go to Test Step 4 => [ Test
Step 4 - KS 1 Signal Circuit Shorted to the KS 1 Return Circuit ]

No

• Repair the knock sensor 1 signal circuit for a short to ground.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

Test Step 4 - KS 1 Signal Circuit Shorted to the KS 1 Return Circuit

• Measure the resistance between the knock sensor 1 signal circuit and the knock sensor 1 return circuit in the knock sensor 1 harness connector.

Is the resistance more than 100 ohms?

Yes

• Go to Test Step 5 => [ Test
Step 5 - KS 1 Signal Circuit Open or High Resistance ]

No

• Repair the knock sensor 1 signal circuit for a short to the knock sensor 1 return circuit.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

Test Step 5 - KS 1 Signal Circuit Open or High Resistance

Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals, resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.

• Measure the resistance of the knock sensor 1 return circuit between the knock sensor 1 harness connector and the appropriate terminal of special tool #8815.

Is the resistance less than 5.0 ohms?

Yes

• Go to Test Step 7 => [ Test
Step 7 - Knock Sensor 1 ]

No

• Repair the knock sensor 1 return for an open circuit or high resistance.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

Test Step 7 - Knock Sensor 1

• Turn the ignition OFF.

• Replace the knock sensor 1.

• Connect the PCM connector.

• Turn the ignition ON.

• With the scan tool, clear DTCs.

• Start the engine and allow it to reach normal operating temperature.

When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.

• It may be necessary to test drive the vehicle within the DTC monitoring conditions in order for this DTC to reset.

• With the scan tool, select view DTCs.

Is the status active for this DTC?

Yes

• Go to Test Step 8 => [ Test
Step 8 - PCM ]

No

• Test complete.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

Test Step 8 - PCM

• Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the knock sensor 1 and the PCM.

• Look for any chafed, pierced, pinched, or partially broken wires.

• Look for broken, bent, pushed out or corroded terminals.

• Refer to any technical service bulletins that may apply.

Were any problems found?

Yes

• Repair as necessary.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test

No

• Replace and program the PCM.

• Perform the PCM Verification Test. Refer to => Non-DTC
Based Diagnostics. PCM Verification Test