P0325 Knock Sensor 1 Circuit

When monitored code P0325 - engine speed above 2000 rpm, battery voltage between 7.5 volts and 15.8 volts, barometric pressure is above 75.2 kpa. Set conditions, the Powertrain Control Module (PCM) detects that the knock sensor input voltage is either, above 4.8 volts - less than 0.2 volts when engine speed is above 2000 rpm. Default actions, MIL light illuminate.

Possible causes:

• Knock sensor 1 signal circuit shorted to voltage.
• Knock sensor 1 signal circuit open.
• Knock sensor 1 return circuit open.
• Knock sensor 1 signal circuit shorted to the knock sensor return circuit.
• Knock sensor 1 signal circuit shorted to ground.
• Knock sensor.
• Powertrain Control Module (PCM).

Diagnose P0325 Knock Sensor 1 Circuit

Step 1. Check for an active DTC

Start the engine. Test drive or operate the vehicle in accordance with the when monitored and set conditions. With the scan tool, read DTC.

Is the DTC active or pending?

Yes, go to step 2.

No, perform the the PCM intermittent condition.

Step 2. Check the knock sensor 1 signal circuit for a short to voltage

Turn the ignition off, disconnect the knock sensor harness connector. Turn the ignition on, measure the voltage on the knock sensor 1 signal circuit in the knock sensor harness connector.

Is the voltage abobe 5.2 volts?

Yes, repair the knock sensor 1 signal circuit for a short to voltage.

No, go to step 3.

Step 3. Check the knock sensor 1 signal circuit for an open/high resistance

Turn the ignition off, disconnect the PCM harness connector. Measure the resistance of the knock sensor 1 signal circuit from the knock sensor harness connector to the PCM harness connector.

Is the resistance below 3.0 Ohms?

Yes, go to step 4.

No, repair the knock sensor 1 signal circuit for an open or high resistance.

(Sorry!!! Step 4-8, refer to code P0330)

Step 4. Check the knock sensor 1 return circuit for an open/high resistance

Step 5. Check for the knock sensor 1 signal circuit shorted to the knock sensor 1 return circuit

Step 6. Check the knock sensor 1 signal circuit for a short to ground

Step 7. Knock sensor

Step 8. Check related PCM and component connections

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