DTC P0325, P0327, or P0328
Diagnostic Instructions
DTC Descriptors
DTC P0325: Knock Sensor Circuit
DTC P0327: Knock Sensor Circuit Low Voltage
DTC P0328: Knock Sensor Circuit High Voltage
Diagnostic Fault Information
Circuit
| Short to Ground
| Open/High Resistance
| Short to Voltage
| Signal Performance
|
Knock Sensor Signal
| P0327
| P0325
| P0328
| P0326
|
Knock Sensor Low Reference
| P0327
| P0325, P06B6
| P0328
| P0326
|
Circuit/System Description
The knock sensor enables the engine control module (ECM) to control the ignition timing for the best possible performance while protecting the engine from potentially damaging levels of detonation. The knock sensor produces an alternating current (AC) voltage signal that varies depending on the vibration level during engine operation. The ECM adjusts the spark timing based on the amplitude and the frequency of the knock sensor signal. The ECM receives the knock sensor signal through 2 isolated circuits. The ECM learns a minimum knock sensor noise level for all of the engine speed ranges. The ECM monitors for a normal knock sensor signal. The ECM monitors the internal knock sensor processor by verifying a 20 KHz signal generated on the signal circuit is detected on the sensor low reference circuit.
Conditions for Running the DTC
P0325
| • | Engine speed is between 600 and 8,500 RPM. |
| • | Engine is running at least 5 s. |
| • | The ECT is warmer than -40°C (-40°F). |
| • | The IAT is warmer than -40°C (-40°F). |
| • | The DTC runs continuously when the above conditions are met. |
P0327 and P0328
| • | Engine speed is less than 8,500 RPM. |
| • | The DTCs run continuously when the above condition is met. |
Conditions for Setting the DTC
P0325
The ECM detects that a knock sensor signal circuit is open.
P0327
The ECM detects that a knock sensor signal circuit is shorted to ground.
P0328
The ECM detects that a knock sensor signal circuit is shorted to voltage.
Action Taken When the DTC Sets
| • | DTCs P0325, P0327, and P0328 are Type B DTCs. |
| • | The ignition timing is retarded to reduce the potential of engine damaging spark knock. |
Conditions for Clearing the DTC
DTCs P0325, P0327, and P0328 are Type B DTCs.
Diagnostic Aids
| • | Inspect the knock sensor for physical damage. A sensor that is dropped or damaged may cause a DTC to set. |
| • | The sensor mounting surface must be free of burrs, casting flash, and foreign material. |
| • | The sensor must be clear of hoses, brackets, and engine electrical wiring. |
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Hybrid Modes of Operation Description
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Engine running, observe the DTC information with a scan tool. DTC P0325, P0327, or P0328 should not set.
- Move the related harnesses and connectors for the knock sensor circuits while observing the scan tool parameters listed below. The parameters should display NO.
| • | Cylinder 1 Knock Detected |
| • | Cylinder 2 Knock Detected |
| • | Cylinder 3 Knock Detected |
| • | Cylinder 4 Knock Detected |
| ⇒ | If the parameters change, repair the wiring or the harness connectors. |
- Observe the DTC information with a scan tool. DTC P0325, P0327, or P0328 should not set.
- Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.
Circuit/System Testing
- Verify the B68 knock sensor is properly tightened, refer to Fastener Tightening Specifications .
| ⇒ | If not the specified value, correct the condition as appropriate. |
- Vehicle OFF, disconnect the harness connector at the B68 knock sensor.
- Vehicle in Service Mode, measure for 1-4 V between each of the following circuits and ground on the K20 ECM side of the harness connector:
| • | The signal circuit, terminal 1 |
| • | The low reference circuit, terminal 2 |
| ⇒ | If less than the specified range, test the circuits for a short to ground or an open/high resistance. If the circuits test normal, replace the K20 ECM. |
| ⇒ | If greater than the specified range, test the circuits for a short to voltage. If the circuits test normal, replace the K20 ECM. |
- If all circuits test normal, replace the B68 knock sensor.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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