DTC Descriptors
DTC P0325: Knock Sensor (KS) Module PerformanceDTC P0327: Knock Sensor (KS) Circuit Bank 1
DTC P0332: Knock Sensor (KS) Circuit Bank 2
Diagnostic Fault Information
Important: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
|---|---|---|---|---|---|
Knock Sensor Signal | P0327 | P0325, P0327 | P0325, P0327 | P0325, P0327 | P0326 |
Low Reference | P0327 | P0327 | P0327 | P0325, P0327 | P0326 |
Typical Scan Tool Data
Circuit | Normal Range | Short to Ground | Open | Short to Voltage |
|---|---|---|---|---|
Knock Sensor/Spark | 11-20 | 0-25 | 0-25 | 0-25 |
Circuit/System Description
The Knock Sensor (KS) System enables the powertrain control module (PCM) to control the ignition timing for the best possible performance while protecting the engine from potentially damaging levels of detonation. The sensors are located below each cylinder head on the engine block. The KS produces an AC voltage signal that varies depending on the vibration level during engine operation. The PCM adjusts the spark timing based on the amplitude and the frequency of the KS signal. The PCM receives the KS signal through a signal circuit. The KS ground is supplied by the PCM through a low reference circuit. The PCM learns a minimum KS noise level at idle and uses calibrated values for the rest of the RPM range. The PCM should monitor a normal KS signal within the noise channel. If the PCM malfunctions in a manner that will not allow proper diagnosis of the KS system, DTC P0325 sets. If the PCM detects the KS signal outside of the noise channel, or the KS signal is not present. DTC P0327 refers to the bank 1 KS and DTC P0332 refers to the bank 2 KS.
Conditions for Running the DTC
| • | DTC P0016, P0101, P0102, P0103, P0116, P0117, P0118, P0120, P0125, P0128, P0220, P0335, P0336, P0340, P0341, P0608, P1125, P1516, P2101, P2108, P2120, P2125, P2135, or P2138 is not set. |
| • | The engine speed is between 1,000-5,000 RPM. |
| • | The throttle position (TP) indicated angle is more than 10 percent. |
| • | The engine load is more than 40 percent. |
| • | The engine coolant temperature (ECT) is more than 60°C (140°F). |
| • | The knock retard is less than 15 degrees. |
| • | The ignition 1 signal is more than 9 volts. |
| • | The engine run time is more than 30 seconds. |
| • | DTC P0325, P0327 and P0332 run continuously once the above conditions are met. |
Conditions for Setting the DTC
P0325
The PCM detects a malfunction in the KS diagnostic circuitry that will not allow proper diagnosis of the KS system.
P0327 or P0332
The KS signal is outside of the assigned noise channel or the KS signal is not present for more than 0.5 second.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Diagnostic Aids
| • | Inspect the KS for physical damage. A KS that is dropped or damaged may cause a DTC to set. |
| • | Inspect the KS for proper installation. A KS that is loose or over torqued may cause a DTC to set. The KS should be free of thread sealant. The KS mounting surface should be free of burrs, casting flash, and foreign material. |
| • | The KS must be clear of hoses, brackets, and engine electrical wiring. |
Reference Information
Schematic Reference
Connector End View Reference
Electrical Information Reference
Circuit/System Testing
Important:
• Always perform the
Diagnostic System Check - Vehicle
prior to using this diagnostic procedure. • If an engine mechanical noise can be heard, repair the condition before proceeding with this diagnostic. Refer to
Symptoms - Engine Mechanical
.
- Test for an intermittent and for a poor connection at the affected knock sensor (KS).
- With the ignition OFF, disconnect the affected knock sensor.
- With the ignition OFF, Measure the resistance for infinite ohms from the sensor signal terminal on the knock sensor to a good ground, and the low reference terminal on the knock sensor to a good ground with a DMM.
- Connect the DMM between the terminals of the affected KS. Set the DMM to the 400 Hz scale, let stabilize at 0 Hz. Tap on engine block with a non-metallic object near the affected KS while observing the signal indicated on the DMM.
- Turn the ignition ON, engine OFF. Set the DMM to the DC voltage scale. Measure for 4.2 volts from the KS signal circuit to a good ground, and the KS low reference circuit to a good ground with the DMM.
- Test for intermittent or poor connections at the PCM.
- If all circuits test normal then replace the PCM.
| ⇒ | If resistance does not measure infinite ohms at both terminals than replace the affected KS. |
Important: Do not tap on plastic engine components.
| ⇒ | If the DMM does not display a fluctuating frequency while tapping on the engine block then replace the affected KS. |
| ⇒ | If over 4.2 volts with the ignition OFF disconnect the PCM and test the KS signal circuit or the KS low reference circuit for a short to voltage. |
| ⇒ | If under 4.2 volts with the ignition OFF disconnect the PCM test the KS signal circuit or the KS low reference circuit for an open, short to ground, or high resistance. |
Repair Instructions
Important: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for engine control module (ECM) replacement, setup, and programming |
