Diagnostic Instructions
DTC Descriptors
DTC P0325: Knock Sensor (KS) Module Performance - Non European Emissions
DTC P0325: Knock Sensor (KS) Circuit - European Emissions
Circuit/System Description
The knock sensor (KS) 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 KS produces an 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 KS signal. The ECM receives the KS signal through a signal circuit . The ECM supples a ground circuit to the KS through
a low reference circuit . The ECM also supplies a shielded ground circuit to the KS. The ECM learns a KS noise level at idle and uses calibrated values for the rest of the engine speed range. The ECM should monitor a normal KS signal within the noise channel.
Conditions for Running the DTC
• | DTCs P0106, P0107 and P0108 are not set. |
• | The engine speed is greater than 1,600 RPM. |
• | The engine coolant temperature (ECT) is more than 50°C (122°F) for Euro III Emissions or 66°C (151°F) for Euro IV Emissions. |
• | The manifold absolute pressure (MAP) is between 10-50 kPa which depends on engine speed. |
• | DTC P0325 runs continuously once the above conditions are met. |
Conditions for Setting the DTC
P0325 - Non European Emissions
The control module has detected an internal circuitry fault.
P0325 - European Emissions
The ECM detects an incorrect KS signal for greater than 4 seconds.
Action Taken When the DTC Sets
DTC P0325 is a Type C DTC.
Conditions for Clearing the DTC
DTC P0325 is a Type C DTC.
Reference Information
Schematic Reference
Engine Controls Schematics
Description and Operation
Knock Sensor (KS) System 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
- Ignition ON, observe the DTC information with a scan tool. DTC P0325 should not set.
⇒ | If DTC P0325 failed this ignition, for a Non European Emissions system, test or replace the ECM. |
- 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 - European Emissions Only
Important: If the knock sensor lead is damaged in any way, replace the knock sensor.
- Ignition OFF, disconnect the harness connector at the KS sensor.
- Ignition ON, connect a test lamp between the signal circuit terminal 1 and ground. The test lamp should not illuminate.
⇒ | If the test lamp illuminates, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM. |
- Connect a test lamp between the signal circuit terminal 1 and 12 volts. The test lamp should not illuminate.
⇒ | If the test lamp illuminates, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM. |
- Ignition OFF, connect a DMM between the signal circuit terminal 1 and the low reference circuit terminal 2.
- Test for 90-110K ohms of resistance between the signal circuit terminal 1 and the low reference circuit terminal 2.
⇒ | If not within the specified range, test the circuits for an open/high resistance. If the circuits test normal, replace the ECM. |
- If all circuits test normal, test or replace the KS sensor.
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
Control Module References
for engine control module replacement, setup, and programming