P0325

DTC P0325 ION Sensing Module/ION Sensing Knock Intensity Circuit Fault




Circuit Description
The Power Control Module (PCM) checks the validity of the signals used in the ION Sensing module at the following engine operating conditions.
- The test is performed to evaluate the Knock Intensity (KI) signal pulse width if it is within a predetermined range. If the KI signal pules width is out of the predetermined range, the fail counter will be incremented. If the failure counter exceeds the calibration, then test is complete and a failure will be reported. If the sample counter threshold is reached before the failure threshold, then the test is complete and a pass will be reported. This test will detect an open/short in the KI line circuit, ION module faults and analog input faults in the PCM.

Conditions for setting the DTC
- Ignition voltage is between 10 volt and 16 volts.
- No Crank DTCs set.
- No EST DTCs.

Action Taken When the DTC Sets
- The PCM will illuminate the malfunction indicator lamp (MIL) the first time the fault is detected.
- The PCM calculates an air flow value based on Idle air Control valve position, throttle position, RPM and barometric pressure.
- The PCM will store condition which were present when the DTC was set as Freeze Frame and in the Failure Records data.

Conditions for Clearing the MIL/DTC
- The PCM will turn the MIL "OFF" on the third consecutive trip cycle during which the diagnostic has been run and the fault condition is no longer present.
- A history DTC P0325 will clear after 40 consecutive trip cycle during which the warm up cycles have occurred without a fault.
- DTC P0325 can be cleared using the Tech 2 "Clear Info" function or by disconnecting the PCM battery feed.

Diagnostic Aids
An intermittent may be caused by the following:
- Poor connections.
- Mis routed harness.
- Rubbed through wire insulation.
- Broken wire inside the insulation.

Check for the following conditions:
- Poor connection at PCM - Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
- Damaged harness - Inspect the wiring harness for damage.

If the harness appears to be OK, observe the Knock Present, Knock Sensor Noise Channel display on the Tech 2 while moving connectors and wiring harnesses related to the sensor. A change in the display will indicate the location of the fault.

If DTC P0325 cannot be duplicated, the information included in the Failure Records data can be useful in determined vehicle mileage since the DTC was last set.

If it is determined that the DTC occurs intermittently, performing the DTC P0325 Diagnostic Chart may isolate the cause of the fault.

Steps 1 - 5:

Steps 6 - 11:

Test Description