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For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1999 🢒 Monte Carlo 🢒 Engine 🢒 Engine Controls - 3.8L 🢒 DTC P0325 Knock Sensor Module Performance

Object Number: 402827 Size: SF
OBD II Symbol Description Notice

Circuit Description

The PCM contains integrated Knock Sensor (KS) diagnostic circuitry. The PCM uses the circuitry to diagnose the KS sensors and related wiring. The PCM calculates an average voltage of each knock sensor's signals and takes instantaneous signal voltage readings. The PCM uses the instantaneous signal voltage readings to determine the state of the knock sensor circuitry. If the knock sensor system is operating normally, the PCM should monitor instantaneous KS signal voltage readings varying outside a voltage range above and below the calculated average voltage. If the PCM malfunctions in a manner which will not allow proper diagnosis of the KS circuit DTC 325 will set.

Conditions for Running the DTC
    • No TP sensor, VSS, CKP, MAF, or ECT DTCs are set.
    • Engine speed is between 1000 and 2500 rpm.
    • Engine has been running for greater than 30 seconds.
    • Throttle angle is greater than 10%.
    • Engine load is greater than 45%.
    • Engine coolant temperature is greater than 65°C (149°F).
    • Maximum spark retard is less than 15 degrees.
    • System voltage is greater than 9 volts.

Conditions for Setting the DTC

The PCM detects a malfunction in the integrated knock sensor diagnostic circuitry which will not allow proper diagnosis of the knock sensor circuits.

Action Taken When the DTC Sets

The PCM stores conditions which were present when the DTC set as Failure Records only. This information will not be stored as Freeze Frame Records.

Conditions for Clearing the MIL/DTC
    • The DTC becomes history when the conditions for setting the DTC are no longer present.
    • The history DTC clears after 40 malfunction free warm-up cycles.
    • The PCM receives a clear code command from the scan tool.

Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

  1. Ensures that the malfunction is present.

    2.

  2. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.

DTC P0325 - KS Module Circuit

Step

Action

Value(s)

Yes

No

1

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

Important:: If an engine knock can be heard repair the engine mechanical problem before proceeding with this diagnostic. Refer to Engine Noise Diagnosis in Engine Mechanical.

  1. Operate engine within conditions specified in diagnostic support. Refer to Conditions for Setting the DTC.
  2. Using a scan tool, monitor Specific DTC info for DTC P0325 until the DTC P0325 test runs.

Note test result; does scan tool indicate DTC P0325 failed this ign?

--

Go to Step 4

Go to Step 3

3
  1. Turn ON the ignition switch.
  2. Review and record scan tool Fail Records data for DTC P0325.
  3. Operate vehicle within Fail Records conditions.
  4. Using a scan tool, monitor Specific DTC info for DTC P0325 until the DTC P0325 test runs.

Does scan tool indicate DTC P0325 test failed this ign?

--

Go to Step 4

Go to Diagnostic Aids

4

Important:: The replacement PCM must be programmed.

Refer to Powertrain Control Module Replacement/Programming .

Replace the PCM.

Is action complete?

--

Go to Step 5

--

5
  1. Review and record Fail Records data
  2. Clear DTCs.
  3. Operate the vehicle within Fail Records conditions.
  4. Using a scan tool, monitor Specific DTC info for DTC P0325 until the DTC P0325 test runs.

Does the scan tool indicate DTC P0325 test failed this ign?

--

Go to Step 2

System OK