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For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2007 🢒 Cobalt 🢒 Diagnostic Navigation 🢒 Vehicle Diagnostic Information 🢒 DTC P0326

Circuit 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 KS is located on the intake side of 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 2 isolated signal circuits. If the PCM is operating on large amounts of spark retard and is unable to eliminate the knock, DTC P0326 will set.

DTC Descriptor

This diagnostic supports the following DTC:

DTC P0326 Knock Sensor (KS) Performance

Conditions for Running the DTC
    • The engine speed is more than 1,800 RPM.
    • The manifold absolute pressure (MAP) is more than 55 kPa
    • DTC P0326 runs continuously when the above conditions are met.

Conditions for Setting the DTC
    • The KS signal indicates an engine knock is present.
    • The PCM commanded spark retard at a given engine load and speed is more than the calibrated value.
    • The above conditions exist for 8 seconds.

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.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Inspect for a loose or broken vehicle accessory and/or accessory bracket.
  2. If a condition is found, repair as necessary.

Did you find and correct the condition?

Go to Step 4

Go to Step 3

3
  1. Start the engine.
  2. Inspect for excessive engine mechanical noise. Refer to Symptoms - Engine Mechanical .
  3. If a condition is found, repair as necessary.

Did you find and correct the condition?

Go to Step 4

Go to Detonation/Spark Knock

4
  1. Clear the DTCs with a scan tool.
  2. Turn OFF the ignition for 30 seconds.
  3. Start the engine.
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.

Did the DTC fail this ignition?

Go to Step 2

Go to Step 5

5

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

Go to Diagnostic Trouble Code (DTC) List - Vehicle

System OK