The knock sensors (KS) produce an AC signal under all engine operating conditions. The powertrain control module (PCM) calculates the average voltage range of each KS signal. If the KS system is operating normally, the PCM should monitor the KS voltage varying above and below a calculated average voltage. This DTC will set if the PCM malfunctions in a manner that will not allow proper diagnosis of the KS system.
• | The engine run time is more than 10 seconds. |
• | The ignition voltage is more than 10 volts. |
• | A malfunction with the KS system within the PCM are faulty. |
• | All of the above conditions are present for 12 seconds. |
• | 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. |
• | 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 |
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Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module Connector End Views | |||
1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | |
2 |
Important: If you can hear the engine knock, repair the engine mechanical problem before proceeding with this diagnostic.
Does the DTC fail this ignition? | Go to Step 3 | Go to Intermittent Conditions |
3 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | Go to Step 4 | -- |
4 |
Does the scan tool indicate that this test ran and passed? | Go to Step 5 | Go to Step 2 |
5 | Select the Capture Info option and the Review Info option using the scan tool. Does the scan tool display any DTCs that you have not diagnosed? | Go to DTC List Diagnostic Trouble Code (DTC) List | System OK |