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 PCM monitors 2 sensors. Each KS produces an AC signal that varies at all engine speeds and loads. The PCM makes adjustments to the spark timing based on the amplitude and frequency of the KS signal. The PCM receives the KS signal through a signal circuit. The KS ground is supplied by the engine block through the sensor housing. The PCM uses the KS signal to calculate an average voltage range. The PCM inspects the KS and the related wiring by comparing the actual knock signal to the assigned voltage range. If the KS system is operating correctly, the PCM should monitor the KS voltage varying above and below the predetermined average voltage. If the KS signal is within the assigned voltage range, or if the KS signal is not present, a DTC will set. DTC P0327 refers to the bank 1 KS and DTC P0332 refers to the bank 2 KS.
Conditions for Running the DTC
| • | DTCs P0068, P0101, P0102, P0103, P0116, P0117, P0118, P0120, P0125, P0128, P0220, P0336, P0341, P0502, P0503, P1114, P1115, P1125, P1516, P1518, P2101, P2107, P2108, P2119, P2120, P2125, P2135, P2138 are not set. |
| • | The engine speed is between 1,000-2,500 RPM. |
| • | The throttle angle is more than 10 percent. |
| • | The engine load is more than 40 percent. |
| • | The engine coolant temperature (ECT) is more than 60°C (140°F). |
| • | The maximum spark retard is less than 15 degrees. |
| • | The system voltage is more than 11 volts. |
| • | The engine run time is more than 30 seconds. |
Conditions for Setting the DTC
The PCM detects a KS signal voltage within the predetermined average voltage range for at least 10 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. |
Diagnostic Aids
| • | Inspect the KS for physical damage. A KS that is dropped or damaged may cause a DTC to set. |
| • | Inspect the KS for proper installation. A KS that is loose or over torqued may cause a DTC to set. The KS should be free of thread sealant. The KS mounting surface should be free of burrs, casting flash, and foreign material. |
| • | For an intermittent condition, refer to Intermittent Conditions . |
Step | Action | Values | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
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 |
Does the scan tool display any other DTCs? | -- | Go to Step 3 | |||||||||
3 |
Important: If an engine mechanical noise can be heard, repair the condition before proceeding with this diagnostic. Refer to Symptoms - Engine Mechanical in Engine Mechanical-3.8L.
Does the DTC fail this ignition? | -- | Go to Step 4 | Go to Diagnostic Aids | ||||||||
4 |
Is the resistance of the KS within the specified range? | 93-107K ohms | Go to Step 5 | Go to Step 11 | ||||||||
5 |
Important: Do not tap on plastic engine components. Is a signal indicated on the DMM while tapping on the engine block? | -- | Go to Step 6 | Go to Step 11 | ||||||||
6 |
Is the voltage more than the specified value? | 0.5 V | Go to Step 7 | Go to Step 8 | ||||||||
7 |
Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 12 | ||||||||
8 |
Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 9 | ||||||||
9 | Test for an intermittent and for a poor connection at the affected KS. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 10 | ||||||||
10 | Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 12 | ||||||||
11 | Replace the affected KS. Refer to Knock Sensor 1 Replacement or Knock Sensor 2 Replacement . Did you complete the replacement? | -- | Go to Step 13 | -- | ||||||||
12 | Replace the PCM. Refer to Powertrain Control Module Replacement . Did you complete the replacement? | -- | Go to Step 13 | -- | ||||||||
13 |
Does the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 14 | ||||||||
14 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |||||||||
