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 sensors are located below each cylinder head on 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 a signal circuit. The KS ground is supplied by the PCM through a low reference circuit. The PCM learns a minimum KS noise level at idle and uses calibrated values for the rest of the RPM range. The PCM should monitor a normal KS signal within the noise channel. This diagnostic trouble code (DTC) will set if the PCM detects the KS signal outside of the noise channel, or the KS signal is not present. DTC P0327 refers to the bank 1 KS and DTC P0332 refers to the bank 2 KS.
DTC Descriptors
This diagnostic procedure supports the following DTCs:
| • | DTC P0327 Knock Sensor (KS) Circuit Bank 1 |
| • | DTC P0332 Knock Sensor (KS) Circuit Bank 2 |
Conditions for Running the DTC
| • | DTC P0016, P0101, P0102, P0103, P0116, P0117, P0118, P0120, P0125, P0128, P0220, P0335, P0336, P0340, P0341, P0608, P1125, P1516, P2101, P2108, P2120, P2125, P2135, or P2138 is not set. |
| • | The engine speed is between 1,000-5,000 RPM. |
| • | The throttle position (TP) indicated 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 knock retard is less than 15 degrees. |
| • | The ignition 1 signal is more than 9 volts. |
| • | The engine run time is more than 30 seconds. |
| • | DTC P0327 and P0332 run continuously once the above conditions are met. |
Conditions for Setting the DTC
The KS signal is outside of the assigned noise channel or the KS signal is not present for more than 0.5 second.
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. |
| • | The KS must be clear of hoses, brackets, and engine electrical wiring. |
| • | 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 - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | ||||||||
2 |
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 - 3.5L (LX9).
Does the DTC fail this ignition? | -- | Go to Step 3 | Go to Diagnostic Aids | ||||||||
3 | Test for an intermittent and for a poor connection at the affected knock sensor (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 12 | Go to Step 4 | ||||||||
4 |
Is the resistance equal to the specified value for both measurements? | ∞ ohms | Go to Step 5 | Go to Step 10 | ||||||||
5 |
Important: Do not tap on plastic engine components. Does the DMM display a fluctuating frequency while tapping on the engine block? | -- | Go to Step 6 | Go to Step 10 | ||||||||
6 |
Is the voltage more than the specified value on any circuit? | 4.2 V | Go to Step 7 | Go to Step 8 | ||||||||
7 |
Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 9 | ||||||||
8 |
Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 9 | ||||||||
9 | 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 12 | Go to Step 11 | ||||||||
10 | Replace the affected KS. Refer to Knock Sensor Replacement . Did you complete the replacement? | -- | Go to Step 12 | -- | ||||||||
11 | Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 12 | -- | ||||||||
12 |
Does the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 13 | ||||||||
13 | 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 in Vehicle DTC Information | System OK | ||||||||
