Circuit Description
The knock sensor (KS) is a piezoelectric device that produces an AC voltage of different amplitude and frequency depending on the level of engine mechanical vibration. The KS system monitors the knock sensor in order to determine if detonation or spark knock is present. If the KS system determines that excessive knock is present, the engine control module (ECM) retards the spark timing based on the signal from the KS system. The KS produces an AC signal when specific frequencies are detected. The ECM then retards the timing until knock is controlled.
In order to differentiate between normal engine noise and spark knock, the ECM samples the KS signal. The ECM samples the KS signal for a certain length of time under different engine speeds and loads during non-cylinder knock events. This sampling is used to determine a range of acceptable normal engine noise. If the ECM detects too much normal engine noise from a KS, a KS DTC sets.
DTC Descriptors
This diagnostic procedure supports the following DTCs:
| • | DTC P0328 Knock Sensor (KS) Circuit High Voltage Bank 1 |
| • | DTC P0333 Knock Sensor (KS) Circuit High Voltage Bank 2 |
Conditions for Running the DTC
| • | Before the ECM can report DTC P0328 or P0333 failed, DTCs P0324, P0335, P0336, and P0338 must run and pass. |
| • | DTCs P0341, P0342, P0343, P0346, P0347, P0348, P0366, P0367, P0368, P0391, P0392, and P0393 are not set. |
| • | The engine speed is more than 2,000 RPM. |
| • | The change in engine speed per second is less than 2,300 RPM. |
| • | The change in engine load per second is less than 50-100 kPa |
| • | The engine coolant temperature (ECT) sensor is more than 60°C (140°F). |
| • | DTCs P0328 and P0333 run continuously once the above conditions are met for approximately 20 seconds. |
Conditions for Setting the DTC
The ECM detects a KS signal voltage that is more than references KS signal voltage, which lasts for 100 pulse frequency.
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 4 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
| • | Use the J 35616-A/BT-8637 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector. |
| • | The lower connector of the ECM is connector C1 and the upper connector of the ECM is connector C2. Refer to Front of Vehicle/Engine Compartment Component Views. |
| • | The KS must be torqued correctly. Refer to Fastener Tightening Specifications. |
| • | The mounting between the sensor and engine must be free of burrs, casting flash, and foreign material. |
| • | The KS is clear from hoses, brackets, and engine wiring. |
| • | For an intermittent condition, refer to Intermittent Conditions. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step verifies a condition is present.
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This step is testing for electromagnetic interference (EMI). If the KS circuits are routed close to high load circuits or components, this DTC may set.
-
This step is testing for a poor connection at the component and for an intermittent condition with the wiring.
-
This step is testing if the KS is installed correctly. A KS that is not fully seated, may cause this DTC to set.
Step | Action | Values | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Component Connector End Views | ||||||||||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||||||
|
Note: If you can hear an engine knock, repair the engine mechanical condition before proceeding with this diagnostic. Refer to Symptoms - Engine Mechanical.
Does the DTC fail this ignition? | -- | Go to Step 4 | Go to Step 3 | |||||||||
3 |
Did the DTC fail this ignition? | -- | Go to Step 4 | Go to Diagnostic Aids | ||||||||
Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 5 | |||||||||
Does the KS parameter change abruptly while moving the related harnesses? | -- | Go to Step 11 | Go to Step 6 | |||||||||
Did you find and correct the condition? | 23 N·m (17 lb ft) | Go to Step 15 | Go to Step 7 | |||||||||
7 |
Did the same KS DTC fail? | -- | Go to Step 9 | Go to Step 8 | ||||||||
8 | Did the opposite bank KS DTC fail? | -- | Go to Step 13 | Go to Step 12 | ||||||||
9 | Test for an intermittent and for a poor connection at the KS. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 10 | ||||||||
10 | Test for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 14 | ||||||||
11 | Repair the appropriate KS circuit. Refer to Wiring Repairs. Did you complete the repair? | -- | Go to Step 15 | -- | ||||||||
12 | Repair the poor connection at the KS. Refer to Wiring Repairs and Connector Repairs. Did you complete the repair? | -- | Go to Step 15 | -- | ||||||||
13 | Replace the KS. Refer to the appropriate procedure: Did you complete the replacement? | -- | Go to Step 15 | -- | ||||||||
14 | Replace the ECM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 15 | -- | ||||||||
15 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 16 | ||||||||
16 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |||||||||
