P0330 - Knock Sensor 2 Circuit
For a complete wiring diagram, refer to appropriate Wiring Diagram.
Theory of Operation
Spark knock is the spontaneous auto-ignition of the remaining fuel/air mixture in the engine combustion chamber that occurs after normal combustion has started. It can occur under extreme vehicle operating conditions such as high engine temperature, high MAP, low humidity and heavy loads to the engine. Spark knock is caused by excessive spark advance for the given engine operating conditions. Severe, continuous spark knock may be caused by carbon deposits, bad gasoline and/or low octane fuel. Avoiding light audible spark knock is important for customer satisfaction while preventing excessive spark knock is important to protect engine components. The output voltage from the Knock Sensor circuit represents the strength of the engine spark knock and is read by the engine controller. The knock system output voltage is not zero due to engine background noise, even when knock is not present. When the engine is operated under high load conditions where knock is possible, the Knock Sensor voltage is tested to decide if it exceeds the knock voltage threshold. Spark knock has occurred when the Knock Sensor voltage is at or above this knock threshold. When spark knock is detected a calibrated short term knock spark retard to be subtracted from the spark advance is calculated. The amount of retarded spark advance is based off a calibrated severity of the knock event. This retarded spark advance is used in the next ignition event to prevent further knock events. If spark knock continues, an additional amount of short term spark advance retard is added. When spark knock stops, short term knock retard is eliminated, the long term knock retard is reduced by a calibrated amount to recover some previously retarded spark advance. This decreases spark retard to improve engine performance.
- >>When Monitored:<< This monitor runs above 2000 RPM, under open throttle conditions. The Knock monitor does not run at idle or during decelerations. The high voltage test runs all the times the engine is running.
- >>Set Conditions:<< The Powertrain Control Module (PCM) detects that the Knock Sensor input voltage is: Above 4.0 Volts, less than or equal to 1.0 volt with engine RPM at or above 2200 or equal to 0.0 volts with engine RPM below 2200. Two Trip Fault. Three good trips to turn off the MIL.
| Possible Causes |
|---|
| (K242) KNOCK SENSOR NO. 2 SIGNAL CIRCUIT SHORTED TO VOLTAGE |
| (K242) KNOCK SENSOR NO. 2 SIGNAL CIRCUIT OPEN |
| (K924) KNOCK SENSOR NO. 2 RETURN CIRCUIT OPEN |
| (K242) KNOCK SENSOR NO. 2 SIGNAL CIRCUIT SHORTED TO THE (K924) KNOCK SENSOR NO. 2 RETURN CIRCUIT |
| (K242) KNOCK SENSOR NO. 2 SIGNAL CIRCUIT SHORTED TO GROUND |
| KNOCK SENSOR |
| POWERTRAIN CONTROL MODULE (PCM) |
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Refer to PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE .
Test Step 1 - ACTIVE DTC
- Start the engine.
- Allow the engine to reach normal operating temperature.
- With the scan tool, select View DTCs.
It may be necessary to drive the vehicle to meet the conditions to set this DTC, try to repeat the conditions in which the fault originally set by reviewing the Freeze Frame data.
Is the DTC Active or Pending at this time?
Yes
- Go to Test Step 2
No
- Perform the Checking for an Intermittent DTC diagnostic procedure. Refer to CHECKING FOR AN INTERMITTENT DTC .
Test Step 2 - (K242) KNOCK SENSOR NO. 2 SIGNAL CIRCUIT SHORTED TO VOLTAGE
- Turn the ignition off.
- Disconnect the Knock Sensor No. 2 harness connector.
- Disconnect the PCM C2 harness connector.
- Ignition on, engine not running.
- Measure the voltage on the (K242) Knock Sensor No. 2 Signal circuit in the Knock Sensor harness connector.
Is there any voltage present?
Yes
- Repair the short to voltage in the (K242) Knock Sensor No. 2 Signal circuit.
- Perform the Powertrain Verification Test. Refer to PCM VERIFICATION TEST (2009 - 2011) or PCM VERIFICATION TEST (2012 & UP) .
No
- Go to Test Step 3
Test Step 3 - (K242) KNOCK SENSOR NO. 2 SIGNAL CIRCUIT OPEN
- Turn the ignition off.
- Measure the resistance of the (K242) Knock Sensor No. 2 Signal circuit from the Knock Sensor harness connector to the PCM C2 harness connector.
Is the resistance below 5.0 Ohms?
Yes
- Go to Test Step 4
No
- Repair the open in the (K242) Knock Sensor No. 2 Signal circuit.
- Perform the Powertrain Verification Test. Refer to PCM VERIFICATION TEST (2009 - 2011) or PCM VERIFICATION TEST (2012 & UP) .
Test Step 4 - (K924) KNOCK SENSOR NO. 2 RETURN CIRCUIT OPEN
- Measure the resistance of the (K924) Knock Sensor No. 2 Return circuit from the Knock Sensor harness connector to the PCM C2 harness connector.
Is the resistance below 5.0 Ohms?
Yes
- Go to Test Step 5
No
- Repair the open in the (K924) Knock Sensor No. 2 Return circuit.
- Perform the Powertrain Verification Test. Refer to PCM VERIFICATION TEST (2009 - 2011) or PCM VERIFICATION TEST (2012 & UP) .
Test Step 5 - (K242) KNOCK SENSOR NO. 2 SIGNAL CIRCUIT SHORTED TO THE (K924) KNOCK SENSOR NO. 2 RETURN CIRCUIT
- Measure the resistance between the (K242) Knock Sensor No. 2 Signal circuit and the (K924) Knock Sensor No. 2 Return circuit in the Knock Sensor harness connector.
Is the resistance below 100 Ohms?
Yes
- Repair the short between the (K242) Knock Sensor No. 2 Signal circuit and the (K924) Knock Sensor No. 2 Return circuit.
- Perform the Powertrain Verification Test. Refer to PCM VERIFICATION TEST (2009 - 2011) or PCM VERIFICATION TEST (2012 & UP) .
No
- Go to Test Step 6
Test Step 6 - (K242) KNOCK SENSOR NO. 2 SIGNAL CIRCUIT SHORTED TO GROUND
- Measure the resistance between ground and the (K242) Knock Sensor No. 2 Signal circuit in the Knock Sensor harness connector.
Is the resistance below 100 Ohms?
Yes
- Repair the short to ground in the (K242) Knock Sensor No. 2 Signal circuit.
- Perform the Powertrain Verification Test. Refer to PCM VERIFICATION TEST (2009 - 2011) or PCM VERIFICATION TEST (2012 & UP) .
No
- Go to Test Step 7
Test Step 7 - KNOCK SENSOR 2
- Turn the ignition off.
- If no problems were found in the connectors, replace the Knock Sensor 2. Refer to REMOVAL AND INSTALLATION .
- Connect the PCM C2 harness connector.
- Turn the ignition on.
- With the scan tool, clear DTCs.
- Start the engine and allow it to reach normal operating temperature.
When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.
It may be necessary to test drive the vehicle within the DTC monitoring conditions in order for this DTC to reset.
- With the scan tool, select View DTCs.
Is the DTC Active at this time?
Yes
- Go to Test Step 8
No
- Test complete.
- Perform the Powertrain Verification Test. Refer to PCM VERIFICATION TEST (2009 - 2011) or PCM VERIFICATION TEST (2012 & UP) .
Test Step 8 - POWERTRAIN CONTROL MODULE (PCM)
- Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Knock Sensor 2 and the Powertrain Control Module (PCM).
- Look for any chafed, pierced, pinched or partially broken wires.
- Look for broken, bent, pushed out or corroded terminals.
- Perform any Technical Service Bulletins that may apply.
Were any problems found?
Yes
- Repair as necessary.
- Perform the Powertrain Verification Test. Refer to PCM VERIFICATION TEST (2009 - 2011) or PCM VERIFICATION TEST (2012 & UP) .
No
- Replace and program the Powertrain Control Module (PCM). Refer to REMOVAL AND INSTALLATION .
- Perform the Powertrain Verification Test. Refer to PCM VERIFICATION TEST (2009 - 2011) or PCM VERIFICATION TEST (2012 & UP) .