The powertrain control module (PCM) contains integrated knock sensor (KS) diagnostic circuitry. The KS produces an AC voltage at all engine speeds and loads. The PCM then adjusts spark timing based on the amplitude and frequency of the KS signal. The PCM uses the KS signal to calculate the average voltage. Then, the PCM assigns a voltage value. The PCM checks the knock sensor and related wiring by comparing the actual knock signal to the assigned voltage range. A normal KS signal should stay outside the assigned voltage range. This diagnostic trouble code (DTC) will set if the KS signal is within the assigned voltage range or if the KS signal is not present.
• | DTCs P0112, P0113, P0121, P0122, P0123, P0336, P0341, P0506, or P0507 are not set. |
• | The engine speed is between 1000-5000 RPM. |
• | The engine has been running for a minimum of 30 seconds. |
• | The throttle angle is more than 15 percent . |
• | The engine load is more than 40 percent . |
• | The engine coolant temperature is more than 60°C (153°F). |
• | The maximum spark retard is less than 15 degrees. |
• | The system voltage is more than 9 volts. |
• | The PCM detects a knock sensor signal voltage within the calculated average voltage range for at least 10 seconds. |
• | The engine run time is more than 30 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. |
The numbers below refer to the step numbers on the diagnostic table.
This step ensures that the malfunction is present.
If either the 24X crank sensor or the cam signal are not present, the KS signal will stop updating and may set DTC P0327. The 12-volt reference supply and the low reference need to be diagnosed using the DTC P0336.
Step | Action | Values | Yes | No |
---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||
1 | Did you perform the Diagnostic System Check-Engine Controls? | -- | Go to Step 2 | |
2 | Using a scan tool, monitor the 24X crank sensor and the cam signal. Are the 24X signal and the cam signal present? | -- | Go to Step 3 | Go to DTC P0336 |
Important: If a mechanical engine knock can be heard, repair the engine mechanical problem before proceeding with this diagnostic. Refer to Symptoms - Engine Mechanical in Engine Mechanical.
Does the DTC fail this ignition? | -- | Go to Step 4 | Go to Intermittent Conditions | |
4 |
Does the voltage measure near the specified value? | 0 V | Go to Step 6 | Go to Step 5 |
5 | Repair the short to voltage in the KS signal circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 10 | -- |
6 |
Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 7 |
7 |
Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 8 |
8 |
Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 9 |
9 | Replace the knock sensor. Refer to Knock Sensor Replacement . Did you complete the replacement? | -- | Go to Step 10 | -- |
10 |
Does the DTC run and pass? | -- | Go to Step 11 | Go to Step 2 |
11 | With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK |