Circuit Description
The powertrain control module (PCM) contains integrated knock sensor (KS) diagnostic circuitry. The knock sensor (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 DTC will set if the KS signal is within the assigned voltage range or if the KS signal is not present.
Conditions for Running the DTC
| • | DTCs P0112, P0113, P0121, P0122, P0123, P0341, P0336, P0506, and P0507 are not set. |
| • | Engine speed is between 1,000-5,000 RPM. |
| • | The engine has been running for a minimum of 30 seconds. |
| • | Throttle angle is more than 15 percent . |
| • | Engine load is more than 40 percent . |
| • | Engine coolant temperature is more than 60°C (153°F). |
| • | Maximum spark retard is less than 15 degrees. |
| • | System voltage is more than 9.0 volts. |
Conditions for Setting the DTC
| • | The PCM detects a knock sensor signal voltage within the calculated average voltage range for at least 10 seconds. |
| • | Engine run time is more than 30 seconds. |
Action Taken When the DTC Sets
| • | The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed. |
| • | The PCM will store conditions which were present when the DTC set as Freeze Frame/Failure Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn OFF the malfunction indicator lamp (MIL) during the third consecutive trip in which the diagnostic has run and passed. |
| • | The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC can be cleared by using a scan tool. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
Ensures that the malfunction is present.
-
If either the 24X crank sensor and 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 | |
Using a scan tool, monitor the 24X crank sensor and the cam signal. Is the 24X signal and 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 - 2.5L (LB8) and 3.0L (LW9).
Does the DTC fail this ignition? | -- | Go to Step 4 | Go to Intermittent Conditions | |
4 |
Does the voltage measure near the specified value? | 0.0V | 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 | |
