Circuit Description
The powertrain control module (PCM) contains integrated knock sensor (KS) diagnostic circuitry. An input signal from the KS is used to detect engine detonation, allowing the PCM to retard ignition control (IC) spark timing based on the amplitude and frequency of the KS signal being received. The KS produces an AC signal under all engine operating conditions. During engine operation, the PCM calculates the average voltage of the KS signal. If the knock sensor system is operating normally, the PCM will see KS signal voltage vary above and below the calculated voltage average. If the PCM detects KS input signal equal to the KS average voltage over 95 percent of a calibrated time, DTC P0327 will set.
Conditions for Running the DTC
| • | No TP, CMP, CKP, ECT Sensor, or VSS DTCs are set. |
| • | Engine speed is between 1000 and 5000 RPM. |
| • | The engine has been running for a minimum of 30 seconds. |
| • | Throttle angle is more than 15 percent. |
| • | Engine load is more than 45 percent. |
| • | Engine coolant temperature is more than 60°C (140°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 KS signal voltage within the calculated average voltage range for at least 10 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. |
Diagnostic Aids
Inspect for the following conditions:
Many situations may lead to an intermittent condition. Perform each inspection or test as directed.
Important: : Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.
| • | Loose terminal connection |
| - | Use a corresponding mating terminal to test for proper tension. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| - | Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| • | Damaged harness--Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
| • | Inspect the powertrain control module (PCM) and the engine grounds for clean and secure connections. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
If the condition is determined to be intermittent, reviewing the Snapshot or Freeze Frame/Failure Records may be useful in determining when the DTC or condition was identified.
Test Description
The numbers below refer to the numbers on the diagnostic table:
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This step ensures that the malfunction is present.
-
If both the 24X crank sensor and the Cam signal are not present the KS signal will stop updating and may set DTC P0327. The ignition positive voltage supply and the ground circuits need to be diagnosed using the DTC P0336.
-
If sent here from Symptoms, proceed with the diagnostic table.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On Board Diagnostic (OBD) System Check? | -- | ||
|
Important : If a mechanical engine knock can be heard, repair the engine mechanical
problem before proceeding with this diagnostic. Refer to
Engine Noise Diagnosis
in
Engine Mechanical.
Does scan tool indicate DTC P0327 failed this ignition? | -- | |||
Using scan tool, monitor 24X crank sensor and the cam signal. Are both the 24X signal and/or Cam Signal present? | -- | Go to DTC P0336 Crankshaft Position (CKP) Sensor Performance | ||
Does the scan tool indicate DTC P0327 failed this ignition? | -- | Go to Diagnostic Aids | ||
5 |
Did you find and correct the condition? | -- | ||
6 | Test the KS signal circuit for a poor terminal connection at the knock sensor. Refer to Testing for Continuity , Testing for Intermittent Conditions and Poor Connections , Repairing Connector Terminals , and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
7 | Replace the knock sensor. Refer to Knock Sensor Replacement . Did you complete the replacement? | -- | -- | |
8 |
Does the scan tool indicate DTC P0327 failed this ignition? | -- | System OK |
