P0327

P0327 Knock Sensor Circuit Fault




System Description
The Knock Sensor (KS) system is used to detect engine detonation, allowing the powertrain control module (PCM)/engine control module (ECM) to retard ignition control spark timing based on the KS signal being received. The KS produces an AC signal so that under a no knock condition the signal on the KS circuit measures about 0.007 volts AC. The KS signal's amplitude and frequency depend upon the amount of knock being experienced. The PCM/ECM monitors the KS signal and can diagnose the KS sensor and circuitry.

Conditions for Setting the DTC
- All cylinder gain is greater than 191 and the rpm is less than 6375.
- KS voltage on all cylinders is less than 0.2 volt for AT and less than 0.35 volt for MT and all cylinder gain is greater than 191, and Engine Coolant Temperature (ECT) is greater than 50 °C (122 °F).
- Vacuum is less than 10 to 50 kPa based on rpm.
- The rpm is greater than 2000 for AT and greater than 1600 for MT

Action Taken When the DTC Sets
- The Malfunction Indicator Lamp (MIL) will illuminate.
- The PCM/ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers.
- A history DTC is stored.
- The PCM/ECM will use a calculated spark retard value to minimize knock during conditions when knock is likely to occur. The calculated value will vary based on engine speed and load.

Conditions for Clearing the MIL/DTC
- The MIL will turn off after three consecutive ignition cycles in which the diagnostic runs without a fault within the freeze frame conditions that the DTC failed.
- A history DTC will clear after 40 consecutive warm-up cycles without a fault.
- DTC(s) can be cleared by using the scan tool.

Diagnostic Aids
Check and correct any abnormal engine noise before using the diagnostic table.

Any circuitry, that is suspected as causing the complaint, should be thoroughly checked for the following conditions:
- Backed-out terminals
- Improper mating
- Broken locks
- Improperly formed
- Damaged terminals
- Poor terminal-to-wire connection
- Physical damage to the wiring harness

Step 1 - 7:

Step 8 - 13:

Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
1. The On-Board Diagnostic (OBD II) System Check prompts the technician to complete some basic checks and store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data taken when the malfunction occurred. The information is then stored on the scan tool for later reference.
2. If the conditions for the test as described above are met, a DTC P0327 will set and MIL will illuminate.
4. If the engine has an internal knock or audible noise that causes a knocking type noise on the engine block, the KS may be responding to the noise.
6. Checking the internal resistance of the KS or the wiring to the KS is OK.
7. Any circuitry, that is suspected as causing the complaint, should be thoroughly checked for backed-out terminals, improper mating, broken locks improperly formed or damaged terminals, poor terminal-to-wiring connections or physical damage to the wiring harness.
8. The replacement PCM/ECM must be reprogrammed. Refer to the latest Techline procedure for PCM/ECM reprogramming.
7. Any circuitry, that is suspected as causing the complaint, should be thoroughly checked for backed-out terminals, improper mating, broken locks improperly formed or damaged terminals, poor terminal-to-wiring connections or physical damage to the wiring harness.
8. The replacement PCM/ECM must be reprogrammed. Refer to the latest Techline procedure for PCM/ECM reprogramming.