P0324

DTC P0324: Knock Sensor Internal Malfunction

System Description
The Knock Sensor (KS) system is used to detect engine detonation, allowing the Engine Control Module (ECM) to retard the 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 ECM contains a nonreplaceable knock filter module called a Digitally Controlled Signal-to-Noise Enhancement Filter (DSNEF) module. This filter module in the ECM determines whether or not knock is occurring by comparing the signal level on the KS circuit with the voltage level on the noise channel. The noise channel allows the ECM to reject any false knock signal by knowing the amount of normal engine mechanical noise present. Normal engine noise varies depending on engine speed and load. When the ECM determines that an abnormally low noise channel voltage level is being experienced, Diagnostic Trouble Code (DTC) P0324 will set.

Conditions for Setting the DTC
- DSNEF A/D reading is less than 3.9% or greater than 80% any of the 4 cylinders.
- Vacuum is less than the predetermined value (10 to 50 kPa, based on rpm).
- The rpm is greater than 1600.
- Engine Coolant Temperature (ECT) is greater than 50�C (122�F).

Action Taken When the DTC Sets
- The Malfunction Indicator Lamp (MIL) will not illuminate.
- The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Failure Records buffers.
- A history DTC is stored.

Conditions for Clearing the MIL/DTC
- A history DTC will clear after 40 consecutive warm-up cycles without a fault.
- DTC(s) can be cleared by using the scan tool.
- Disconnecting the ECM battery feed for more than 10 seconds.

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

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 P0324 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 knock sensor may be responding to the noise.
(6) The replacement ECM must be reprogrammed. Refer to the latest Techline procedure for ECM reprogramming.

Steps 1-7:

Troubleshooting