Circuit Description
The knock sensor system detects for an engine detonation. The knock sensor produces an AC voltage signal. This signal then travels to the KS module that is an internal part of the PCM. The amplitude and the frequency of the AC voltage signal is dependent upon the knock level being detected. Then, the PCM will retard the spark timing based on the signals from the KS module.
Conditions for Setting the DTC
| • | The engine run time is greater than 20 seconds. |
| • | The Engine Coolant Temperature (ECT) is greater than 56°C (133°F). |
| • | The KS voltage is less than 1.0 V or greater than 4.99 V. |
| • | The engine speed is above 2200 RPM. |
| • | DTC(s) P0107, P0108 are not set. |
| • | The MAP is greater than 60 kPa. |
| • | The above conditions are present for greater than 60 seconds. |
Action Taken When the DTC Sets
| • | The Malfunction Indicator Lamp (MIL) will illuminate. |
| • | The PCM will record operating conditions at the time the diagnostic fails. This information will store in the Freeze Frame and Failure Records buffers. |
| • | A history DTC stores. |
| • | The coolant fan turns ON. |
| • | The PCM will default to 6 degrees timing. |
Conditions for Clearing the MIL/DTC
| • | The MIL will turn OFF after three consecutive ignition cycles in which the diagnostic runs without a fault. |
| • | A history DTC will clear after 40 consecutive warm-up cycles without a fault. |
| • | The MIL/DTCs can be cleared by using the scan tool. |
Diagnostic Aids
| • | Check and correct any abnormal engine noise before using the diagnostic table. |
| • | Thoroughly check any suspected circuitry for the following conditions: |
| - | Backed out terminals |
| - | Improper mating |
| - | Broken locks |
| - | Improperly formed connectors |
| - | Damaged terminals |
| - | Poor terminal to wiring connections |
| - | Physical damage to the wiring harness |
Test Description
The number(s) below refer(s) to the step number(s) on the Diagnostic Table.
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The Powertrain OBD System Check prompts you to complete some of the basic checks and to store the freeze frame and failure records data on the scan tool if applicable. This creates an electronic copy of the data captured when the this DTC set. The scan tool stores this data for later reference.
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If the conditions for the test as described above are met, a DTC P0325 will set and the MIL will illuminate.
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If the engine has an internal knock or an audible noise that causes a knocking type of noise on the engine block, this is an indication that the knock sensor may be responding to the noise.
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This step checks the internal resistance of the knock sensor or the wiring to the knock sensor.
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Thoroughly check any suspected circuitry for the following conditions:
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Reprogram the replacement PCM and perform the crankshaft position system variation learning procedure. Refer to the latest Techline information for PCM programming and the Powertrain Control Module (PCM) for the crankshaft position system variation learning procedure.
| • | Backed out terminals |
| • | Improper mating |
| • | Broken locks |
| • | Improperly formed or damaged terminals |
| • | Poor terminal to wiring connections |
| • | Physical damage to the wiring harness |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | Go to | ||
Does the Malfunction Indicator Lamp (MIL) illuminate? | 120 seconds | |||
3 |
Does the Malfunction Indicator Lamp (MIL) illuminate? | -- | ||
Listen to the engine while raising and lowering the engine speed. Is a knock or audible noise present? | -- | |||
5 | Repair the mechanical engine problem, or a loose bracket, or a component. Is the action complete? | -- | -- | |
Is the measured value within the specified value? | 90K-110Kohms | |||
Check the knock sensor signal circuit for a poor electrical connection at the PCM. Repair the circuit. Was a repair necessary? | -- | |||
Replace the PCM. Is the action complete? | -- | -- | ||
9 | Check the knock sensor electrical connector for a poor electrical connection. Repair the connector. Was a repair necessary? | -- | ||
10 | Check the knock sensor signal circuit for an open, for a short to ground, or for a short to voltage. Repair the circuit as necessary. Was a repair necessary? | -- | ||
11 | Replace the Knock Sensor (KS). Is the action complete? | -- | -- | |
12 |
Does the scan tool indicate that this diagnostic has ran and passed? | -- | ||
13 | Check to see if any DTCs are set. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to applicable DTC table | System OK |
