Circuit Description
The knock sensor (KS) system detects for an engine detonation. The knock sensor produces an AC voltage signal. The amplitude and the frequency of the AC voltage signal is dependent upon the knock level being detected. This signal then travels to the KS module that is an internal part of the Powertrain Control Module (PCM). If knock is detected, the PCM will retard the spark timing based on the signal from the knock sensor.
Conditions for Running the DTC
| • | Engine run time is more than 20 seconds. |
| • | Engine Coolant Temperature (ECT) is more than 56°C (131°F). |
| • | Engine speed is above 1600 RPM. |
| • | MAP is more than 60 kPa. |
| • | Engine vacuum is less than 33 kPa. |
Conditions for Setting the DTC
| • | The KS voltage and variation is not within normally expected ranges. |
| • | The above conditions are present for more than 60 seconds. |
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) if a failure is detected during 2 consecutive key cycles. |
| • | The control module sets the DTC and records the operating conditions at the time the diagnostic failed. The failure information is stored in the scan tool Freeze Frame/Failure Records. |
Conditions for Clearing the MIL or DTC
| • | The control module turns OFF the MIL after 3 consecutive drive trips when the test has run and passed. |
| • | A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles. A warm-up cycle occurs when the coolant temperature has risen 22°C (40°F) from the startup coolant temperature and the engine coolant reaches a temperature that is more than 70°C (158°F) during the same ignition cycle. |
| • | Use a scan tool in order to clear the DTCs. |
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 |
An intermittent may be caused by any of the following conditions:
| • | A poor connection |
| • | Rubbed through wire insulation |
| • | A broken wire inside the insulation |
Thoroughly check any circuitry that is suspected of causing the intermittent complaint. Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.
If a repair is necessary, refer to Wiring Repairs or Connector Repairs in Wiring Systems.
Test Description
The numbers below refer to the step numbers 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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Reprogram the replacement PCM and perform the Crankshaft Position System Variation Learn Procedure. Refer to the latest Techline information for PCM programming.
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? | -- | |||||||||
Listen to the engine while raising and lowering the engine speed. Is a knock or audible noise present? | -- | |||||||||
4 |
Is the action complete? | -- | -- | |||||||
Is the measured value within the specified value? | 90K-110Kohms | |||||||||
6 |
Was a repair necessary? | -- | ||||||||
|
Important:: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Is the action complete? | -- | -- | ||||||||
8 |
Was a repair necessary? | -- | ||||||||
9 |
Was a repair necessary? | -- | ||||||||
10 | Replace the Knock Sensor (KS). Refer to the Knock Sensor Replacement . Is the action complete? | -- | -- | |||||||
11 |
Does the scan tool indicate that this diagnostic has ran and passed? | -- | ||||||||
12 | Check to see if any DTCs are set. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to the applicable DTC table | System OK |
