DTC P0327 Knock Sensor (KS) Circuit. Oldsmobile Shelby Series 1 1999

For 1990-2009 cars
Engine Controls Components
Ignition Control Module
OBD II Symbol Description Notice
Powertrain Control Module Connector End Views
Handling ESD Sensitive Parts Notice

### Circuit Description

The knock sensor (KS) system detects engine pre-detonation. The powertrain control module (PCM) retards the spark timing based on the signal from the KS. The KS produces an AC voltage when specific frequencies are detected. The KS voltages are an input to the PCM. The amount of AC voltage produced is proportional to the intensity of the knock.

An operating engine produces a normal amount of engine mechanical vibration or noise. The KS produces an AC voltage signal from this noise. When an engine operates, the PCM learns the minimum and maximum frequency of the noise the engine produces. When the PCM determines that this frequency is less than or more than the expected amount, a knock sensor DTC will set.

### Conditions for Running the DTC

• | The engine speed is between 1,500 RPM and 3,000 RPM.

• | The engine coolant temperature is more than 60°C (135°F).

• | The throttle angle is more than 0.5 percent.

• | The engine run time is more than 20 seconds.

### Conditions for Setting the DTC

The PCM determines that this frequency is less than or more than the expected amount for less than 3 seconds.

### Action Taken When the DTC Sets

• | The powertrain control module (PCM) stores the DTC information into memory when the diagnostic runs and fails.

• | The malfunction indicator lamp (MIL) will not illuminate.

• | The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records.

### Conditions for Clearing the DTC

• | A last test failed, or current DTC, clears when the diagnostic runs and does not fail.

• | A history DTC will clear after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.

• | Use a scan tool in order to clear the DTC.

### Diagnostic Aids

Important:

• | Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing or replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent contaminant intrusion into the PCM.

• | For any test that requires probing the PCM or component harness connectors, use the J 35616 connector test adapter kit. Using this kit prevents any damage to the harness connector terminals. Refer to Using Connector Test Adapters in Wiring Systems for procedures.

• | Inspect the KS for proper installation. A KS that is loose or over torqued may cause the DTC P0327 to set.

• | For an intermittent, refer to Symptoms .

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. This verifies the malfunction is present. The scan tool will display DTC Ran=Yes and Pass=Int if the failure is intermittent. This indicates the diagnostic passed this ignition cycle and failed this ignition cycle. At this point the resistance of the knock sensors should be verified to be in the correct range. If the KS resistances are correct, inspect the KS system wiring connections. Failure Records data does not include the parameter KS activity, however other parameters may aid in locating the conditions under which an intermittent occurred.

2. This test isolates the KS from the rest of the circuit.

3. Tap on the engine block near the appropriate KS. Do not tap on plastic engine components.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check

2

Important: If an engine knock can be heard, repair the engine mechanical condition before proceeding with this diagnostic.

1. Turn ON the ignition leaving the engine OFF.
2. Review the Freeze Frame and/or Failure Records data for this DTC and observe the parameters.
3. Turn OFF the ignition for 15 seconds.
4. Start the engine.
5. Operate the vehicle within the conditions required for this diagnostic to run, and as close to the conditions recorded in Freeze Frame and/or Failure Records as possible. Special operating conditions that you need to meet before the PCM will run this diagnostic, where applicable, are listed in Conditions for Running the DTC.
6. Monitor the DTC information using a scan tool.

Does the scan tool indicate that this diagnostic failed this ignition?

--

Go to Step 3

Go to Diagnostic Aids

3

1. Disconnect the KS/starter solenoid electrical connector.
2. Measure the resistance between the sensor side of the harness of the KS signal circuit and the battery ground using the DMM.
3. Set the DMM to the 400K ohm scale.

Is the resistance of the KS within the specified range?

93-107K ohms

Go to Step 4

Go to Step 6

4

1. Connect the DMM between the sensor side of the harness of the KS signal circuit and the engine block.
2. Set the DMM to the AC voltage scale.

Important: Do not tap on plastic engine components.

3. Tap on the engine near the KS while observing the signal indicated on the DMM.

Is any signal indicated on the DMM while tapping on the engine near the KS?

--

Go to Step 5

Go to Step 7

5

1. Disconnect the PCM connector C1 located on the same side as the manufacturer logo. Refer to Powertrain Control Module Replacement/Programming .
2. Test the KS signal circuit between the PCM and the KS connector for the following:

• | An open

• | A short to voltage

• | A short to ground

3. If you find a condition, repair the condition as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 10

Go to Step 8

6

1. Remove the intake manifold.
2. Test for an open or a short to ground in the signal circuit between the PCM and the KS connector.

Did you find and correct the condition?

--

Go to Step 10

Go to Step 7

7 | Replace the KS. Refer to Knock Sensor Replacement . Is the action complete? | -- | Go to Step 10 | --

8

1. Inspect for a poor connection at the PCM. Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.
2. If you find a poor connection repair as necessary. Refer to Repairing Connector Terminals in Wiring Systems.

Did you find and repair the condition?

--

Go to Step 10

Go to Step 9

9 | Important:: The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | Go to Step 10 | --

10

1. Select the DTC option and Clear the DTC Information option using the scan tool.
2. Idle the engine at the normal operating temperature.
3. Select the DTC option and the Specific DTC option, then enter the DTC number using the scan tool.
4. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text, if applicable.

Does the scan tool indicate that this test ran and passed?

--

Go to Step 11

Go to Step 2

11 | Select the Capture Info option and the Review Info option using the scan tool. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to the applicable DTC table | System OK