DTC P0327 Knock Sensor (KS) Circuit. Buick GL7 (Export) 2000

For 1990-2009 cars

### Circuit Description

The powertrain control module (PCM) contains integrated knock sensor (KS) diagnostic circuitry. An input signal from the KS is used to detect engine detonation, allowing the PCM to retard ignition control (IC) spark timing based on the amplitude and the frequency of the KS signal. The KS produces an AC signal under all engine operating conditions. During engine operation, the PCM calculates the average voltage of the KS signal. If the knock sensor system is operating normally, the PCM will sense the KS signal voltage vary above and below the calculated voltage average. If the PCM detects a KS input signal equal to the KS average voltage over 95 percent of a calibrated time, DTC P0327 will set.

### Conditions for Running the DTC

• | No TP, CMP, CKP, CMP, ECT, or VSS DTCs are set.

• | The engine speed is between 1000 and 5000 RPM.

• | The engine has been running for a minimum of 30 seconds.

• | The throttle angle is more than 15 percent.

• | The engine load is more than 45 percent.

• | The engine coolant temperature (ECT) is more than 60°C (140°F).

• | The maximum spark retard is less than 15 degrees.

• | The system voltage is more than 9.0 volts.

### Conditions for Setting the DTC

The PCM detects a KS signal voltage within the calculated average voltage range for at least 10 seconds.

### Action Taken When the DTC Sets

• | The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.

• | The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.

### Conditions for Clearing the MIL/DTC

• | The PCM will turn OFF the MIL during the third consecutive trip in which the diagnostic has been run and passed.

• | The History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.

• | The DTC can be cleared by using the scan tool.

### Diagnostic Aids

Inspect for the following conditions:

• | A poor connection at the PCM. Inspect the KS and PCM connectors for the following conditions. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems:

- | Backed-out terminals

- | Broken locks

- | Improperly formed or damaged terminals

• | A misrouted harness. Inspect the KS harness to ensure that the harness is not routed too closely to high voltage wires such as the spark plug leads.

Reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.

### Test Description

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

1. Verifies that the malfunction is present.

2. If both the 24X crank sensor and the cam signal are not present the KS signal will stop updating and may set DTC P0327. The ignition positive voltage supply and the ground circuits need to be diagnosed using the DTC P0336.

3. If you were sent here from Symptoms, proceed with the diagnostic table.

#### DTC P0327 - Knock Sensor Circuit

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 a mechanical engine knock can be heard, repair the engine mechanical problem before proceeding with this diagnostic. Refer to Engine Noise Diagnosis in Engine Mechanical.

1. Operate the engine within the conditions specified in Conditions for Setting the DTC.
2. Using a scan tool, monitor the Specific DTC info for DTC P0327 until the DTC P0327 test runs.

Does the scan tool indicate DTC P0327 failed this ignition?

--

Go to Step 3

Go to Diagnostic Aids

3 | Using a scan tool, monitor the 24X crank sensor and the CAM signal. Are the 24X signal and the CAM signal present? | -- | Go to Step 4 | Go to DTC P0336 Crankshaft Position (CKP) Sensor Circuit

4

1. Turn ON the ignition switch, leaving the engine OFF.
2. Review and record the scan tool Failure Records data for DTC P0327.
3. Operate the vehicle within the Failure Records conditions.
4. Using a scan tool, monitor the Specific DTC info for DTC P0327 until the DTC P0327 test runs.

Does the scan tool indicate DTC P0327 failed this ignition?

--

Go to Step 5

Go to Diagnostic Aids

5

1. Disconnect the PCM and the KS.
2. Test the KS circuit for opens, shorts to ground, and a short to voltage.
3. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find a problem?

--

Go to Step 8

Go to Step 6

6

1. Inspect the KS signal circuit for a poor terminal connection at the knock sensor.
2. If a problem is found, repair as necessary. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Did you find a problem?

--

Go to Step 8

Go to Step 7

7 | Replace the knock sensor. Refer to Knock Sensor Replacement . Is the action complete? | -- | Go to Step 8 | --

8

1. Review and record the Failure Records data.
2. Clear the DTCs.
3. Operate the vehicle within the Failure Records conditions.
4. Using a scan tool, monitor the Specific DTC info for DTC P0327 until the DTC P0327 test runs.

Does the scan tool indicate DTC P0327 failed this ignition?

--

Go to Step 2

System OK