Circuit Description
The PCM contains integrated knock sensor (KS) diagnostic circuitry. The PCM uses the circuitry to diagnose the KS sensors and related wiring. The PCM calculates an average voltage of each knock sensors signals and takes instantaneous signal voltage readings. The PCM uses the instantaneous signal voltage readings to determine the state of the knock sensor circuitry. If the knock sensor system is operating normally, the PCM should monitor instantaneous KS signal voltage readings varying outside a voltage range above and below the calculated average voltage. If the PCM detects a knock sensor 1 signal voltage within the calculated average voltage range, DTC P0327 will set.
Conditions for Running the DTC
| • | No TP, VSS, CKP sensor, CMP sensor, MAF sensor, or ECT sensor DTCs are set. |
| • | Engine speed is between 1000 and 2500 RPM: |
| • | Throttle angle is more than 10 percent. |
| • | Engine load is more than 45 percent. |
| • | Engine coolant temperature is more than 60°C (140°F). |
| • | Maximum spark retard is less than 15 degrees. |
| • | System voltage is more than 9 volts. |
Conditions for Setting the DTC
| • | The PCM detects a knock sensor 1 signal voltage within the calculated average voltage range. |
| • | The condition is present for 300 3X reference periods (100 crankshaft revolutions). |
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/Failure Records data. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn OFF the malfunction indicator lamp (MIL) during the third consecutive trip in which the diagnostic has 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 a scan tool. |
Diagnostic Aids
Inspect for the following:
Many situations may lead to an intermittent condition. Perform each inspection or test as directed.
Important: : Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.
| • | Loose terminal connection |
| - | Use a corresponding mating terminal to test for proper tension. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| - | Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Refer to Testing for Intermittent Conditions and Poor Connections , and to Connector Repairs in Wiring Systems for diagnosis and repair. |
| • | Damaged harness--Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
| • | Inspect the powertrain control module (PCM) and the engine grounds for clean and secure connections. Refer to Wiring Repairs in Wiring Systems for diagnosis and repair. |
If the condition is determined to be intermittent, reviewing the Snapshot or Freeze Frame/Failure Records may be useful in determining when the DTC or condition was identified.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This verifies the malfunction is present. The scan tool will indicate 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 knock sensor resistances are correct, test the KS system wiring connections. When inspecting the KS system connections, start at the KS system jumper harness connector located behind the intake manifold. Then inspect the connections at the PCM. Review the wiring schematic for the correct connector and terminal. Then inspect the connections at the appropriate knock sensor. Failure Records data does not include the parameter KS Activity, however other parameters may aid in locating the conditions under which an intermittent occurred.
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This test will isolate the knock sensor from the rest of the circuit.
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Tap on the engine block in the location of the appropriate knock sensor.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
|
Important: If an engine knock can be heard, repair the engine mechanical problem before proceeding with this diagnostic.
Does the scan tool indicate that this DTC failed this ignition? | -- | Go to Diagnostic Aids | ||
Does the resistance measure within the specified range? | 93-107Kohms | |||
Does the scan tool indicate a signal while tapping on the engine near the knock sensor? | -- | |||
5 | Test the KS signal circuit for an open, a short to voltage or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
6 | Replace the knock sensor. Refer to Knock Sensor Replacement . Did you complete the replacement? | -- | -- | |
7 | Inspect the KS signal circuit for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
8 |
Important:: The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Did you complete the replacement? | -- | -- | |
9 |
Does the DTC reset? | -- | ||
10 | Does the scan tool indicate any DTCs that you have not diagnosed? | -- | Go to applicable DTC | System OK |
