DTC P0327: Knock/Combustion Vibration Sensor 1 Circuit Low Bank 1 Or Single Sensor: Notes

DTC detecting condition: 

Immediately at fault recognition

Trouble symptom: 

• Poor driving performance
• Knocking occurs

Wiring diagram: 

Engine Electrical System Refer to WIRING SYSTEM>ENGINE ELECTRICAL SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK HARNESS BETWEEN ECM AND KNOCK SENSOR CONNECTOR. 
   1. Turn the ignition switch to OFF.
   2. Disconnect the connector from ECM.
   3. Measure the resistance between ECM connectors.

   Connector & terminal 

   (B137) No. 2 - (B134) No. 29:

   Is the resistance less than 500 kΩ?

   Yes:  Go to  2.

   No:  Go to  3.

2. CHECK KNOCK SENSOR. 
   1. Disconnect the connector from the knock sensor.
   2. Measure the resistance between knock sensor connectors.

   Terminals 

   No. 1 - No. 2:

   Is the resistance less than 500 kΩ?

   Yes:  Replace the knock sensor. Refer to FUEL INJECTION (FUEL SYSTEMS) (STI)>KNOCK SENSOR .

   No:  Repair the short circuit to ground in harness between ECM connector and knock sensor connector.

   NOTE: The harness between both connectors are shielded. Remove the shield and repair the short circuit of harness.
3. CHECK INPUT SIGNAL OF ECM. 
   1. Connect the connector to ECM.
   2. Turn the ignition switch to ON.
   3. Measure the voltage between ECM connector and chassis ground.

   Connector & terminal 

   (B137) No. 2 (+) - Chassis ground (-):

   Is the voltage 2 V or more?

   Yes:  Even if DTC is detected, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.

   NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.

   No:  Repair the short circuit to ground in harness between ECM connector and knock sensor connector.

   NOTE: The harness between both connectors are shielded. Remove the shield and repair the short circuit of harness.