DTC P2682: Engine Coolant Bypass Valve "A" Control Circuit Low: Notes

1. - 

DTC detecting condition: 

Immediately at fault recognition

Trouble symptom: 

• Coolant temperature rises slowly
• Poor acceleration

Wiring diagram: 

Engine Electrical System Ref. to WIRING SYSTEM>ENGINE ELECTRICAL SYSTEM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK DTC  .
   1. Turn the ignition switch to ON.
   2. Using the Subaru Select Monitor or a general scan tool, perform the clear memory of [Engine]. Ref. to COMMON (DIAG)>CLEAR MEMORY .
   3. Using the Subaru Select Monitor or a general scan tool, read the DTC of [Engine]. Ref. to COMMON (DIAG)>DIAGNOSTIC TROUBLE CODE (DTC) .

      Is DTC P2682 displayed? (Current malfunction)

      Yes  : Go to  2 .

      No  : 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.
2. CHECK THERMO-CONTROL VALVE ASSEMBLY MOTOR  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the connector from ECM.
   3. Measure the voltage between ECM connector and engine ground.

      Connector and terminal 

      (E53) No. 82 (+) - Engine ground (-):

      (E53) No. 91 (+) - Engine ground (-):

      Is the voltage 5 V or more?

      Yes  : Go to  4 .

      No  : Go to  3 .

3. CHECK THERMO-CONTROL VALVE ASSEMBLY MOTOR  .

   Measure the resistance between the ECM connector and engine ground.

   Connector and terminal 

   (E53) No. 82 - Engine ground:

   (E53) No. 91 - Engine ground:

   Is the resistance 1 MΩ or more?

   Yes  : Go to  6 .

   No  : Go to  5 .

4. CHECK HARNESS BETWEEN ECM AND THERMO-CONTROL VALVE ASSEMBLY CONNECTOR (SHORT TO POWER SUPPLY)  .
   1. Disconnect the connector from the thermo-control valve assembly.
   2. Measure the voltage between ECM connector and engine ground.

      Connector and terminal 

      (E53) No. 82 (+) - Engine ground (-):

      (E53) No. 91 (+) - Engine ground (-):

      Is the voltage 5 V or more?

      Yes  : Repair the short circuit to power supply in the harness between the ECM connector and thermo-control valve assembly connector.

      No  : Go to  6 .

5. CHECK HARNESS BETWEEN ECM AND THERMO-CONTROL VALVE ASSEMBLY CONNECTOR (SHORT CIRCUIT TO GROUND)  .
   1. Disconnect the connector from the thermo-control valve assembly.
   2. Measure the resistance between the ECM connector and engine ground.

      Connector and terminal 

      (E53) No. 82 - Engine ground:

      (E53) No. 91 - Engine ground:

      Is the resistance 1 MΩ or more?

      Yes  : Go to  6 .

      No  : Repair the short circuit to ground in the harness between the ECM connector and thermo-control valve assembly connector.

6. CHECK THERMO-CONTROL VALVE ASSEMBLY CONNECTOR HARNESS (SHORT BETWEEN LINES)  .

   Measure the resistance between thermo-control valve assembly connectors.

   Connector and terminal 

   (E119) No. 4 - (E119) No. 5:

   Is the resistance 1 MΩ or more?

   Yes  : Replace the thermo-control valve assembly. Ref. to COOLING (H4DO)>THERMO CONTROL VALVE ASSEMBLY .

   No  : Repair the short between lines in the harness between the ECM connector and thermo-control valve assembly connector.