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

-
DTC detecting condition:

Immediately at fault recognition

Trouble symptom:
- Coolant temperature rises slowly
- Poor acceleration
Wiring diagram:

Engine Electrical system. Refer to WIRING SYSTEM>ENGINE ELECTRICAL SYSTEM .

Courtesy of SUBARU OF AMERICA, INC.

CAUTION: Use the check board when measuring the ECM terminal voltage and resistance. Refer to ENGINE (DIAGNOSTICS) (H4DO)>GENERAL DESCRIPTION>PREPARATION TOOL>HOW TO USE CHECK BOARD .

NOTE: After the faulty parts are repaired or replaced, perform the final check in Basic Diagnostic Procedure. Refer to ENGINE (DIAGNOSTICS) (H4DO)>Basic Diagnostic Procedure>PROCEDURE .

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]. Refer to COMMON (DIAG)>CLEAR MEMORY .
3. Using the Subaru Select Monitor or a general scan tool, read the DTC of [Engine]. Refer 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.
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 & 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.
CHECK THERMO-CONTROL VALVE ASSEMBLY MOTOR .
Measure the resistance between the ECM connector and engine ground.

Connector & 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.
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 & 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.
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 & 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.
CHECK THERMO-CONTROL VALVE ASSEMBLY CONNECTOR HARNESS (SHORT BETWEEN LINES) .
Measure the resistance between thermo-control valve assembly connectors.

Connector & terminal

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

Is the resistance 1 MΩ or more?

Yes : Replace the thermo-control valve assembly. Refer 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.