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.

CAUTION: Use the check board when measuring the ECM terminal voltage and resistance. Ref. 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. Ref. 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]. 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.
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

(E158) No. 82 (+) - Engine ground (-):

(E158) 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 and terminal

(E158) No. 82 - Engine ground:

(E158) No. 91 - Engine ground:

Is the resistance 1MΩ 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 and terminal

(E158) No. 82 (+) - Engine ground(-):

(E158) 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 a terminal

(E158) No. 82 - Engine ground:

(E158) No. 91 - Engine ground:

Is the resistance 1MΩ 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 a terminal

(E164) No. 4 - (E164) No. 5:

Is the resistance 1MΩ 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.