Engine Coolant Temperature Light Blinks In Red And Blue Alternately

Trouble causes: 

• CAN communication failure
• Engine coolant temperature sensor malfunction
• Combination meter malfunction

1. CHECK DTC  .
   1. Turn the ignition switch to ON.
   2. Read the DTC of [Engine] using the Subaru Select Monitor. Ref. to ENGINE (DIAGNOSTICS) (H4DO 2.5)>DIAGNOSTIC TROUBLE CODE (DTC) . Ref. to ENGINE (DIAGNOSTICS) (H4DO 2.0 (EXCEPT FOR HEV))>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is any of [ENGINE COOLANT TEMPERATURE SENSOR 1 CIRCUIT RANGE/PERFORMANCE], [ENGINE COOLANT TEMPERATURE SENSOR 1 CIRCUIT LOW], [ENGINE COOLANT TEMPERATURE SENSOR 1 CIRCUIT HIGH] displayed? (Current malfunction)

   Yes:  Perform the diagnosis for the displayed DTCs. Ref. to ENGINE (DIAGNOSTICS) (H4DO 2.5)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST . Ref. to ENGINE (DIAGNOSTICS) (H4DO 2.0 (EXCEPT FOR HEV))>DIAGNOSTIC TROUBLE CODE (DTC)>LIST .

   No:  Go to  2.

2. CHECK DTC  .
   1. Start the engine.
   2. Using the Subaru Select Monitor, read all DTCs. Ref. to LAN SYSTEM (DIAGNOSTICS) (EXCEPT FOR HEV)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC U**** displayed? (Current malfunction)

   Yes:  Perform the diagnosis according to the basic diagnostic procedure in LAN SYSTEM (DIAGNOSTICS). Ref. to LAN SYSTEM (DIAGNOSTICS) (EXCEPT FOR HEV)>BASIC DIAGNOSTIC PROCEDURE .

   No:  Go to  3.

3. CHECK THE ENGINE COOLANT TEMPERATURE LIGHT  .

   Using the Subaru Select Monitor, check the following items in the [Active Test] of [Combination Meter]. Ref. to COMBINATION METER (DIAGNOSTICS)>ACTIVE TEST .

   • Water temperature (HOT)
   • Water temperature (COOL)

   Do the indicated amount on Subaru Select Monitor and the engine coolant temperature light indication match?

   Yes:  Perform a unit inspection of the engine coolant temperature sensor. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO (EXCEPT FOR HEV))>ENGINE COOLANT TEMPERATURE SENSOR .

   No:  Replace the combination meter. Ref. to INSTRUMENTATION/DRIVER INFO>COMBINATION METER .