P1490

DTC P1490 - THERMOSTAT MALFUNCTION

DTC DETECTING CONDITION:
- Immediately at fault recognition

TROUBLE SYMPTOM:
- Thermostat remains open.

CAUTION: After repair or replacement of faulty parts, conduct CLEAR MEMORY MODE and INSPECTION MODEM, Refer to How to Clear Diagnostic Trouble Codes. Clear Memory Mode

10CM1: CHECK VEHICLE CONDITION.

CHECK: Has engine operated at idle or has vehicle been driven with part of engine submerged under water?

YES: In this case, it is not necessary to inspect DTC P1490.

NO: Go to step 10CM2.

10CM2: CHECK ANY OTHER DTC ON DISPLAY.

CHECK: Does the Subaru Select Monitor or OBD-II general scan tool indicate DTC P0125, P0301, P0302, P0303 and P0304 at same time?

YES: Go to step 10CM3.

NO: Inspect DTC P0125, P0301, P0302, P0303 and P0304 using "10. Diagnostics Chart with Trouble Code". P0125 P0304

10CM3: CHECK ENGINE COOLANT.

CHECK: Are coolant level and mixture ratio of cooling water to anti-freeze solution correct?

YES: Go to step 10CM4.

NO: Replace engine coolant.

10CM4: CHECK RADIATOR FAN.
1. Start the engine.
2. Check radiator fan operation.

CHECK: Does radiator fan continuously rotate for more than 3 minutes during idling?

YES: Repair radiator fan circuit.

NO: Replace thermostat.