Map Controlled Engine Cooling Thermostat - F265-, Checking

General Description

The Map Controlled Engine Cooling Thermostat -F265- can either open mechanically from engine coolant temperature, or from the Engine/Motor Control Module -J623-. Providing power to an electrical element inside the Map Controlled Engine Cooling Thermostat -F265- for more precise operation of the cooling system based on a mapping table that is contained inside the Engine/Motor Control Module -J623-.

Special tools and workshop equipment required

Multimeter.
Wiring Diagram.
Scan Tool.

Test requirements

Fuses OK.
Battery voltage OK.
Switch OFF all electrical and electronic accessories.
Vehicles with automatic transmission, ensure the selector lever position is in "P".
Vehicles with manual transmission, ensure the shifter lever position is in "N" with the parking brake applied.
Observe all safety precautions: SAFETY PRECAUTIONS .
View clean working conditions: CLEAN WORKING CONDITIONS .

Test Procedure

Step	Procedure	Result / Action to Take
1	PERFORM: Preliminary Check to verify the customers complaint. Refer to PRELIMINARY CHECK . -- Was Complaint verified?	-- YES: GO TO: Step 2. -- NO: GATHER more information from customer about the complaint.
2	IGNITION: OFF. DISCONNECT: Map Controlled Engine Cooling Thermostat -F265- harness connector. CHECK: Map Controlled Engine Cooling Thermostat -F265- component connector terminals 1 to 2 for resistance. SPECIFIED VALUE: 5 - 15 Ω (@ approx. 20° C). -- Was Value obtained?	-- YES: GO TO: Step 3. -- NO: REPLACE: Map Controlled Engine Cooling Thermostat -F265-. Refer to appropriate Service Information. GO TO: Step 5.
3	IGNITION: ON. CHECK: Map Controlled Engine Cooling Thermostat -F265- harness connector terminal 1 to ground for voltage. IGNITION: OFF. SPECIFIED VALUE: Battery voltage. -- Was Value obtained?	-- YES: GO TO: Step 4. -- NO: PERFORM: Visual Inspection of wiring and component. CHECK: Wiring for open, high resistance, short or harness connector for damage, corrosion, loose or broken terminals. REPAIR: Faulty wiring or connector. GO TO: Step 5.
4	REMOVE: Engine/Motor Control Module - J623-. Refer to appropriate Service Information. CHECK: Map Controlled Engine Cooling Thermostat -F265- harness connector terminal 2 to the Engine/Motor Control Module -J623- harness connector T56a / 54 for resistance. SPECIFIED VALUE: 0.5 Ω (± 0.3 Ω). -- Was Value obtained?	-- YES: TIP: The Map Controlled Engine Cooling Thermostat -F265- may fail under loaded operation; please swap a known good Map Controlled Engine Cooling Thermostat -F265- prior to continuing to the next step. GO TO: Step 5. -- NO: PERFORM: Visual Inspection of wiring and component. CHECK: Wiring for open, high resistance, short or harness connector for damage, corrosion, loose or broken terminals. REPAIR: Faulty wiring or connector. GO TO: Step 5.
5	Final Procedure Perform a road test to verify repair. -- Does the original DTC return?	-- YES: CHECK: Engine/Motor Control Module -J623- harness connector for any damaged, pushed-out pins. REPAIR: As necessary. If all electrical connections are OK: REPLACE: Engine/Motor Control Module -J623-. Refer to appropriate Service Information. Clear the DTC's. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY . Repair is complete. Generate Readiness Code. Refer to READINESS CODE . Return vehicle to Customer. -- NO: Perform the diagnostic procedure for any DTC's. If no DTC's return, the repair is complete. Return vehicle to customer.