Diagnostic procedure

DIAGNOSTIC PROCEDURE

STEP	INSPECTION		ACTION
1	Is customer complaint "Lack of passenger compartment heat" only?	Yes	Inspect the A/C heater system.
1		No	Go to the next step.
2	Does the engine speed continue at fast idle?	Yes	Go to symptom troubleshooting "NO.9 FAST IDLE/RUNS ON." (See NO. 9 FAST IDLE/RUNS ON ).
2	Does the engine speed continue at fast idle?	No	Go to the next step.
3	Cool down the engine. Remove the thermostat and inspect operation. (See THERMOSTAT REMOVAL/INSTALLATION ). (See THERMOSTAT INSPECTION ). Is thermostat normal?	Yes	Go to the next step.
3		No	Replace the thermostat.
4	Perform the Cooling Fan Control System Operation Inspection. (See COOLING FAN CONTROL SYSTEM INSPECTION ). Does the cooling fan system operate properly?	Yes	Access the ECT PID using the M-MDS. Inspect for both ECT PID and temperature gauge readings. If the temperature gauge on instrument cluster indicates normal but ECT PID is not same as temperature gauge reading, inspect the ECT sensor. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION ). If the temperature gauge on instrument cluster indicates overheating but ECT PID is normal, inspect the instrument cluster. (See WATER TEMPERATURE GAUGE ).
4		No	Repair or replace malfunctioning part, according to inspection results.
5	Verify test results. If normal, return to the diagnostic index to service any additional symptoms. If a malfunction remains, inspect the related Service Bulletins and/or On-line Repair Information and perform the repair or diagnosis. If the vehicle is repaired, troubleshooting is completed. If the vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.