NO.18 COOLING SYSTEM CONCERNS-RUNS COLD [ZJ, ZY, Z6]

id0103b1802400

18

COOLING SYSTEM CONCERNS - RUNS COLD
DESCRIPTION
Engine takes excessive period for reaching normal operating temperature.
POSSIBLE CAUSE
•  Thermostat malfunction
•  Condenser fan system malfunction
•  Cooling fan system malfunction

Diagnostic procedure

STEP

INSPECTION

RESULTS

ACTION
1
Is customer complaint "Lack of passenger compartment heat" only?
Yes
Inspect A/C and heater system.
No
Go to the next step.
2
Does engine speed continue at fast idle?
Yes
Go to symptom troubleshooting "No.9 Fast idle/runs on".
(See NO.9 FAST IDLE/RUNS ON[ZJ, ZY, Z6].)
No
Go to the next step.
3
Remove the thermostat and inspect operation.
(See THERMOSTAT REMOVAL/INSTALLATION[ZJ, ZY, Z6].)
(See THERMOSTAT INSPECTION[ZJ, ZY, Z6].)
Is the thermostat normal?
Yes
Go to the next step.
No
Replace the thermostat.
(See THERMOSTAT REMOVAL/INSTALLATION[ZJ, ZY, Z6].)
4
Inspect cooling fan control system operation.
(See ENGINE CONTROL SYSTEM OPERATION INSPECTION[ZJ, ZY, Z6].)
Does cooling fan control system work properly?
Yes
Access ECT PID.
Inspect for both ECT PID and the temperature gauge on the instrument cluster readings.
•  If the temperature gauge on instrument cluster indicates normal range but ECT PID is not same as the temperature gauge reading, inspect the ECT sensor.
•  If the temperature gauge on the instrument cluster indicates cold range but ECT PID is normal, inspect the temperature gauge and the heat gauge unit.
No
Repair or replace the malfunctioning part.
5
Verify test results.
•  If normal, return to diagnostic index to service any additional symptoms.
•  If malfunction remains, inspect related Service information perform repair or diagnosis.
―  If vehicle repaired, troubleshooting completed.
―  If vehicle not repaired or additional diagnostic information not available, replace the PCM.