NO.18 COOLING SYSTEM CONCERNS-RUNS COLD [LF, L5]


id010397802400

18

COOLING SYSTEM CONCERNS-RUNS COLD

DESCRIPTION
•  The engine does not reach normal operating temperature.
POSSIBLE CAUSE
•  Thermostat malfunction
•  Cooling fan system malfunction
•  PCM malfunction

Diagnostic procedure

STEP

INSPECTION

RESULTS

ACTION

1
Is the customer complaint “Lack of passenger compartment heat” only?
Yes
Inspect the A/C and heater system.
Repair or replace the malfunctioning part according to the inspection results.
No
Go to the next step.
2
Does the engine speed continue at fast idle?
Yes
Go to the symptom troubleshooting “NO.9 FAST IDLE/RUNS ON”.
No
Go to the next step.
3
Cool down the engine.
Remove the thermostat and inspect operation.
Is the thermostat normal?
Yes
Go to the next step.
No
Replace the thermostat.
4
Perform the Cooling Fan Control System Inspection.
Does the cooling fan control system function properly?
Yes
Access the ECT PID using the M-MDS.
Inspect for both the ECT PID and the low engine coolant temperature indicator light condition.
•  If the low engine coolant temperature indicator light on the instrument cluster turns off but the ECT PID is not same as the low engine coolant temperature indicator light condition:
―  Replace the ECT sensor, if necessary.
•  If the low engine coolant temperature indicator light on the instrument cluster indicates overheating but the ECT PID is normal:
―  Inspect the instrument cluster.
―  Replace the instrument cluster, if necessary.
No
Repair or replace the malfunctioning part according to the inspection results.
5
•  Verify the test results.
―  If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [LF, L5].)
―  If a malfunction remains, inspect the related Service Information perform repair or diagnosis.
•  If the vehicle repaired, troubleshooting is completed.
•  If the vehicle not repaired or additional diagnostic information not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [LF, L5].)