NO.12 COOLING SYSTEM CONCERNS-RUNS COLD [MZ-CD 1.6]

id0103e4854500

12

Cooling system concerns-Runs cold
DESCRIPTION
•  Engine does not reach normal operating temperature.
POSSIBLE CAUSE
•  Cooling system related DTC is detected.
•  Electrical connector, wiring harness or component damaged
•  Cooling fan relay malfunction
•  Cooling fan motor malfunction
•  Improper indication of low engine coolant temperature indicator light and high engine coolant temperature warning light
―  ECT sensor malfunction
―  Instrument cluster malfunction
•  Thermostat malfunction

Diagnostic procedure

STEP

INSPECTION

RESULTS

ACTION
1
VERIFY PCM DTC
•  Perform the PCM DTC inspection using the M-MDS.
•  Are any cooling system related DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE [MZ-CD 1.6].)
No
Go to the next step.
2
VISUALLY INSPECT RELATED PART CONDITION
•  Visually inspect the following:
Electrical:
―  Fuse(s)
―  Relay(s)
―  Wiring harness
―  Electrical connector(s) (PCM, ECT sensor, cooling fan motor)
―  Cooling fan motor
―   ECT sensor
•  Is there any malfunction?
Yes
Repair or replace the malfunctioning part according to the inspection results.
Repeat Step 2.
No
Go to the next step.
3
INSPECT COOLING FAN RELAY
•  Inspect the cooling fan relays.
•  Are cooling fan relays normal?
Yes
Go to the next step.
No
Replace suspect relay.
4
INSPECT COOLING FAN MOTOR
•  Inspect the cooling fan motor.
•  Is the cooling fan motor normal?
Yes
Go to the next step.
No
Replace the cooling fan motor.
(See COOLING FAN MOTOR REMOVAL/INSTALLATION [MZ-CD 1.6].)
5
INSPECT ECT SENSOR SIGNAL
•  Access the ECT PID using the M-MDS.
•  Compare the ECT PID and low engine coolant temperature indicator light and high engine coolant temperature warning light operation.
•  Is the ECT PID value same as indicator/warning light readings?
Yes
Replace the thermostat.
(See THERMOSTAT REMOVAL/INSTALLATION [MZ-CD 1.6].)
No
Go to the symptom troubleshooting “NO.9 LOW ENGINE COOLANT TEMPERATURE INDICATOR LIGHT /HIGH ENGINE COOLANT TEMPERATURE WARNING LIGHT ILLUMINATES OR FLUSHES CONTINUOUSLY”.
(See NO. 9 LOW ENGINE COOLANT TEMPERATURE INDICATOR LIGHT/HIGH ENGINE COOLANT TEMPERATURE WARNING LIGHT ILLUMINATES OR FLASHES CONTINUOUSLY [INSTRUMENT CLUSTER].)
6
Verify test results.
•  If normal, return to the diagnostic index to service any additional symptoms.
•  If the malfunction remains, inspect the related Service 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.