NO.18 COOLING SYSTEM CONCERNS-RUNS COLD [MZR 2.0 DISI i-stop]

18	COOLING SYSTEM CONCERNS-RUNS COLD
DESCRIPTION	• Engine does not reach normal operating temperature.
POSSIBLE CAUSE	• Condenser fan system malfunction • Thermostat malfunction • Cooling fan system malfunction • Improper indication of low engine coolant temperature indicator light and/or high engine coolant temperature warning light ― ECT sensor malfunction ― Instrument cluster malfunction

COOLING SYSTEM CONCERNS-RUNS COLD

DESCRIPTION

• Engine does not reach normal operating temperature.

POSSIBLE CAUSE

• Condenser fan system malfunction

• Thermostat malfunction

• Cooling fan system malfunction

• Improper indication of low engine coolant temperature indicator light and/or high engine coolant temperature warning light

― ECT sensor malfunction

― Instrument cluster malfunction

STEP	INSPECTION	RESULTS	ACTION
1	Is a customer complaint “Lack of passenger compartment heat” only?	Yes	Inspect the A/C 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	Perform the symptom troubleshooting “NO.9 FAST IDLE/RUNS ON”. (See NO.9 FAST IDLE/RUNS ON [MZR 2.0 DISI i-stop].)
No	Go to the next step.
3	Perform the Cooling Fan Control System Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 2.0 DISI i-stop].) Does the cooling fan control system operate properly?	Yes	Go to the next step.
No	Repair or replace the malfunctioning part according to the inspection results.
4	Cool down the engine. Remove the thermostat. (See THERMOSTAT REMOVAL/INSTALLATION [MZR 2.0 DISI i-stop].) Inspect the thermostat operation. (See THERMOSTAT INSPECTION [MZR 2.0 DISI i-stop]) Is there any malfunction?	Yes	Replace the thermostat. (See THERMOSTAT REMOVAL/INSTALLATION [MZR 2.0 DISI i-stop].)
No	Reinstall the thermostat, then go to the next step. (See THERMOSTAT REMOVAL/INSTALLATION [MZR 2.0 DISI i-stop].)
5	Access the ECT PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZR 2.0 DISI i-stop].) 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	Go to the next step.
No	Inspect the ECT sensor. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION [MZR 2.0 DISI i-stop].) • If there is any malfunction: ― Replace the ECT sensor. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION [MZR 2.0 DISI i-stop].) • If there is no malfunction: ― Perform the instrument cluster symptom troubleshooting “NO. 10 LOW ENGINE COOLANT TEMPERATURE INDICATOR LIGHT/HIGH ENGINE COOLANT TEMPERATURE WARNING LIGHT ILLUMINATES OR FLASHES CONTINUOUSLY”. (See NO. 10 LOW ENGINE COOLANT TEMPERATURE INDICATOR LIGHT/HIGH ENGINE COOLANT TEMPERATURE WARNING LIGHT ILLUMINATES OR FLASHES CONTINUOUSLY [INSTRUMENT CLUSTER].)
6	Verify the test results. • If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZR 2.0 DISI i-stop].) • If a 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, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZR 2.0 DISI i-stop].)

STEP

INSPECTION

RESULTS

ACTION

Is a customer complaint “Lack of passenger compartment heat” only?

Yes

Inspect the A/C heater system.

Repair or replace the malfunctioning part according to the inspection results.

Go to the next step.

Does the engine speed continue at fast idle?

Yes

Perform the symptom troubleshooting “NO.9 FAST IDLE/RUNS ON”.

(See NO.9 FAST IDLE/RUNS ON [MZR 2.0 DISI i-stop].)

Go to the next step.

Perform the Cooling Fan Control System Inspection.

(See ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZR 2.0 DISI i-stop].)

Does the cooling fan control system operate properly?

Yes

Go to the next step.

Repair or replace the malfunctioning part according to the inspection results.

Cool down the engine.

Remove the thermostat.

(See THERMOSTAT REMOVAL/INSTALLATION [MZR 2.0 DISI i-stop].)

Inspect the thermostat operation.

(See THERMOSTAT INSPECTION [MZR 2.0 DISI i-stop])

Is there any malfunction?

Yes

Replace the thermostat.

(See THERMOSTAT REMOVAL/INSTALLATION [MZR 2.0 DISI i-stop].)

Reinstall the thermostat, then go to the next step.

(See THERMOSTAT REMOVAL/INSTALLATION [MZR 2.0 DISI i-stop].)

Access the ECT PID using the M-MDS.

(See ON-BOARD DIAGNOSTIC TEST [MZR 2.0 DISI i-stop].)

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

Go to the next step.

Inspect the ECT sensor.

(See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION [MZR 2.0 DISI i-stop].)

• If there is any malfunction:

― Replace the ECT sensor.

(See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION [MZR 2.0 DISI i-stop].)

• If there is no malfunction:

― Perform the instrument cluster symptom troubleshooting “NO. 10 LOW ENGINE COOLANT TEMPERATURE INDICATOR LIGHT/HIGH ENGINE COOLANT TEMPERATURE WARNING LIGHT ILLUMINATES OR FLASHES CONTINUOUSLY”.

(See NO. 10 LOW ENGINE COOLANT TEMPERATURE INDICATOR LIGHT/HIGH ENGINE COOLANT TEMPERATURE WARNING LIGHT ILLUMINATES OR FLASHES CONTINUOUSLY [INSTRUMENT CLUSTER].)

Verify the test results.

• If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZR 2.0 DISI i-stop].)

• If a 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, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZR 2.0 DISI i-stop].)