18

COOLING SYSTEM CONCERNS-RUNS COLD

DESCRIPTION

• Engine does not reach normal operating temperature.

POSSIBLE CAUSE

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

• ECT sensor No.1 malfunction

• Instrument cluster malfunction

• Cooling fan system malfunction

• Condenser fan system malfunction

• Thermostat malfunction

• Foreign matter penetration in engine coolant

Item (definition)

Unit/Condition

Definition

Condition/Specification (Reference)

ECT

°C, °F

Engine coolant temperature (No.1)

• Displays ECT

V

• ECT is 20 °C {68 °F}: Approx. 3.10 V

• ECT is 40 °C {104 °F}: Approx. 2.16 V

• ECT is 60 °C {140 °F}: Approx. 1.40 V

• ECT is 80 °C {176 °F}: Approx. 0.87 V

• ECT is 100 °C {212 °F}: Approx. 0.54 V

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 [SKYACTIV-G 2.5].)

No

Go to the next step.

3

• Access the ECT PID using the M-MDS.

  (See ON-BOARD DIAGNOSTIC TEST [SKYACTIV-G 2.5].)

• 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 No.1.

(See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION [SKYACTIV-G 2.5].)

• If there is any malfunction:

• Replace the ECT sensor No.1.

  (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)

• If there is no malfunction:

• Perform the instrument cluster symptom troubleshooting “LOW ENGINE COOLANT TEMPERATURE INDICATOR LIGHT/HIGH ENGINE COOLANT TEMPERATURE WARNING LIGHT ILLUMINATES OR FLASHES CONTINUOUSLY”.

  (See LOW ENGINE COOLANT TEMPERATURE INDICATOR LIGHT/HIGH ENGINE COOLANT TEMPERATURE WARNING LIGHT ILLUMINATES OR FLASHES CONTINUOUSLY [INSTRUMENT CLUSTER].)

4

• Perform the Cooling Fan Control System Inspection.

  (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [SKYACTIV-G 2.5].)

• 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.

5

• Cool down the engine.

• Remove the thermostat.

  (See THERMOSTAT REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)

• Inspect the thermostat operation.

  (See THERMOSTAT INSPECTION [SKYACTIV-G 2.5].)

• Is there any malfunction?

Yes

Replace the thermostat.

(See THERMOSTAT REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)

No

Reinstall the thermostat, then go to the next step.

(See THERMOSTAT REMOVAL/INSTALLATION [SKYACTIV-G 2.5].)

6

• Drain the engine coolant.

  (See ENGINE COOLANT REPLACEMENT [SKYACTIV-G 2.5].)

• Has foreign matter penetrated the engine coolant?

Yes

Replace the engine coolant.

(See ENGINE COOLANT REPLACEMENT [SKYACTIV-G 2.5].)

No

Go to the next step.

7

Verify the test results.

• If normal, return to the diagnostic index to service any additional symptoms.

  (See SYMPTOM DIAGNOSTIC INDEX [SKYACTIV-G 2.5].)

• If the malfunction remains, inspect the related Service Bulletins and/or On-line Repair Information and perform 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.