NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [MZ-CD 1.6 (Y6)]

id0103b3802300

17

COOLING SYSTEM CONCERNS-OVERHEATING

DESCRIPTION

•  The engine runs at higher than normal temperature/overheats.

POSSIBLE CAUSE

•  Cooling fan malfunction

•  Low drive belt tension

•  Drive belt damage

•  Improper coolant level

•  Thermostat malfunction

•  Radiator clogging

•  Improper water/anti-freeze mixture

•  Improper or damaged radiator cap

•  Radiator hose damage

•  Coolant leakage (engine internal, turbocharger, external)

•  A/C system malfunction

•  EGR system malfunction

17	COOLING SYSTEM CONCERNS-OVERHEATING
DESCRIPTION	• The engine runs at higher than normal temperature/overheats.
POSSIBLE CAUSE	• Cooling fan malfunction • Low drive belt tension • Drive belt damage • Improper coolant level • Thermostat malfunction • Radiator clogging • Improper water/anti-freeze mixture • Improper or damaged radiator cap • Radiator hose damage • Coolant leakage (engine internal, turbocharger, external) • A/C system malfunction • EGR system malfunction

Diagnostic Procedure

STEP	INSPECTION	RESULTS	ACTION
1	Inspect the following: • Engine coolant level • Coolant leakage (around heater unit in passenger compartment, coolant hoses and/or radiator, and around coolant heater unit.) • Water and anti-freeze mixture • Radiator condition • Collapsed or restricted radiator hoses • Radiator pressure cap • Drive belt tension • Drive belt • Fan rotational direction Are all items normal?	Yes	Go to the next step.
1		No	Service if necessary. Repeat Step 1.
2	Perform the self-test function using the M-MDS. Turn the engine switch to the ON position. Retrieve any DTC. Are DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC test. Communication error message is displayed: Inspect for the following: • Open circuit between PCM control relay and PCM terminal 236 or 231 • Open circuit between PCM control relay and PCM terminal 241 • PCM control relay stuck open • Open or poor ground circuit (PCM terminal 307, 308 or 332) • Poorly connected vehicle body ground
2		No	No DTC is displayed: Go to the next step.
3	Примечание • The following test should be performed on vehicles with A/C system. Go to the next step for vehicles without A/C system Start the engine and run it at idle speed. Turn the A/C switch off. Is the A/C compressor disengaged?	Yes	Go to the next step.
3		No	Go to symptom troubleshooting “NO.24 A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY”.
4	Inspect the cooling fan system operation. Is the cooling fan system operation normal?	Yes	Go to the next step.
4		No	Repair or replace malfunctioning part according to the cooling fan system operation results.
5	Is the drive belt normal?	Yes	Go to the next step.
5	Is the drive belt normal?	No	Replace the drive belt.
6	Perform the EGR system inspection. Is the EGR system normal?	Yes	Go to the next step.
6		No	Repair or replace malfunctioning part according to the EGR system operation results.
7	Cool down the engine. Remove the thermostat and inspect the operation. Is the thermostat normal?	Yes	The thermostat is normal. Inspect the cylinder block for leakage or blockage.
7		No	Replace the thermostat.
8	Verify test results. • If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZ-CD 1.6 (Y6)].) • If the malfunction remains, inspect related Service 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, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZ-CD 1.6 (Y6)].)