Mazda 6 2002, Workshop Manual

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F–216
TROUBLESHOOTING
End Of Sie
NO.18 COOLING SYSTEM CONCERNS-RUNS COLD
A6E398018881W20
Diagnostic procedure
End Of Sie
9 Cool down the engine.
Remove thermostat and inspect operation.
(See
E–7 THERMOSTAT REMOVAL/
INSTALLATION .)
(See E–8 THERMOSTAT INSPECTION .)
Is thermostat okay?
Yes Engine coolant temperature and thermostat are okay,
inspect engine block for leakage or blockage.
No Access ECT PID.
Inspect for both ECT PID and temperature gauge
readings.
If temperature gauge on instrument cluster indicates
normal range but ECT PID is not same as temperature
gauge reading, inspect ECT sensor.
If temperature gauge on instrument cluster indicates
overheating but ECT PID is normal, inspect
temperature gauge and heat gauge unit.
10 Verify test results.
•
If okay, return to diagnostic index to service any additional symptoms.
•
If malfunction remains, replace PCM.
STEP INSPECTION RESULTS ACTION
18 COOLING SYSTEM CONCERNS -RUNS COLD
DESCRIPTION Engine takes excessive period for reaching normal operating temperature.
POSSIBLE CAUSE
•
Thermostat malfunction
•
Condenser fan system malfunction
•
Cooling fan system malfunction
STEP INSPECTION RESULTS ACTION
1 Is customer complaint "Lack of passenger
compartment heat" only? Yes Inspect A/C and heater system.
No Go to next step.
2 Does engine speed continue at fast idle? Yes Go to symptom troubleshooting "No.9 Fast idle/runs
on".
No Go to next step.
3 Remove thermostat and inspect operation.
(See
E–7 THERMOSTAT REMOVAL/
INSTALLATION .)
(See E–8 THERMOSTAT INSPECTION .)
Is thermostat okay?
Yes Go to next step.
No Replace thermostat.
4 Inspect cooling fan control system operation.
(See
F–234 Cooling Fan Control System
Inspection .)
Does cooling fan control system work properly?
Yes Access ECT PID.
Inspect for both ECT PID and temperature gauge on
instrment cluster readings.
If temperature gauge on instrument cluster indicates
normal range but ECT PID is not same as temperature
gauge reading, inspect ECT sensor.
If temperature gauge on instrument cluster indicates
cold range but ECT PID is normal, inspect temperature
gauge and heat gauge unit.
No Repair or replace malfunctioning part.
5 Verify test results.
•
If okay, return to diagnostic index to service any additional symptoms.
•
If malfunction remains, replace PCM.