Mazda CX-9 Grand Touring 2009 Manual page 1364

POSSIBLE CAUSE
DIAGNOSTIC PROCEDURE
NO.18 COOLING SYSTEM CONCERNS-RUNS COLD (MZI-3.7) DIAGNOSTIC PROCEDURE
STEP INSPECTION
Is customer complaint "Lack of passenger
1
compartment heat" only?
Does the engine speed continue at fast
2
idle?
Remove the thermostat and inspect
operation.
(See THERMOSTAT
REMOVAL/INSTALLATION [MZI-
3
3.7] .)
(See THERMOSTAT INSPECTION
[MZI-3.7] .)
Is thermostat normal?
Inspect cooling fan control system
operation.
(See ENGINE CONTROL SYSTEM
4 OPERATION INSPECTION [MZI-
3.7].)
Does the cooling fan control system
function properly?
Verify test results.
If normal, return to diagnostic index to service any additional symptoms.
(See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7].)
5
If malfunction remains, inspect related Service Bulletins and/or On-line Repair
Information and perform repair or diagnosis.
2008 Mazda CX-9 Grand Touring
2008 ENGINE Symptom Troubleshooting (MZI-3.7) - Mazda CX-9
Thermostat malfunction
Cooling fan system malfunction
If vehicle is repaired, troubleshooting completed.
If vehicle is not repaired or additional diagnostic information is not available,
replace PCM.
RESULTS
Yes Inspect A/C and heater system.
No Go to the next step.
Go to symptom troubleshooting "No.9 Fast
idle/runs on".
Yes
(See NO.9 FAST IDLE/RUNS ON [MZI-
3.7].)
No Go to the next step.
Yes Go to the next step.
No Replace the thermostat.
Access ECT PID.
Inspect for both ECT PID and temperature
gauge on instrument cluster readings.
If the temperature gauge on the instrument
cluster indicates normal range but ECT PID
Yes is not the same as temperature gauge
reading, inspect the CHT sensor.
If the temperature gauge on the instrument
cluster indicates cold range but ECT PID is
normal, inspect the temperature gauge and
heat gauge unit.
No Repair or replace the malfunctioning part.
ACTION