DIAGNOSTIC PROCEDURE
NO.18 COOLING SYSTEM CONCERNS-RUNS COLD (MZI-3.7) DIAGNOSTIC PROCEDURE
POSSIBLE CAUSE
z
Thermostat malfunction
z
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 the next step.
2
Does the engine speed continue at fast
idle?
Yes
Go to symptom troubleshooting "No.9 Fast
idle/runs on".
(See
NO.9 FAST IDLE/RUNS ON [MZI-
3.7]
.)
No
Go to the next step.
3
Remove the thermostat and inspect
operation.
(See
THERMOSTAT
REMOVAL/INSTALLATION [MZI-
3.7]
.)
(See
THERMOSTAT INSPECTION
[MZI-3.7]
.)
Is thermostat normal?
Yes
Go to the next step.
No
Replace the thermostat.
4
Inspect cooling fan control system
operation.
(See
ENGINE CONTROL SYSTEM
OPERATION INSPECTION [MZI-
3.7]
.)
Does the cooling fan control system
function properly?
Yes
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
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.
5
z
Verify test results.
{
If normal, return to diagnostic index to service any additional symptoms.
(See
SYMPTOM DIAGNOSTIC INDEX [MZI-3.7]
.)
{
If malfunction remains, inspect related Service Bulletins and/or On-line Repair
Information and perform repair or diagnosis.
z
If vehicle is repaired, troubleshooting completed.
z
If vehicle is not repaired or additional diagnostic information is not available,
replace PCM.
2008 Mazda CX-9 Grand Touring
2008 ENGINE Symptom Troubleshooting (MZI-3.7) - Mazda CX-9
Microsoft
Sunday, November 15, 2009 10:10:05 AM
Page 73
© 2005 Mitchell Repair Information Company, LLC.
