4
VERIFY CURRENT INPUT SIGNAL STATUS
(KEY TO ON/IDLE)
z
Access APP1, APP2, APP3, ECT, IAT, MAF,
RPM TP_REL and VSS PIDs using the M-
MDS. (See
PCM INSPECTION [MZI-
3.7]
.)
z
Is there any signal that is far out of
specification when the ignition switch is in
the ON position and the engine runs at idle?
Yes
Inspect the suspected circuit or part or
both according to inspection results.
Then go to Step 13. (See
PCM
INSPECTION [MZI-3.7]
.)
No
Go to the next step.
5
VERIFY CURRENT INPUT SIGNAL STATUS
UNDER TROUBLE CONDITION
z
Inspect the same PIDs as in Step 4 when
simulating the FREEZE FRAME DATA
condition.
z
Is there any signal which causes drastic
changes?
Yes
Inspect the suspected circuit or part or
both according inspection results. Then
go to Step 13. (See
PCM INSPECTION
[MZI-3.7]
.)
No
Go to the next step.
6
INSPECT SPARK PLUG CONDITION
z
Turn the ignition switch off.
z
Remove the spark plug from the suspected
cylinder.
z
Check the spark plug condition:
{
Cracks
{
Excess wear
{
Gap
{
Wet
z
Is any problem found on the spark plug?
Yes
z
If the spark plug is wet, fuel
flooding is suspected. Go to Step
9.
z
If the spark plug has a crack,
excess wear or improper gap,
replace the malfunctioning spark
plug. Then go to Step 13.
(See
CRUISE CONTROL
SWITCH INSPECTION [MZI-
3.7]
.)
No
Go to the next step.
7
INSPECT IGNITION SYSTEM OPERATION
FOR SUSPECTED CYLINDER
z
Perform the spark test for the suspected
cylinder. (See
ENGINE CONTROL
SYSTEM OPERATION INSPECTION
[MZI-3.7]
.)
z
Are the results of the spark test normal?
Yes Go to the next step.
No
Replace or replace the malfunctioning
part according to the spark test results,
then go to Step 13.
8
INSPECT FUEL INJECTOR WIRING
HARNESS
z
Remove the intake air system parts.
z
Disconnect the fuel injector connector on the
suspected cylinder.
Yes Go to the next step.
Inspect the fuel injector wiring harnesses.
2008 Mazda CX-9 Grand Touring
2008 ENGINE PERFORMANCE On-Board Diagnostic (MZI-3.7) - Mazda CX-9
Microsoft
Sunday, November 15, 2009 10:08:36 AM
Page 158
© 2005 Mitchell Repair Information Company, LLC.