Mazda CX-7 2007 Workshop Manual page 162

Diagnostic procedure
STEP
1 VERIFY FREEZE FRAME DATA AND
DIAGNOSTIC MONITORING TEST RESULTS
HAVE BEEN RECORDED
• Have the FREEZE FRAME DATA and
DIAGNOSTIC MONITORING TEST RESULTS
(Misfire related) been recorded?
2 VERIFY RELATED REPAIR INFORMATION
AVAILABILITY
• Verify related Service Bulletins and/or on-line
repair information availability.
• Is any related repair information available?
3 VERIFY RELATED PENDING CODE OR
STORED DTCs
• Turn the ignition switch off then to the ON
position (Engine off).
• Verify related pending code or stored DTCs.
• Are other DTCs present?
4 VERIFY CURRENT INPUT SIGNAL STATUS
(KEY TO ON /IDLE)
• Access APP1, APP2, ECT, IAT, MAF, RPM, TP
and VSS PIDs using the M-MDS.
(See01-40-6 PCM INSPECTION[L3 WITH
TC].)
• Is there any signal that is far out of specification
when the ignition switch is turned to the ON
position and the engine idles?
5 VERIFY CURRENT INPUT SIGNAL STATUS
UNDER TROUBLE CONDITION
• Inspect the same PIDs as in Step 4 while
simulating the FREEZE FRAME DATA
condition.
• Is there any signal which causes drastic
changes?
6 INSPECT SPARK PLUG CONDITION
• Turn the ignition switch off.
• Remove the spark plug from the suspected
cylinder.
• Inspect the spark plug condition:
— Cracks
— Excess wear
— Gap
— Wetness
• Is there any problem found on the spark plug?
7 INSPECT INTAKE-AIR SYSTEM FOR AIR
SUCTION
• Inspect for air leakage at the following:
— Around connection of dynamic chamber and
intake manifold
— Around connection of intake manifold and
cylinder head
• Is air leakage found?
8 INSPECT SEALING OF ENGINE COOLANT
PASSAGE
• Perform "ENGINE COOLANT LEAKAGE
INSPECTION."
(See01-12-6 ENGINE COOLANT LEAKAGE
INSPECTION[L3 WITH TC].)
• Is there any malfunction?
01-02–120
ON-BOARD DIAGNOSTIC [L3 WITH TC]
INSPECTION
Yes Go to the next step.
No Record the FREEZE FRAME DATA and DIAGNOSTIC
MONITORING TEST RESULTS on the repair order, then
go to the next step.
Yes Perform repair or diagnosis according to the available
repair information.
• If the vehicle is not repaired, go to the next step.
No Go to the next step.
Yes Go to the appropriate DTC troubleshooting.
(See01-02-13 DTC TABLE[L3 WITH TC].)
No Go to the next step.
Yes Inspect the suspected circuit and/or part according to
inspection results. Then go to Step 14.
(See01-40-6 PCM INSPECTION[L3 WITH TC].)
No Go to the next step.
Yes Inspect the suspected circuit and/or part according to
inspection results. Then go to Step 14.
(See01-40-6 PCM INSPECTION[L3 WITH TC].)
No Go to the next step.
• If a spark plug is wet, fuel flooding is suspected. Then
Yes
go to Step 14.
• If a spark plug has cracks, excessive wear or an
improper gap, replace the malfunctioning spark plug.
Then go to Step 14.
No Go to the next step.
Yes Repair or replace suspected part, then go to Step 14.
No Go to the next step.
Yes Repair or replace the malfunctioning part according to the
inspection results.
Then go to Step 14.
No Go to the next step.
ACTION