Mazda 3 Workshop Manual page 569

Mazda 3 Workshop Manual – Engine + Wiring Diagrams + Diagnostic Trouble Codes
Diagnostic procedure
STEP INSPECTION
Warm up the engine.
1 Idle the engine for 5 min.
Is the symptom disappeared?
Verify following:
• External fuel shut off or accessory
(such as kill switch, alarm)
• Fuel quality (such as proper octane,
contamination, winter/summer blend)
• No air leakage from intake-air system
• Proper sealing of intake manifold and
components attached to intake
manifold: EGR valve, IAC valve
2
• Ignition wiring
• Electrical connections
• Fuses
• Smooth operation of throttle valve
• PCM GND circuit (PCM terminal 1AZ,
1BC, 1BD, 1BG and/or 1BH)
Are all items normal?
Connect the WDS or equivalent to the
DLC-2.
Retrieve any continuous memory,
3
KOEO and KOER using WDS or
equivalent.
Are there any DTCs displayed?
4 Is the engine overheating?
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Caution
• Disconnecting/connecting quick release connector without cleaning it may
possibly cause damage to fuel pipe and quick release connector. Always clean
quick release connector joint area before disconnecting/connecting, and make
sure that it is free of foreign material.
RESULTS
Yes
No
Yes
No
Yes
No
Yes
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ACTION
Troubleshooting completed. (Cause of this
symptom is that the idle learning of IAC
system is not completed.)
Go to the next step.
Go to the next step.
Service if necessary.
Repeat Step 2.
DTC is displayed:
Go to the appropriate DTC inspection.
(See DTC TABLE [LF].)
No DTC is displayed:
Go to the next step.
Go to symptom troubleshooting "No.17
Cooling system concerns - Overheating".
(See NO.17 COOLING SYSTEM
CONCERNS-OVERHEATING
- automotive repair manuals website
[LF].)