Mazda 3 Workshop Manual page 458

Mazda 3 Workshop Manual – Engine + Wiring Diagrams + Diagnostic Trouble Codes
Verify the following:
• Vacuum connection
• Air cleaner element
• No air leakage from intake-air system
• No restriction of intake-air system
• Proper sealing of intake manifold and
components attached to intake manifold:
8
IAC valve, EGR valve
• Ignition wiring
• Fuel quality: proper octane,
contamination, winter/summer blend
• Electrical connections
• Smooth operation of throttle valve
Are all items normal?
Connect the WDS or equivalent to the
DLC-2.
Retrieve any continuous memory, KOEO
and KOER DTCs using WDS or
9
equivalent.
If the engine stalls, retrieve continuous
memory and KOEO DTCs.
Are there any DTCs displayed?
Attempt to start the engine at part
throttle.
10
Does the engine run smoothly at part
throttle?
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Go to the next step.
Service if necessary.
Repeat Step 8.
DTC is displayed:
Go to the appropriate DTC inspection.
(See DTC TABLE [Z6].)
Communication error message is
displayed:
Inspect for the following:
• Open circuit in wiring harness between
main relay and PCM terminal 1BF, or 1BG
(ATX)
• Open circuit in wiring harness between
main relay terminal B and PCM terminal
1AW.
• The main relay is stuck open.
• Open or poor GND circuit (PCM terminal
2BH, 2AZ or 2BD)
• Poor connection of vehicle body GND
No DTC is displayed:
Go to the next step.
Inspect the IAC valve and wiring harness.
(See IDLE AIR CONTROL (IAC) VALVE
INSPECTION [Z6].)
Go to the next step.
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