Mazda 3 Workshop Manual page 557

Mazda 3 Workshop Manual – Engine + Wiring Diagrams + Diagnostic Trouble Codes
• No air leakage from intake-air system
• No restriction of intake-air system
• Proper sealing of intake manifold and
components attached to intake manifold:
EGR valve, IAC 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 engine at part throttle.
10
Does engine run smoothly at part
throttle?
Connect the WDS or equivalent to the
DLC-2.
11 Access RPM PID.
Is RPM PID indicating engine speed
during engine cranking?
Downloaded from
Yes
No
Yes
No
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No
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DTC is displayed:
Go to the appropriate DTC inspection.
(See DTC TABLE [LF].)
Communication error message is
displayed:
Inspect for the following:
• Open circuit in wiring harness between
main relay and PCM terminal 1BE
• Open circuit in wiring harness between
main relay terminal B and PCM terminal
1AT
• The main relay is stuck open.
• Open or poor GND circuit (PCM terminal
1BH, 1AZ, 1BC, 1BD or 1BG)
• 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 [LF].)
Go to the next step.
Go to the next step.
Inspect for following:
• Open or short circuit in CKP sensor
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