Mazda 3 - Idle Air Control System Inspection; Engine Coolant Temperature Compensation Inspection; Load Compensation Inspection

Mazda 3 Workshop Manual – Engine + Wiring Diagrams + Diagnostic Trouble Codes
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- Fuel injector insulator
- Engine compression (See COMPRESSION INSPECTION [Z6].)
Idle Air Control System Inspection
Engine coolant temperature compensation inspection
1. Connect the WDS or equivalent to the DLC-2.
2. Access the following PIDs.
• ECT
• IAT
• RPM
3. Verify that the engine is in cold condition, then start the engine.
4. Verify that the engine speed decreases as the engine warms up.
• If the engine speed does not decrease or decreases slowly, inspect the following.
- ECT sensor and related wiring harness (See ENGINE COOLANT TEMPERATURE (ECT)
SENSOR INSPECTION [Z6].)
- IAC valve and related wiring harness (See IDLE AIR CONTROL (IAC) VALVE INSPECTION
[Z6].)
Load compensation inspection
1. Start the engine and run is during idle.
2. Connect the WDS or equivalent to the DLC-2.
3. Verify that P0511 not displayed.
• If P0511 shown, perform the DTC inspection. (See DTC P0511 [Z6].)
4. Change the duty value of the IAC valve to 100% using the IAC PID.
5. Verify that the idle speed increases.
• If the idle speed does not change, inspect the following.
- IAC valve air passage
- Open or short circuit in wiring harness between IAC valve terminals and PCM terminals 2X and
2AB
6. Access the following PIDs.
• AC_REQ
• IAC
• PSP
• RPM
Note