Engine Control System Operation Inspection - Mazda 6 2002 Workshop Manual

ENGINE CONTROL SYSTEM OPERATION INSPECTION

Main Relay Operation Inspection
1. Verify that the main relay clicks when the ignition switch is turned to ON position and off.
• If there is no operation sound, inspect the following.
— Main relay (See
— Harness and connector between ignition switch and main relay terminal A.
— Harness and connector between PCM terminal 2X and main relay terminal E.
Intake Manifold Vacuum Inspection
1. Verify air intake hoses are installed properly.
2. Start the engine and run it at idle.
3. Disconnect the vacuum hose between the intake manifold and purge solenoid valve from the intake manifold
side.
4. Connect a vacuum gauge to the intake manifold and measure the intake manifold vacuum.
• If not as specified, inspect the following.
Specification
More than 60 kPa {450 mmHg, 18 inHg}
Note
• Air suction can be located by engine speed change when lubricant is sprayed on the area where suction is
occurring.
— Air suction at throttle body, intake manifold and PCV valve installation points
— Accelerator cable free play
— Fuel injector insulator
— Engine compression
(See B–9 COMPRESSION
Idle Air Control System Inspection
Engine coolant temperature compensation inspection
1. Connect WDS or equivalent to the DLC-2.
2. Select 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 harness
(See F–53 ENGINE COOLANT TEMPERATURE (ECT) SENSOR
— IAC valve and related harness
(See F–13 IDLE AIR CONTROL (IAC) VALVE
Load compensation inspection
1. Start the engine and run is at idle.
2. Connect WDS or equivalent to the DLC-2.
3. Verify that P0506, P0507 or P0511 not displayed.
• If P0506, P0507 or P0511 shown, carry out DTC inspection.
(See F–67 DTC TABLE.)
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 between IAC valve connector terminals and PCM connector terminals 4G and 4J
6. Select the following PIDs.
• ACSW
• IAC
• PSP
• RPM
Note
• Ecludes temporary idle speed drop just after the loads are turned on.
TROUBLESHOOTING
T–24 RELAY INSPECTION.)
INSPECTION.)
INSPECTION.)
INSPECTION.)
A6E398018881W32
F
F–229