P0508

DTC P0508 - IDLE CONTROL SYSTEM CIRCUIT LOW

OUTLINE OF DIAGNOSIS
Detect open or short circuit in idle air control solenoid valve.
Period of idle air control solenoid valve is 4 milliseconds and it is too short.
Judge OK/NG in accordance with the number of change of OFF to ON signal.




COMPONENT DESCRIPTION




ENABLE CONDITION

GENERAL DRIVING CYCLE
Perform the diagnosis after starting the engine.

DIAGNOSTIC METHOD




Judge NG when the malfunction criteria are completed. Judge OK and clear NG when the malfunction criteria are not completed.

DTC CLEAR CONDITION
- When the OK idling cycle was completed 40 times in a row
- When " Clear Memory " was performed

MALFUNCTION INDICATOR LIGHT CLEAR CONDITION
- When the OK driving cycle was completed 3 times in a row
- When " Clear Memory " was performed

FAIL SAFE
- Idle air control solenoid valve feedback correction: Not allowed to calculate ifb (idle air control solenoid valve feedback amount)
- Fuel shut-off: Shut-off fuel for only #1 and #2 cylinder, or for all cylinder in accordance with vehicle speed, engine speed, throttle position
- Judgment of heavy fuel: Not allowed to make the judgment of heavy fuel

ECM OPERATION AT DTC SETTING
Memorize the freeze frame data. (For test mode $02)