SAAB WIS ONLINE

DTC P0509 IDLE CONTROL SYSTEM CIRCUIT HIGH

DTC P0509 IDLE CONTROL SYSTEM CIRCUIT HIGH

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


(1)

Engine control module (ECM)

(2)

Detecting circuit

(3)

Battery voltage

(4)

Main relay

(5)

Idle air control solenoid valve



ENABLE CONDITION

Secondary Parameters Enable Conditions
After engine starting

1 second or more

Idle air control solenoid valve duty ratio

5 — 95%

Battery voltage

≥ 10.9 V



GENERAL DRIVING CYCLE

Perform the diagnosis after starting the engine.

DIAGNOSTIC METHOD

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

Judgment Value

Malfunction Criteria Threshold Value
Number of change that idle air control solenoid valve signal during 64 milliseconds

≥ 225

(160 at normal since the cycle is 4 milliseconds)



Time Needed for Diagnosis: 64 milliseconds

Malfunction Indicator Light Illumination: Illuminates as soon as malfunction occurs.

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)