P0505

DTC P0505:

DIAGNOSTIC TROUBLE CODE PO5O5
IDLE AIR CONTROL VALVE, MALFUNCTIONING

Symptom of fault
Low, high or unsteady idling speed
Idling speed sensitive to changes in load

Conditions.
The throttle position sensor indicates idling
The engine speed is more than 1200 rpm or less than 700 rpm
Normal idling speed cannot be achieved

Diagnostic procedure
1. Check whether air leakage occurs as follows:

- Start the engine and run it at idling speed.
- Restrict the air flow through the idle air control valve by clamping the air hose with grips.

The idling speed must drop sharply.

- If the idling speed is reduced, continue with step 2.
- If the idling speed is not reduced, continue fault diagnosis by checking the following:
^ Air leakage (after the throttle)
^ Incorrectly adjusted throttle
^ Faulty brake servo
^ Purge valve has stuck in the open position

DTC P0505:

2. Switch OFF the engine.

- Ignition switched ON.
- Unplug the connector of the idle air control valve.
- Connect the test lamp to the idle air control valve (female connector).
- Connect the ISAT scan tool.
- Select "IAC VALVE" on the "ACTIVATE" menu.

The test lamp is activated for 10 seconds, during which it must shine with a steady glow.

- If the test lamp does not comes on, continue with step 3.
- If the test lamp does not come on, continue with step 5.

3. Check the continuity between the idle air control valve and the ECM.

- Measure resistance between the female connector of the idle air control valve, pin 1 and safe grounding point on the engine.
- Read the resistance value after the ignition has been turned ON and then switched OFF.

The resistance value must be 5-15 Ohms.

- If the resistance value is correct, the fault is located in the lead between pin 2 and crimped connection J67.
- If the resistance value is incorrect, continue with step 4.

DTC P0505:

4. Check the lead between pin 1 and pin 49 of the ECM for shorting and discontinuity.

- If the lead is OK, continue at "Procedure before replacing ECM".

5. Measure the resistance of the idle air control valve.
The nominal resistance is 7.7 ± 1 Ohms.

- If the resistance value is incorrect, install a new valve.
- If the resistance value is correct, continue with step 6.

6. Unplug the valve's air hoses.

- Connect the electrical connector of the idle air control valve.
- Select "IAC VALVE" on the ISAT menu "ACTIVATE".

Activation takes place for 10 seconds. If a longer activation time is required, the command must be repeated.

- Check visually that the slide turns without a tendency to seize.
- If the slide seizes or sticks, install a new idle air control valve.
- If the idle air control valve operates normally, continue with step 7.

7. Erase the diagnostic trouble code and drive the car to see whether the DTC is generated again.

- If the diagnostic trouble code is registered, continue at "Procedure before replacing ECM".
- If the diagnostic trouble code is not registered, the action taken is correct. Otherwise the fault is intermittent in nature.