P0506

P0506
Idle Air Control - Engine speed too low

P0507
Idle Air Control - Engine speed too high

Function
The Idle Air Control (IAC) permits a stable and low idle rpm. The Idle Air Control (IAC) Valve opens a bypass to the throttle valve. The amount of the opening depends on the operation of the IAC Valve. As the Mass Air Flow (MAF) Sensor senses this additional air, the injection volume changes. The Engine Control Module (ECM) makes comparisons with the specified values of the engine speed and adjusts accordingly.

Diagnostic conditions
- Engine start-up completed
- Vehicle speed = 0 km/h
- Throttle valve at Closed Throttle Position
- Engine temperature > 90°C.
- No fault for speed signal, throttle position sensor, idle air control valve and engine temperature.

NOTE: A fault is detected and stored after 15 seconds if the speed is too high or too low by 60 1/min.





Wiring Diagram








Diagnostic procedure
Check IAC Valve.
1. Connect system tester.
2. Switch to menu point "Drive Links" and activate.
3. A distinct clicking noise must be heard.





Check air intake system for leaks.
1. Remove air cleaner cover and insert.
2. Undo hose clamp on mass airflow sensor with a cross-head screwdriver, e.g. from Messrs. With Order No. 153-1 (350 mm long).





3. The restricted space available necessitates separation of the mass air flow sensor and air cleaner housing in the engine compartment. To remove, turn the mass air flow sensor in the direction of the arrow (driving direction), at the same time countering at the air cleaner housing (bayonet lock).








4. Lever off circlip and remove protective grille.
5. Secure sealing plate 9264/1 on mass air flow sensor using screws M 4 x 40 and washers.

NOTE: Check the position of the mass air flow sensor on the sealing plate before finally tightening the screws, i.e. no light gap must be visible upon inspection.








6. Build up a pressure of approx. 0.5 bar.

NOTE:
- Large leaks are very audible when the pressure has been built up; small leaks can be made visible using leak spray.
- The pressure relief valve on the oil tank opens at 180 +/- 20 mbar. Block the valve. To do this, remove the front wheel housing liner of the right rear wheel housing. Close off the hose from the oil tank pressure relief valve with a suitable stopper.

- Remove the stopper from the hose after carrying out the leak test. Assemble the mass air flow sensor and air cleaner housing in the engine compartment before attaching the mass air flow sensor to the air intake system.