DME 7.2

P0506
32 Idle Air Control at Stop - Below Limit

P0507
32 Idle Air Control at Stop - Above Limit

Function
Since idling is one of the most frequent operating conditions in town traffic, it is a particularly good idea to set an idle speed which is as low as possible, with savings in fuel consumption and fewer exhaust emissions. Sensors measure the rpm, engine temperature and throttle position. Furthermore, load conditions, e.g. A/C, power steering and disturbance variables, too, can be measured or predicted. The quantity of air sucked in (charge control) and/or the ignition timing (ignition control) can be varied to control the rpm at idle. The electronic governor compares the momentary rpm with the desired (nominal) idle speed.
With the ME 7.2, idle air control is effected directly via the throttle valve.

Diagnosis conditions
- Start-up ended.
- Speed = 0 km/h
- Throttle valve in idle position
- Engine temperature > 60 °C
- Intake air temperature > -10 °C
- No fuel tank ventilation or tank ventilation diagnosis
- Altitude correction factor > 0.75
- No faults in speed signal, throttle position sensor, engine temperature, EVAP canister purge valve or tank ventilation system

A fault is detected and stored in the memory after 15 sec. if the engine speed is too high by 200 rpm or too low by 100 rpm.












NOTE: If faults are stored for the throttle jacking device, eliminate these faults first.

Diagnosis Procedure - Below Limit:

Diagnosis Procedure - Above Limit:

1 Perform adaptation.

1. Switch on the ignition.
2. Wait one minute. Do not press the accelerator.
3. Switch off the ignition for at least 10 seconds.
4. Read out the fault memory.