Motronic M 1.5.4 Quick Check F8:ECU CONTROL
IAC CONTROL
| Conditions for Checking | Nominal Value |
Affected Terminals: 4, 24
Possible Trouble Codes: 56, 57
Engine running at idle speed
Engine throttle valve CLOSED (accelerator pedal in idle position)
SIM. IDLE POS. SW ACTIVE
Vehicle stationary
Press key F8 in the system main menu, select the desired test using the arrow keys and confirm with YES. Follow the instructions in the diagnostic tester display.
Note:
In this mode, it is possible to set the idle speed adjuster to a fixed value via the arrow keys In addition, the YES and NO keys can be used to display the various data list parameters. Key F9 is used to store the data as in the snapshot mode.
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In this control mode, the diagnostic tester specifies the position for the idle speed adjuster. Idle speed regulation is no longer performed.
This mode should be used if it appears necessary to evaluate the various engine parameters (e.g. 02 INTEGRATOR or INJECTION PULSE) at a fixed idle speed adjuster position (constant air volume) or if it is to be determined whether the idle speed adjuster runs evenly and without hesitation over its entire movement range.
If the engine is not properly warm (coolant temperature lower than 100 °C/212 °F) when this test is started or carried out, the engine speed may oscillate considerably between approx. 1300 and 2000 rpm in the upper engine speed range (approx. 1900 rpm). To prevent this, always perform this test at high engine temperatures or use the diagnostic tester arrow keys to lower the engine speed during the test to avoid the upper engine speed range.
| When this test is completed, the engine may stall. This may especially be the case if the cooling fan is running or other consumers are switched on. The snapshot data recorded by the diagnostic tester is however retained. |