Test Point 11/12 - IACV open/closed winding
TEST POINT 11 and 12 - Idle stabilizer (V) - Fault codes 1_27/1_28Possible Causes, Elimination, Remarks
The idle stabilizer is designed as a twin-winding actuator with one opening winding and one closing winding.
Using the System Tester 9288, actuation of the idle stabilizer may be read directly in the Drive links menu item.
If no audible pulse is present, check the following:
Voltage supply
Connect voltmeter with disconnected plug of idle stabilizer terminal 2 and engine ground. Ignition on.
Display: Battery voltage
Configuration of terminals
Terminal 1 Closing winding signal
Terminal 2 Battery voltage
Terminal 3 Opening winding signal
No display: Check power supply in accordance with wiring diagram.
Check the control signal
Using the System Tester 9288, the idle stabilizer signal may be read directly in the Actual values menu item.
Operational check: Switch on loads in idle mode. % display must change, idle speed remains constant.
If not:
Connect 3-pin adapter lead VIN 1501 between idle stabilizer and plug port.
Connect oscilloscope to the adapter lead terminal 1 (closing winding) as well as terminal 3 (opening winding).
Make sure the wiring connectors are not shorted to vehicle ground - to avoid short circuits.
With the engine running, the following display must appear:
1. Signal (terminal 1, opening closing signal)
2. Signal (terminal 3, opening winding signal)
If no audible pulse is detected even though voltage is present and a signal is applied, replace the idle stabilizer.