Test Point 20 - Tank ventilation valve
TEST POINT 20 - Tank ventilation valve (V) - Fault code 1_43Possible Causes, Elimination, Remarks
When the engine operates at operating temperature, the tank ventilation valve is opened for a longer or shorter period as a function of the load. The opening period is determined by a ground pulse from the control unit.
Activation test
To activate the tank ventilation valve directly, System Tester 9288 may be used, selecting the Drive links menu item.
If there is no audible pulse from the tank venting valve, check voltage supply at the terminal of the tank ventilation valve plug and body ground according to the wiring diagram.
Ignition on.
Display: Battery voltage
Control signal test
Connect DME test lead (Bosch No. 1 684 463 093) between tank ventilation valve and plug connection. Connect and adjust engine tester according to manufacturer's instructions.
The tank ventilation valve is not activated permanently.
Testing must be performed within 7 minutes after starting the engine at operating temperature. Then interrupt activation of ventilation valve for approx. 75 seconds, continue afterwards.
Start engine and accelerate. With the engine at operating temperature, the following display must be visible on the tester:
The signal becomes wider as the air throughput increases.
If there is no signal, check path in accordance with wiring diagram.