DTC P0443

DTC: P0443 Evaporative emission control system purge control valve (Y58/1) circuit malfunction

Activation requirement CHECK ENGINE lamp:
Two consecutive trips with fault.

Activation of CHECK ENGINE lamp:
At start of next trip.

Test to detect fault:
The engine control module checks the Y58/1 control circuit for short circuit and open circuit. If a fault is detected, a message is sent to the diagnostic module via CAN. The diagnostic module recognizes a fault if problems occur for longer than approximately 2 seconds.

If all conditions are met, the diagnostic module activates the purge flow switchover valve (Y27/6). The diagnostic module pressure sensor (B5/2) thereby detects the pressure in the line from the charcoal canister to the purge control valve (Y58/1). The pressure pattern in the line varies correspondingly to the cycled activation of the purge control valve (Y58/1).

The diagnostic module monitors the pressure pattern for approximately 4 seconds. If the pressure values vary by less than approximately 50 mbar, a fault is recognized. At higher elevations, an barometric (altitude) correction takes place (e.g. above 2400 m pressure variations of approximately 11 mbar are permissible).