Audi Workshop Service and Repair Manuals

Checking actuation of power output stages

• ‒ Disconnect the connectors from the power output stage.
• ‒ Disconnect the connectors from all the injectors.

• ‒ → Connect the diode lamp in turn between contacts 1, 2, 4 and 5 of the 5-pin connector and engine ground and operate the starter for a few seconds in each case. The diode test lamp should flash each time.

• ‒ If the diode test lamp does not flash, connect test box V.A.G1598/19 to the wiring harness for Motronic control unit -J220.
• ‒ → Test wiring from 5-pin connector at output stage ...

• ‒ → ... to Motronic control unit -J220 for open circuit and short to positive or ground according to current flow diagram.

• ‒ → If the wiring to the Motronic control unit is OK, check ground wire from contact 3 of both 5-pin connectors to engine ground for continuity.
• ‒ If no faults are present in any of the wiring and the diode lamp has not flashed, renew the Motronic control unit.

Testing function of output stage

• ‒ Connect 5-pin connector at output stage.
• ‒ Connect a diode lamp between battery positive and one each of the contacts at the 4-pin output of the output stage and operate the starter for a few seconds in each case.
  The diode test lamp should flash each time.
• ‒ If the diode test lamp does not flash in the case of one or several outputs, replace the power output stage.

Note:

Diode test lamps with very low current consumption already glow when the engine is not running and become brighter and darker during starting.