Audi Workshop Service and Repair Manuals

Special tools and workshop equipment required

• ◆ V.A.G 1526 A
• ◆ V.A.G 1594 A
• ◆ V.A.G 1598/31

Test requirements:

• ● Diagnosis of map-controlled engine cooling system performed .

Test sequence

• ‒ → Remove engine cover -arrows-.
• ‒ Start engine and run at idling speed.

• ‒ → Unplug 4-pin connector -1- at coolant temperature sender -G62.

Note:

Unplugging the connector from the coolant temperature sender causes the engine control unit to detect a fault in the map-controlled engine cooling system. It then constantly actuates the thermostat using full battery voltage.

• ‒ Unplug the 2-pin connector -2- from thermostat for map-controlled engine cooling system -F265.

• ‒ → Connect multimeter between contacts 1 and 2 to measure voltage.
• ‒ Specification: Approx. battery voltage (after a short waiting period)

If specification is not attained:

• ‒ Connect multimeter as follows to measure voltage:

• ‒ Specification: approx. battery voltage
• Switch ignition off.

If specification is not attained:

• ‒ Check the wiring from contact 1 of the connector to the power supply relay for Simos control unit -J363 (below cover on left of bulkhead) for open circuit using the current flow diagram.
• ‒ Eliminate open circuit or using the current flow diagram.

If specification is attained:

• ‒ → Connect the V.A.G 1598/31 test box to wiring harness connectors; the engine control unit should not be connected. Attach the earth clip of test box to earth -arrow-.

=> Simos Fuel Injection and Ignition System; Repair group 24

• ‒ → Check for open circuit in the following wiring connections:

• ‒ Eliminate open circuit using the current flow diagram.

If no wiring fault is detected:

• ‒ Check function of thermostat => Page 19-36.
• ‒ Plug in the connectors.
• ‒ Finally, interrogate and erase the engine control unit fault memory as faults are stored when the connectors are unplugged.

=> Simos Fuel Injection and Ignition System; Repair group 24