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
• ◆ VAS 5051 with VAS 5051/1

or

• ◆ V.A.G 1551 with V.A.G 1551/3 A

Fitting location => Fitting locations overview, Page 24-5

Test requirement:

• ● Engine cold

Test sequence

• ‒ Connect vehicle diagnostic, testing and information system VAS 5051 (or fault reader V.A.G 1551). Select engine electronics control unit by entering the address word "01" ; when doing this the engine must be running at idling speed.

• ‒ Enter "08" to select the function "Read measured value block" and confirm entry with Q key.

• ‒ Enter "004" to select Display Group 004 and confirm entry with Q key.

• ‒ Check display in display zone 3.

If display zone 3 shows an implausible value:

• ‒ Unplug connector on coolant temperature sender.
• ‒ → Connect multimeter (resistance measurement range) between contacts 1 and 3 on the sender.

Scale A shows resistance values for temperature range 0...50 °C and scale B the values for temperature range 50...100 °C.

→ Examples:

• ◆ 30 °C corresponds to a resistance from 1500...2000 ω
• ◆ 80 °C corresponds to a resistance from 275...375 ω

If the specification is not attained:

• ‒ Fit a new coolant temperature sender.

If the specification is obtained:

• ‒ Connect test box V.A.G 1598/31 to wiring harness for engine control unit. Do not connect to the engine control unit itself.
  => Page 24-20.
• ‒ → Test for open circuit and short to positive or earth in the following wiring connections:

• ‒ Test for short circuits between the two wires.
• ‒ Rectify any open/short circuit as necessary.

If no fault is detected in the wiring:

• ‒ Fit a new engine control unit => Page 24-24.