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

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

Test requirements:

• ● Engine cold

Test sequence

• ‒ Connect vehicle diagnostic, testing and information system VAS 5051 and select vehicle system "01 -Engine electronics" in the selection. For this purpose, the engine must be running at idling speed.

→ Display on VAS 5051:

• ‒ Under -1- select the diagnostic function "08 - Read measured value block".

→ Display on VAS 5051:

•     1 -    Enter display group
  max. input value = 255

• ‒ Enter "004" for "display group number 004" in zone -2- and confirm the entry by pressing the Q key.

→ Display on VAS 5051:

• ‒ Check coolant temperature sender in display zone -3-.

• ‒ Exit the function "08 - Read measured value block" by pressing the ◂ key.

If display zone 3 shows an implausible value:

• ‒ Disconnect connector on coolant temperature sender.

• ‒ → Connect multimeter between contacts C and D of sender to measure resistance.

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

→ Sample readings:

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

If specified value is not attained:

• ‒ Replace coolant temperature sender.

If specified value is attained:

• ‒ Connect test box V.A.G 1598/31 to wiring harness for engine control unit; do not connect the engine control unit => Page 24-19.

• ‒ → Check 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 wiring fault is detected:

• ‒ Replace engine control unit => Page 24-32.