Audi Workshop Service and Repair Manuals

Notes:

• ◆ Testing sender with oval connector
  
• ◆ For testing the operation of the coolant temperature sender, see also "Reading measured value block", Display Group 01, display zone 2.
• ◆ Fitting location of coolant temperature sender
  .

• ‒ Unplug connector on coolant temperature sender.
• ‒ → Test resistance between contact 1 (earth) and contact 3 (signal) on 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 value does not match the specification, fit a new sender.

If the value does match the specification, test the wiring between the sender and the engine control unit as follows:

• ‒ Connect test box V.A.G 1598/22 to the wiring harness for the engine control unit.
  => Page 24-13
• ‒ → Test for open circuit in earth wire between contact 3 on coolant temperature sender connector and socket 67 on test box.

Specification: max. 1 ω.

• ‒ Test for open circuit in signal wire between contact 1 on coolant temperature sender connector and socket 53 on test box.

Specification: max. 1 ω.

• ‒ Test for short circuits between the two wires.

• ‒ → If values do not match specifications, rectify short circuits or open circuits in wiring between coolant temperature sender connector and control unit connector.

• ‒ If there are no short circuits or open circuits and the coolant temperature sender is OK, fit a new engine control unit.
  => Page 24-15

Testing coolant temperature sender with oval connector

Notes:

• ◆ For testing the operation of the coolant temperature sender, see also "Reading measured value block", Display Group 01, display zone 2.
• ◆ Fitting location of coolant temperature sender
  => Page 24-5.

• ‒ Unplug connector from coolant temperature sender.

• ‒ → Connect multimeter (resistance test range)between contacts 3 and 4 on 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°Ccorresponds to a resistance from275...375ω

If the value does not match the specification:

• ‒ Renew coolant temperature sender

• ‒ Connect testbox V.A.G 1598/22 to wiring harness for engine control unit.

• ‒ → Test the following wiring connections for open circuit and short circuit to earth or positive:

• ‒ Test for short circuits between the two wires.
• ‒ Repair open circuit or short circuit in wiring as required.

If wiring is OK:

• ‒ Renew engine control unit.