Audi Workshop Service and Repair Manuals

Checking coolant temperature sender -G62- Special tools and workshop equipment required t  Portable multimeter -V.A.G 1526C- t  Adapter set -V.A.G 1594C- t  121-pin adapter cable -V.A.G 1598/31- t  Vehicle diagnosis and service information system -VAS 5052-

Overview of fitting locations → Chapter Test sequence   Note Engine cold –  Connect up the vehicle diagnostic and service information system -VAS 5052- and select the engine electronics control unit. Engine must be idling. –  Select the function “Read measured value block”. –  Select “Display group number 004”. –  Check the display in zone 3.

	Display zones
	1	2	3	4
Display Group 004: Coolant temperature with engine idling
Display	xxxx rpm	xx.x V	xxx.x °C	xxx.x °C
Display	Engine speed	Battery voltage	Coolant temperature	Intake air temperature
Operating range			-48.0...143.0 °C
Specification	xxxx rpm	12.0...15.0 V	Temperature value must increase steadily	From ambient temperature to 110 °C

If display in zone 3 is not realistic: –  Unplug the connector at the coolant temperature sender -G62-.

–  Connect up the multimeter (resistance measuring range) between contacts C and D of the sender. Area A shows the resistance values for the temperature range 0...50 °C, area B the values for the temperature range 50...100 °C.

Examples: t  30 °C corresponds to a resistance of 1500...2000 Ω t  80 °C corresponds to a resistance of 275...375 Ω If the reading does not match the specification: –  Replace the coolant temperature sender -G62-. If the reading matches the specification: –  Connect the test box -V.A.G 1598/31- to the wiring harness to the engine control unit, but do not connect the actual engine control unit → Chapter.

–  Check for open circuit and short to earth or positive in the following wiring:

Connector Contact	Test box -V.A.G 1598/31- Socket
3	108
4 (signal)	93

–  Check the two wires for mutual short circuit. –  Eliminate open circuit in wiring/short circuit if necessary. If no fault is found in the wiring: –  Replace the engine control unit → Chapter.