Testing coolant temperature sender -G62 — AUDI

APZ ARJ ARN
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" => Page
01-3
.); when doing this, the engine must be running at idling speed.

Rapid data transfer
HELP
Select function XX
Indicated on display:

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

Read measured value block
Q
Enter display group number XXX
Indicated on display:

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

Read measured value block 4
⇒
1
2
3
4
Indicated on display:

Check display in display 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
Indicates · Engine speed · Battery voltage · Coolant temperature · Intake air temperature
Range · 0 ... 6800 rpm · 10.0 ... 15.0 V · -48.0 ... 143.0 °C · -48.0 ... 143.0 °C
Specification · xxxx rpm · 12.0...15.0 V · Temperature should rise steadily · Between ambient temperature and 120 °C

If display zone 3 shows an implausible value:

Note:

For access to coolant temperature sender, remove air intake hose between air mass meter and intake silencer.

Unplug connector on coolant temperature sender.

Coolant temperature sender with square plug:

Connect multimeter (resistance test range) between contacts 1 and 3 on the sender.

Coolant temperature sender with oval plug:

Connect multimeter (resistance test range) between contacts 3 and 4 on the sender.

All models

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 attained:

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
.

Coolant temperature sender with square plug:

Test for open circuit and short to positive or earth in the following wiring connections:

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

Coolant temperature sender with oval plug:

Test for open circuit and short to positive or earth in the following wiring connections:

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

All models

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

If no wiring fault is detected:

Fit a new engine control unit => Page
24-23
.