With Manufacturer's Scan Tool

Engine Coolant Temperature (ECT) Sensor -G62-, Checking

Special tools and equipment
- Scan Tool VAG 1551 or vehicle system tester
- VAG 1552 with cable VAG 1551/3
- Test box VAG 1598/31
- Hand multimeter VAG 1526 or multimeter VAG 1715
- Adapter set VAG 1594
- Wiring diagram

Test conditions
- Engine must be cold.

Test sequence
- Connect VAG 1551/1552 (Connecting scan tool and selecting engine electronics control module.) Run engine at idle speed and press buttons -0- and -1- to select "Engine electronics" address word 01. [1][2][3]Connecting VAG 1551 Scan Tool

Indicated on display:

Rapid data transfer HELP
Select function XX

- Press buttons -0- and -8- for the function "Read measured value block" and confirm entry with -Q- button.

Indicated on display:

Read measured value block
Enter display group number XXX

- Press buttons -0-, -0- and -7- for "Display group number 7" and confirm entry with -Q- button.

Indicated on display:

Read measured value block 7 ->
15.4 degree C 15.9 degree C 16.7 degree C

- Observe coolant temperature figure in display field 4. The temperature figure must increase uniformly and without interruption.
- In case of faults the fuel temperature is displayed as a substitute.
- If no realistic display appears in display field 4 or the fuel temperature is displayed as a substitute. Check coolant temperature sensor and wiring connections to sensor as follows.
- Press the -> button.
- Press buttons -0- and -6- for the function "End output" and confirm entry with the -Q- button.
- Switch off ignition.






- Disconnect the connector from coolant temperature sensor.
- Measure resistance between sender contacts C -1- +D -3-.






Specification see diagram

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

Examples:
- 30 degree C corresponds to a resistance from 1500 to 2000 Ohm
- 80 degree C corresponds to a resistance from 275 to 375 Ohm

If the specification is not obtained:
- Replace ECT Sensor -G62-.
- Check DTC memory and, if necessary, repair any malfunctions and then erase. [1][2]Reading Diagnostic Trouble Codes
- Read-out the readiness code. If the DTC memory has been erased or the Diesel Direct Fuel Injection Engine Control Module - J248- was disconnected from permanent battery positive (B+), the readiness code must be generated again.
Monitors, Trips, Drive Cycles and Readiness Codes
Monitors, Trips, Drive Cycles and Readiness Codes

If the specification is obtained:
- Remove wiper arms and plenum cover:






- Connect test box VAG 1598/31 to control unit wiring harness.






- Check wiring between test box and 4-pin connector for open circuit using wiring diagram.
Terminal 3 + socket 112
Terminal 4 + socket 104
Wire resistance: max. 1.5 Ohm

- Check wires for short to one another, to vehicle Ground and to battery positive (B+).
Specification: Infinite Ohm

- If wiring and the resistance measurement values are OK, replace Diesel Direct Fuel Injection Engine Control Module -J248-.