Engine Code 1Z

Special Tools, Testers And Auxiliary Items:
- VAG 1551/1552 Scan Tool with VAG 1551/3 adaptor cable
- Test Box VAG 1598/18
- Fluke 83 multimeter (or equivalent)
- VW 1594 adaptor kit
- Wiring diagram

Test Sequence:
- Connect VAG 1551/1552 Scan Tool
- Start engine and let idle
- Press 0 and 1 buttons to select address word 01 "engine electronics"
Display will appear as shown:

Rapid data transfer HELP
select function XX

- Press 0 and 8 buttons to select Function 08 "Read measuring value block"
- Press Q button to enter input
Display will appear as shown:

Read measuring value block HELP
Input display group number XXX

- Press 0, 0 and 7 buttons to select display group number 7
- Press Q button to enter input
Display will appear as shown:

Read measuring value block 7 ->
15.4°C 15.9°C 16.7°C

- Observe ECT value in display zone 4
value must increase uniformly and without interruption

NOTE: If the ECT sensor malfunctions, the fuel temperature sensor values are substituted to provide a backup.

If an unreasonable value appears in display zone 4 or the fuel temperature has been supplied as a substitute; check the ECT sensor and wiring connections to sensor as follows:
- Press -> button
- Press 0 and 6 buttons to select Function 06 end data transfer
- Press Q button to enter input
- Switch OFF ignition





- Disconnect ECT sensor harness connector from ECT sensor -1-
- Measure resistance between sensor terminals 1 + 3





Specification, see diagram
Scale A snows resistance values for temperature range 0 to 50°C
Scale B the values for temperature range 50 to 100°C.

Examples:
^ 30°C corresponds to a resistance of 1500 to 2000 Ohms
^ 80°C corresponds to a resistance of 275 to 375 Ohms

If specification not obtained:
- Replace Engine Coolant Temperature sensor G62
- Display the readiness code

If DTC memory was erased:
- Create readiness code again

If specification obtained:





- Connect VAG 1598/18 Test Box to ECM harness connector





- Check wiring between Test Box and 4 pin harness connector for open circuit using wiring diagram:
terminal 1 + socket 33
terminal 3 + socket 14
Wire resistance: max. 1.5 Ohms
- In addition, check wires for shorting to one another:
Specification: Infinite Ohms

If wiring OK:
- Replace ECM J248
- Erase DTC memory

NOTE: Disconnecting the Engine Coolant Temperature sensor automatically generates a DTC which must be erased.