With Manufacturer's Scan Tool

Diesel (DFI) Engine Control Module (ECM) Voltage Supply - J248-, Checking

Engine control module voltage supply, checking

Special tools and equipment
- Digital multimeter US 1119 (Fluke 83 or equivalent)
- VAG 1594 Adapter kit
- VAG 1598/22 Test box (through my 1999)
- VAG 1598/31 Test box (from my 2000)
- Wiring diagram

Test conditions



- Fuses No.29 and 32 OK.
- Battery 11.5 Volts minimum.
- All electrical consumers, e.g. lights and rear window defog must be switched off.
- A/C switched off.
- Selector lever in position "P" or "N" (automatic trans.).

Test sequence
- Remove wiper arms and cowl panel




- Connect test box VAG 1598/22 (through my 1999) or VAG 1598/31 (from my 2000) to Engine Control Module (ECM) -J248- wiring harness, Testing and Inspection
- Bridge following sockets with auxiliary cables from VAG1594:
- Through MY 1999: 33 + 1
- From MY 2000 : 18 + 4
- Measure voltage between following sockets:
- Through MY 1999 : 2 + 1, 28 + 1, 27 + 2 and 28 + 27
- From MY 2000 : 4 + 1, 2 + 4, 5 + 1 and 5 + 2
Specification: approx. battery voltage

If specification not obtained:
- Check voltage supply relay terminal 30 (B+) -J317-.
- Check wiring connections for open circuit, short circuit and transfer resistance at contacts according to wiring diagram.

If wiring and relay are ok:
- Replace Engine Control Module (ECM) -J248-.