Component Tests and General Diagnostics

Voltage Supply For Engine Control Module (ECM), Checking

Recommended special tools and equipment
- V.A.G 1526 multimeter or V.A.G 1715 multimeter
- V.A.G 1594 connector test kit
- Wiring diagram

Requirements







- The respective fuses of Diesel-Direct fuel injection system must be OK.
- Generator (GEN) OK.
- Battery voltage must be at least 11.5 volts.
- All electrical consumers such as, lights and rear window defroster must be switched off.
- For vehicles with automatic transmission, selector lever must be in position -P- or -N-.
- Parking brake must be engaged.
- If vehicle is equipped with an A/C system, it must be switched off.
- Ground (GND) connections between engine and chassis must be OK.

Test sequence
- Switch ignition off.
- Connect test box (1598/42) to Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) -J248- wiring harness using adapter cable (V.A.G 1598/39-2), connecting test box for wiring test. Test Box, Connecting For Wiring Test
- Measure voltage between the following sockets:

1/2/4 and 3/5/6
Specified value: approx. 0 V

- Switch ignition on.
- Measure voltage anew between the following sockets:

1/2/4 and 3/5/6
Specified value approx. battery voltage

- Switch ignition off.

If specified value is not obtained:
- Check Power Supply (Terminal 30, B+) Relay -J317-:
- Check wire connections at terminal locations for open circuit, short circuit and contact resistances according to wiring diagram.

If no malfunctions are found in wires and at relay:
- Replace Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) -J248-.