Component Tests and General Diagnostics

Voltage Supply For Diesel-Direct Fuel Injection System, 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-
- 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 to control module wiring harness. connect test box for wiring test. Test Box, Connecting For Wiring Test

Vehicles with 80-pin control module
- Bridge sockets 33 + 1 using adapter cables from V.A.G 1594.
- Switch ignition on.
- Measure voltage between the following sockets:
2 + 1, 28 + 1, 27 + 2 and 28 + 27

Specified value: approx. battery voltage

Vehicles with 121-pin control module
- Measure voltage between the following sockets:
1/2 and 4/5
37 and 4/5

Specified value: approx. 0 V

- Switch ignition on.
- Measure voltage anew between the following sockets:
1/2 and 4/5
37 and 4/5

Specified value approx. battery voltage

Vehicles with 154-pin control module
- Connect adapter cable (V.A.G 1598/39-2) to test box (V.A.G 1598/42).
- Measure voltage between the following sockets:
1/2/4 and 3/5/6

Specified value: approx. 0 V

- Switch ignition on.
- Measure voltage again between the following sockets:
1/2/4 and 3/5/6

Specified value approx. battery voltage

Continue for all vehicles
If specified value is not obtained:

- Check Power Supply (Terminal 30, B+) Relay -J317-:

- Check wire connections at the 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-.
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes