With Generic Scan Tool

Voltage supply for Diesel-Direct Fuel Injection System, checking

Recommended special tools and equipment
- VAG1526 multimeter or VAG1715 multimeter
- VAG1594 connector test kit
- Wiring diagram

Test 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, for example, 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: about 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

Continuation 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 detected in wires and at relay:
- Replace Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) -J248-
- Erase DTC memory of control module for Diesel- Direct fuel injection system, Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 4: Reset/Erase Diagnostic Data
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes