Diesel MFI Pump: Testing and Inspection
Pump-Injector Unit, Checking
Only vehicles with engine code BEW
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: Electrical Wiring Diagrams, Troubleshooting & Component Locations
- Battery voltage must be at least 11.5 volts.
Test sequence
- Disconnect harness connector for Pump-Injector Unit from cylinder head.
- Check resistance of Pump-Injector Unit valves between connector terminals.
Cyl. 1: Terminals 7 + 5
Cyl. 2: Terminals 7 + 3
Cyl. 3: Terminals 7 + 2
Cyl. 4: Terminals 7 + 6
Specified value: 0.1 to 1.0 ohms
- Check wires for short circuit to each other as well as to vehicle Ground (GND).
Specified value: infinity ohms
If specified value is obtained:
- Check wires to control module according to wiring diagram.
If specified value is not obtained:
- Remove upper toothed belt guard and cylinder head cover.
- Pry off connectors of all 4 pump-injector units using a screwdriver. In order to avoid canting, support opposite side of connector with light finger pressure.
- Check resistance of Pump-Injector Unit valves between connector terminals at Pump- Injector Unit valves.
Specified value: approx. 0.5 ohms
If specified value is not obtained:
- Replace malfunctioning Valve for pump/injector, cylinder 1 -N240- to Valve for pump/injector, cylinder 4 -N243-, removing and installing Pump-Injector Unit.
- Erase DTC memory of control module for Diesel-Direct fuel injection system, Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 04 - Erase DTC Memory
- Generate readiness code.
If specified value is obtained:
- Check wires between harness connector for Pump-Injector Unit and all 4 connectors (terminal 2) for open circuit.
Cyl. 1: Terminal 2 (gray) + terminal 5
Cyl. 2: Terminal 2 (red) + terminal 3
Cyl. 3: Terminal 2 (yellow) + terminal 2
Cyl. 4: Terminal 2 (white) + terminal 6
Wire resistance: max. 1.5 ohms
- Check wires between harness connector for Pump-Injector Unit and all 4 connectors (terminal 1) for open circuit.
Terminal 1 (brown) + terminal 7
Wire resistance: max. 1.5 ohms
- Check wires for short circuit to each other.
Specified value: infinity ohms
Check wires to control module
- Connect test box to control module wiring harness, connect test box for wiring test.
- Connect adapter cable (V.A.G 1598/39-1) to test box (V.A.G 1598/42).
- Check wires between test box and connector for open circuit according to wiring diagram.
Terminal 2 + socket 47
Terminal 3 + socket 1
Terminal 5 + socket 46
Terminal 6 + socket 48
Terminal 7 + socket 31
Wire resistance: max. 1.5 ohms
- Check wires for short circuit to each other, to vehicle Ground (GND) and to B+.
Specified value: infinity ohms
If no malfunctions are found in wires:
- 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 04 - Erase DTC Memory
- Generate readiness code.