Leak Detection Pump: Testing and Inspection
Check Leak Detection Pump (LDP)
Recommended special tools and equipment
- VAG 1526 multimeter or VAG 1715 multimeter
- VAG 1594 connector test kit
- Wiring diagram
Test requirements
- The respective fuses of Leak detection pump (LDP) -V144- must be OK.
- Ignition switched off.
Test sequence
- Remove rear right wheelhouse liner.
- Disconnect 3-pin connector of Leak Detection Pump (LDP) -V144- (arrow).
- Measure resistance between terminals 1 + 3 of diagnostic pump. Specified value: 640...720 Ohms
Vehicles with engine code AEG, AVH, AZG
- Measure resistance between terminals 2 + 3 of diagnostic pump. Specified value: 12.5...19.5 Ohms
Vehicles with engine code BDC
- Measure resistance between terminals 2 + 3 of diagnostic pump. Specified value: 17.5...19.5 Ohms
Continuation for all vehicles
If specified values are not obtained:
- Replace Leak Detection Pump (LDP) -V144-, item 1
- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 4: Reset/Erase Diagnostic Data
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes
If specified values are obtained:
- Connect test box to control module wiring harness, connect test box for wiring test. Test Box, Connecting For Wiring Test
Vehicles with engine code AEG
- Check wires between test box and 3-pin connector for open circuits according to wiring diagram. Terminal 1 + socket 37, Terminal 2 + socket 16: Wire resistance: max. 1.5 Ohms
Vehicles with engine code AVH, AZG, BDC
- Check wires between test box and 3-pin connector for open circuits according to wiring diagram. Terminal 1 + socket 80, Terminal 2 + socket 25: Wire resistance: max. 1.5 Ohms
Continuation for all vehicles
- Also check wires for short circuit to each other, to vehicle Ground (GND) and to B+.
Specified value: Infinite Ohms
- Check wire between 3-pin connector terminal 3 and the Fuel Pump (FP) Relay -J17- for open circuit according to wiring diagram. Wire resistance: max. 1.5 Ohms
If no malfunctions are found in wires:
- Replace Motronic Engine Control Module (ECM) -J220-.