Leak Detection Pump (LDP), Checking
Leak Detection Pump (LDP), Checking
Recommended special tools and equipment
- V.A.G1526 multimeter or V.A.G1715 multimeter
- V.A.G1594 connector test kit
- Wiring diagram
Test requirements
- Fuses in E-box (plenum chamber, left) must be OK
- Motronic Engine Control Module (ECM) Power Supply Relay -J271- -position A3- must be OK, check
- Ground (GND) connections between engine and chassis must be OK.
- Ignition switched off.
Test sequence
- Remove rear right wheel housing liner.
- Disconnect 3-pin connector of Leak detection pump (LDP) -V144- (-2-).
Checking resistances
- Measure resistance between terminals 1 + 3 of diagnostic pump.
Specified value: 640 to 720 ohms
- Measure resistance between terminals 2 + 3 of diagnostic pump.
Specified value: 12.0 to 20.0 ohms
If specified values are not obtained:
- Replace Leak Detection Pump (LDP) -V144-
- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 04 - Erase DTC Memory
- Generate readiness code. Readiness Code
If specified values are obtained:
- Check wires according to wiring diagram.
Checking wiring
- Connect test box to control module wiring harness, connect test box for wiring test. Test Box, Connecting For Wiring Test
- 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
- Also check wires for short circuit to each other, to vehicle Ground (GND) and to B+.
Specified value: infinity ohm
- Check wire between 3-pin connector terminal 3 and Motronic Engine Control Module (ECM) Power Supply Relay -J271- for open circuit according to wiring diagram.
Wire resistance: max. 1.5 ohms
- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 04 - Erase DTC Memory
- Generate readiness code. Readiness Code
If no malfunctions are found in wires:
- Replace Motronic Engine Control Module (ECM) -J220-.