Fuel Supply

Leak Detection Pump (LDP) V144, Checking (AMB Engine Code)

Special tools, testers and auxiliary items required
- Multimeter.
- Wiring diagram.

Test requirements







- The Leak Detection Pump (LDP) V144 fuse OK.
- The ignition switched off.

Procedure
- Remove the left rear wheel housing liner.







- Disconnect the Leak Detection Pump (LDP) V144 electrical harness connector - 2 -.

Checking internal resistance







- Using a Multimeter , check the Leak Detection Pump (LDP) V144 for resistance as follows:

Leak Detection Pump (LDP) V144 electrical Specified
harness connector terminals values
- 1 - + - 3 - 640 to 720 Ohms
- 2 - + - 3 - 15 to 17 Ohms

If any of the specifications are not obtained:
- Replace the Leak Detection Pump (LDP) -V144-.

If the specified values are obtained:

Checking voltage supply

NOTE: The voltage for the Leak Detection Pump (LDP) -V144- is supplied via the Engine Control Module (ECM) J220.

- Check the Leak Detection Pump (LDP) -V144- for voltage.







- Using a Multimeter , check the Leak Detection Pump (LDP) -V144- electrical harness connector terminal 3 for voltage.

Leak Detection Pump (LDP) -V144- Measure to
electrical harness connector terminal
-3- Engine Ground (GND)


- Operate the starter briefly.
Specified value: battery voltage.
- Switch the ignition off.

If the specified value was not obtained:







- Using a Multimeter , check the Leak Detection Pump (LDP) -V144- electrical harness connector terminal 3 to the Fuel Pump Relay J17 terminal 2 for an open circuit.
Specified value: Wire resistance max 1.5 Ohms.

If the specification is not obtained:
- Check the wiring for a short circuit to Battery positive (+) or an open circuit.
- Check the electrical harness connector for damage, corrosion, lose or broken terminals.
- If necessary, repair the faulty wiring connection.

If no malfunction is detected in the wiring and if the voltage supply was OK:

Checking wiring

If the manufacturers test box is being used. Perform the following step.
- Install the test box.

If the manufacturers test box is not being used. Perform the following step.
- Remove the Motronic Engine Control Module (ECM) J220.
- Using a Multimeter , check the Leak Detection Pump (LDP) -V144- electrical connector terminal 1 to Motronic Engine Control Module (ECM) J220 electrical connector terminal 80 for an open circuit.







- Using a Multimeter , check the Leak Detection Pump (LDP) -V144- electrical connector terminal 2 to Motronic Engine Control Module (ECM) J220 electrical connector terminal 25 for an open circuit.

Leak Detection Pump (LDP) - Motronic Engine Control
V144- electrical harness Module (ECM)J220 electrical
connector terminals connector terminals or test
box socket
1 80
2 25


Specified value: 1.5 Ohms max.

If the specification is not obtained:
- Check the wiring for a short circuit to Battery positive (+) or an open circuit.
- Check the electrical harness connector for damage, corrosion, lose or broken terminals.
- If necessary, repair the faulty wiring connection.

If no malfunction is found in wiring:
- Replace the Motronic Engine Control Module (ECM) J220.

Assembly is performed in the reverse order of the removal, note the following:
- Install the left rear wheel housing liner

Final procedures
After the repair work, the following work steps must be performed in the following sequence:
1. Check the DTC memory. Diagnostic Mode 03 - Read DTC Memory
2. If necessary, erase the DTC memory. Diagnostic Mode 04 - Erase DTC Memory
3. If the DTC memory was erased, generate readiness code.

- End of diagnosis.