Leak Detection Pump, Checking

Special Tools And Workshop Equipment Required 

• Multimeter.
• Wiring diagram.

Test Requirements 

• The Leak Detection Pump (LDP) -V144- fuse 15 in fuse panel B is OK.
• The ignition switched off.

Test Procedure 

-- Perform a preliminary check to verify the customers complaint. Refer to PRELIMINARY CHECK 

Start Diagnosis 

-- Remove the right rear wheel housing liner. Refer to the appropriate Service Information.

-- 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 connector terminals	Specified values
-1- to -3-	640 to 720 Ω
-2- to -3-	15 to 17 Ω

If the specified values were Not obtained:

-- Replace the Leak Detection Pump (LDP) --V144--. Refer to the appropriate Service Information.

If the specified values were obtained:

Checking voltage supply

-- 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. Connect the negative multimeter lead to engine ground.

-- Turn the ignition switch ON.

Specified value: Battery voltage. 

-- Switch the ignition OFF.

If the specified value was Not obtained:

-- Remove fuse 15 in Fuse Panel B. Using a multimeter, check the Leak Detection Pump (LDP) --V144-- wiring from terminal 3 to fuse 15 in Fuse Panel B.

Specified value: 1.5 Ω max. 

If the specified value was Not obtained:

-- Check the wiring for high resistance, short to ground or an open circuit.

-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.

-- If necessary, repair the faulty wiring connection.

If the specified value was obtained:

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) -J623-. Refer to the appropriate Service Information.

-- Using a multimeter, check the Leak Detection Pump (LDP) --V144-- electrical connector terminals to Motronic Engine Control Module (ECM) -J623- electrical connector terminals for an open circuit or high resistance.

Leak Detection Pump (LDP) --V144-- electrical harness connector terminal	Motronic Engine Control Module (ECM) -J623- electrical connector T94 terminal or test box socket
1	44
2	49

Specified value: 1.5 Ω max. 

If the specified value was Not obtained:

-- Check the wiring for high resistance or an open circuit.

-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.

-- If necessary, repair the faulty wiring connection.

If no malfunction is found in wiring:

-- Replace the Motronic Engine Control Module (ECM) -J623-. Refer to the appropriate Service Information.

Assembly is performed in the reverse order of the removal, note the following:

-- Install the right rear wheel housing liner. Refer to the appropriate Service Information.

Final Procedures 

After the repair work, the following work steps must be performed in the following sequence:

1. Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY .
2. If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
3. If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .