Leak Detection Pump Checking

Special tools and workshop equipment required 

• Multimeter.
• Wiring diagram.

Test requirements 

• Fuse -SB44- OK.
• The ignition switched off.

Test procedure 

-- Observe safety precautions. Refer to SAFETY PRECAUTIONS 

-- Observe Clean Working Conditions. Refer to CLEAN WORKING CONDITIONS 

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

Start diagnosis 

-- Remove the right rear wheel housing liner. Refer to Body Repair information.

-- Disconnect the Leak Detection Pump (LDP) -V144- electrical harness connector -3-.

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 value
-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 Repair information.

If the specified values are obtained:

Checking voltage supply 

-- Start the engine.

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

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

Specified value: battery voltage.

-- Switch the engine off.

If the specified value was not obtained:

-- Check the wiring from the Leak Detection Pump (LDP) --V144-- electrical harness connector terminal 3 to fuse 44 in Fuse Panel B for high resistance, an open circuit or a short circuit to Ground (GND).

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

-- If necessary, repair the wiring connection.

If the specified value was obtained:

Checking output 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 Repair information.

-- Using a multimeter, check the Leak Detection Pump (LDP) --V144-- electrical connector terminals to Motronic Engine Control Module (ECM) -J623- electrical connector T94 terminals for an open circuit.

Leak Detection Pump (LDP) --V144-- electrical connector terminals	Motronic Engine Control Module (ECM) -J623- electrical connector T94 terminals or test box socket
1	40
2	8

Specified value: 1.5 Ω.

If the specified value is not obtained:

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

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

-- If necessary, repair the wiring connection.

-- Erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .

-- Perform a road test to verify repair.

If the DTC does not return:

Generate readiness code. Refer to READINESS CODE .

If the DTC does return, no malfunction is detected in the wiring and the voltage supply is OK:

-- Replace the Motronic Engine Control Module (ECM) -J623-. Refer to the Repair information.

-- Assembly is performed in the reverse of the removal.

Final procedures 

After repair work, the following work steps must be performed in the mentioned 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 .