Leak Detection Pump, Checking
Special tools and workshop equipment required
- Multimeter.
- Wiring diagram.
Test requirements
- The Leak Detection Pump (LDP) -V144- fuse is OK.
- The engine must be completely cooled down. IAT must match ECT within 5 Degrees C in order for the LDP to operate. Let sit overnight if possible when testing for voltage to the pump motor.
- 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 Repair 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 harness connector terminals | Specified values |
|---|---|
| 1 and 3 | 640 to 720 Ω |
| 2 and 3 | 12.5 to 19.5 Ω |
If any of the specifications are Not obtained:
-- Replace the Leak Detection Pump (LDP) --V144--. Refer to the Repair information.
If the specified value was 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.
-- Start the engine.
Specified value: Battery voltage.
-- Switch the ignition OFF.
If the specified value was Not obtained:
-- Remove fuse S-243. Using a multimeter, check the Leak Detection Pump (LDP) --V144-- wiring from terminal 3 to fuse S-243.
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 detected in the wiring or 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-. Refer to the Repair information.
-- Using a multimeter, check the Leak Detection Pump (LDP) --V144-- electrical connector terminal 1 to Motronic Engine Control Module (ECM) -J220- electrical connector T121 terminal 80 for an open circuit or high resistance.
-- Using a multimeter, check the Leak Detection Pump (LDP) --V144-- electrical connector terminal 2 to Motronic Engine Control Module (ECM) -J220- electrical connector T121 terminal 25 for an open circuit or high resistance.
Specified value: 1.5 Ω max.
If the specified value was Not obtained:
-- Check the wiring for high resistance, a short circuit to Battery positive (+) 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) -J220-. Refer to the Repair information.
Assembly is performed in the reverse order of the removal, note the following:
-- Install the right rear wheel housing liner. Refer to the Repair information.
Final procedures
After the repair work, the following work steps must be performed in the following sequence:
- Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY .
- If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
- If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .