Leak Detection Pump, Checking
Leak Detection Pump, Checking
Special tools, testers and auxiliary items required
- Multimeter.
- Wiring diagram.
Test requirements
- Fuse S234 OK.
- The Fuel Pump (FP) Relay J17 OK.
- The ignition switched off.
Test procedure
- Perform a preliminary check to verify the customers complaint. General Diagnosis
- Remove the left rear wheel housing liner.
Start diagnosis
- Remove the right front wheel.
- Remove the right front wheel housing liner.
- 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) Specified values
catalytic converter harness
connector terminals
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 by the Fuel Pump (FP) Relay J17.
- Using a Multimeter, check the Leak Detection Pump (LDP) -V144- electrical harness connector terminal 3 for voltage.
Leak Detection Pump (LDP) Measure to
-V144- electrical harness
connector terminals
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 (FP) Relay J17 socket 19/86 for resistance.
Specified value: 1.5 Ohms max
If the specification was not obtained:
- Check the wiring for 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 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 VAG1598/31.
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 harness connector terminal 1 to Motronic Engine Control Module (ECM) J220 electrical harness connector terminal 80 for resistance.
- Using a Multimeter, check the Leak Detection Pump (LDP) -V144- electrical harness connector terminal 2 to Motronic Engine Control Module (ECM) J220 electrical harness connector terminal 25 for resistance.
Leak Detection Pump (LDP) Motronic Engine Control Module
-V144- electrical connector (ECM) J220 harness connector
terminals terminals or test box sockets
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 (+), Ground (GND) 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:
- Erase the DTC memory. Diagnostic Mode 04 - Erase DTC Memory
- Perform a road test to verify repair.
If the DTC does not return:
Repair complete, Generate readiness code. Readiness Code
- End diagnosis.
If the DTC does return and no malfunction is detected in the wiring and the voltage supply was OK:
- Replace the Motronic Engine Control Module (ECM) J220.
- Assembly is performed in the reverse of the removal.
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