Leak Detection Pump (LDP), checking: Notes

Recommended special tools and equipment 

• V.A.G 1526 multimeter or V.A.G 1715 multimeter
• V.A.G 1594 connector test kit
• Wiring diagram

Test requirements 

• Fuses in E-box (plenum chamber, right) must be OK:

Refer to Electrical Wiring Diagrams and Component Locations

• Motronic Engine Control Module (ECM) Power Supply Relay -J271-, position 4, must be OK, check:

Refer to Electrical Wiring Diagrams and Component Locations

• Ground (GND) connections between engine and chassis must be OK.
• Ignition switched off.

Test sequence 

• Disconnect 3-pin connector of Leak detection pump (LDP) -V144- (arrow).

Checking resistances 

• Measure resistance between terminals 1 + 3 of diagnostic pump.

Specified value: 640 to 720 Ω

• Measure resistance between terminals 2 + 3 of diagnostic pump.

Specified value: 12.0 to 20.0 Ω

If specified values are not obtained:

• Replace Leak detection pump (LDP) -V144-. Refer to EVAP canister system components, removing and installing , EVAP canister system components, removing and installing 
• Erase DTC memory of Engine Control Module (ECM). Refer to Diagnostic mode 4: Reset/erase diagnostic data , Diagnostic mode 4: Reset/erase diagnostic data.
• Generate readiness code. Refer to Readiness code, generating .

If specified values are obtained:

• Check wires according to wiring diagram. Refer to Checking wiring .