Leak Detection Pump, Checking, Vehicles With FSI and TFSI Engine
Leak Detection Pump, Checking, Vehicles with FSI and TFSI Engine
Special tools, testers and auxiliary items required
• Hand-Held Multimeter (V.A.G 1526C)
• Voltage Tester (V.A.G 1527B)
• Connector Test Set (V.A.G 1594C)
• Adapter Cable (V.A.G 1598/39)
• Test Box (V.A.G 1598/42)
• Vehicle Diagnostic, Testing, and Information System (VAS 5051B)
Procedure
• Ignition switched on.
• Vehicle Diagnosis, Testing and Information System ( VAS 5051B) connected.
Check activation
Display on (VAS 5051B):
- Tap "On Board Diagnostic" in selection - 1 - and activate by tapping the -> button.
Display on (VAS 5051B):
- Tap "01 - Engine Electronics" vehicle system in selection - 1 - and activate by tapping the -> button.
Display on (VAS 5051B):
- Tap diagnostic function "005 - Output Diagnostic Test Mode (DTM)" in selection - 1 - and activate by pressing the -> button.
Display on (VAS 5051B):
A Output diagnostic test mode waiting, Advancing by switching required
1 Evaporative Emission (EVAP) Canister Purge Regulator Valve (N80)
- Press the -> button repeatedly, until leak detection pump for fuel system is activated.
• The sound of the leak detection pump running can be heard at the left rear wheel housing.
- End function "005 - output Diagnostic Test Mode (DTM)" by pressing <- button.
- Select diagnostic function "022 - End output" in selection.
- Switch off ignition.
If Leak Detection Pump (LDP) for fuel system is not activated (no operating noise audible):
- Remove leak detection pump (LDP) (V144), refer to => [ Leak Detection Pump ] Service and Repair and disconnect the electrical connection.
Checking internal resistance
- Connect hand multimeter (V.A.G 1526C) for resistance measurement as follows.
If specifications are not obtained:
- Replace the Leak Detection Pump (LDP) (V144). Refer to => [ Leak Detection Pump ] Service and Repair.
If specified values are achieved:
- Check voltage supply of leak detection pump.
Checking voltage supply
• Voltage for leak detection pump is supplied via Motronic Engine Control Module (ECM) Power Supply Relay (J271).
Test Conditions
• Fuse for leak detection pump OK
- Connect Voltage Tester (V.A.G 1527B) as follows:
- Briefly operate starter.
• LED must light up.
If LED does not light up:
- Check electrical harness connection from terminal - 3 - via fuse to Motronic Engine Control Module (ECM) Power Supply Relay (J271) for open circuit according to wiring diagram.
- Repair open circuit in wiring according to wiring diagram.
Checking output wiring
- Connect Voltage Tester (V.A.G 1527B) as follows:
- Initiate output Diagnostic Test Mode (DTM).
Display on (VAS 5051B):
A Output diagnostic test mode waiting, Advancing by switching required
1 Evaporative Emission (EVAP) Canister Purge Regulator Valve (N80)
- Press the -> button repeatedly, until leak detection pump for fuel system is activated.
• LED must blink.
If LED does not blink:
- End function "005 - output Diagnostic Test Mode (DTM)" by pressing <- button.
- Select diagnostic function "022 - End output" in selection.
- Switch off ignition.
- Connect Test Box (V.A.G 1598/42) to wiring harness with Adapter Cable (V.A.G 1598/39-1) or Adapter Cable (V.A.G 1598/39-2). Clamp test box Ground (GND) clip to battery negative terminal. The procedure will indicate whether the engine control module is to be connected to the test box or not.
CAUTION!
To avoid damaging electronic components, switch to the corresponding measuring range and observe all test conditions before connecting the test leads.
- Check the following wire connection for open circuit and short circuit to Ground (GND) and B+:
- Repair wiring open circuit or short circuit according to wiring diagram.
If no malfunction is found, but leak diagnosis pump is not functional during output diagnostic test mode:
- Replace the Leak Detection Pump (LDP) (V144). Refer to => [ Leak Detection Pump ] Service and Repair.
- Observe procedures for after re-connecting engine control module (ECM).
Checking input wiring
- Switch off ignition.
- Connect Test Box (V.A.G 1598/42) to wiring harness with Adapter Lead (V.A.G 1598/39-1) or Adapter Lead (V.A.G 1598/39-2). Clamp test box Ground (GND) clip to battery negative terminal. The procedure will indicate whether the engine control module is to be connected to the test box or not.
CAUTION!
To avoid damaging electronic components, switch to the corresponding measuring range and observe all test conditions before connecting the test leads.
- Check the following wire connection for open circuit and short circuit to Ground (GND) and B+:
- Repair wiring open circuit or short circuit according to wiring diagram.
- Observe procedures for after re-connecting engine control module (ECM).