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Checking voltage supply Audi A4 B6

Fuel Supply System ~596 words

Checking voltage supply

Note. Voltage for leak detection pump is supplied via Motronic Engine Control Module (ECM) Power Supply Relay J271.

Test conditions

  1. Fuse for leak detection pump OK
  1. Connect voltage tester V.A.G 1527 B as follows
Harness connector TerminalMeasure to
3Engine Ground (GND)
  1. Briefly operate starter.
  1. LED must light up.

If LED does not light up

  1. 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.
  1. Repair open circuit in wiring according to wiring diagram.
  1. Connect voltage tester V.A.G 1527 B as follows
Harness connector TerminalMeasure to
2Battery positive (B+)
  1. Initiate output Diagnostic Test Mode (DTM) Check activation .

Display on VAS 5051

A - Output diagnostic test mode waiting, Advancing by switching required

1 - Evaporative Emission (EVAP) Canister Purge Regulator Valve N80

  1. Press --> button repeatedly until leak detection pump for fuel system is activated
  1. LED must blink.

If LED does not blink

  1. End function "03 - output Diagnostic Test Mode (DTM)" by pressing <-- button.
  2. From selection, click on diagnostic function "06 - End output".
  3. Switch off ignition.
  1. 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.
CAUTIONTo avoid damaging electronic components, switch to the corresponding measuring range and observe all test conditions before connecting the test leads.
  1. Check the following wire connection for open circuit and short circuit to Ground (GND) and B+
Harness connector TerminalV.A.G 1598/42 Bushing
24-Cyl. TFSI: B 8
6-Cyl. FSI: B 24
8-cyl. FSI - Audi RS4: A 55
  1. 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

  1. Replace Leak Detection Pump (LDP) V144 --> Leak Detection Pump (LDP) V144 , removing and installing .
  2. Observe procedures for after re-connecting engine control module (ECM) --> 24 MULTIPORT FUEL INJECTION (MFI) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMB 24 - MULTIPORT FUEL INJECTION (MFI) for 2.0 LITER 4-CYL. 4V TURBO FUEL INJECTION IGNITION, ENGINE CODE(S): BPG, BWT 24 MULTIPORT FUEL INJECTION (MFI) for 3.0 LITER 6-CYL. 5V FUEL INJECTION & IGNITION, ENGINE CODE(S): AVK, BGN 24 - FUEL INJECTION SYSTEM for 3.2 V6 4V FUEL INJECTION IGNITION, ENGINE CODE(S): BKH 24 - MULTIPORT FUEL INJECTION (MFI) for 4.2 LITER V8 4V FUEL INJECTION AND IGNITION, ENGINE CODE(S): BNS 24 MULTIPORT FUEL INJECTION (MFI) for 4.2 LITER V8 5V FUEL INJECTION AND IGNITION, ENGINE CODE(S): BHF .
  1. Switch off ignition.
  1. 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.
CAUTIONTo avoid damaging electronic components, switch to the corresponding measuring range and observe all test conditions before connecting the test leads.
  1. Check the following wire connection for open circuit and short circuit to Ground (GND) and B+
Harness connector TerminalV.A.G 1598/42 Bushing
14-cyl. TFSI: B 48
6-cyl. FSI: B 24
8-cyl. FSI - Audi RS4: B 40
  1. Repair wiring open circuit or short circuit according to wiring diagram.
  2. Observe procedures for after re-connecting engine control module (ECM) --> 24 MULTIPORT FUEL INJECTION (MFI) for 1.8 LITER 4-CYL. 5V TURBO FUEL INJECTION & IGNITION, ENGINE CODE(S): AMB 24 - MULTIPORT FUEL INJECTION (MFI) for 2.0 LITER 4-CYL. 4V TURBO FUEL INJECTION IGNITION, ENGINE CODE(S): BPG, BWT 24 MULTIPORT FUEL INJECTION (MFI) for 3.0 LITER 6-CYL. 5V FUEL INJECTION & IGNITION, ENGINE CODE(S): AVK, BGN 24 - FUEL INJECTION SYSTEM for 3.2 V6 4V FUEL INJECTION IGNITION, ENGINE CODE(S): BKH 24 - MULTIPORT FUEL INJECTION (MFI) for 4.2 LITER V8 4V FUEL INJECTION AND IGNITION, ENGINE CODE(S): BNS 24 MULTIPORT FUEL INJECTION (MFI) for 4.2 LITER V8 5V FUEL INJECTION AND IGNITION, ENGINE CODE(S): BHF .