Manufacturer Code Charts: 3700

Control unit 'Fuel pump' : Short circuit to positive (P0629)


Possible cause:

- Fuel system control unit
Affected functions:

- Engine output

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Test 1: Signal wire PWM signal Fuel pump

1. Signal wire PWM signal Fuel pump
Figure legend

- A -ConnectionTest cable 35-pin socket box
- 001 -Sockets of component N3/10 (ME-SFI [ME] control unit)
- 05 -35-pin socket box
- 050 -126-pin socket box
- 108 -Test cable 266 589 01 63 00
- N3/10 (ME-SFI [ME] control unit)
- II 1-63ConnectionTest cable
- III 64-126ConnectionTest cable
Warning!

-
- Connection A of test cable 108 may NOT be connected to connection B of the 126-pin socket box (050).







Test sequence

- Switch off ignition.
- Connect socket box (126-pin) to component N3/10 (ME-SFI [ME] control unit).
- Measure direct current with multimeter between sockets [F.4] 100 and [F.17] 113 of the 126-pole socket box tester.
- Switch on ignition.
Specified value

- Amperage[8...15] mA
Question

- Is the measurement value OK?


YES
The measurement value is OK.Other possible cause of fault

- In the event of stored faults with a high fault frequency count or in the event of customer complaints, check lines and connectors for loose contact and corrosion..
- B4/15 (Fuel pressure sensor)
End of test

NO
The measurement value is not OK.Possible cause and remedy

- Check lines to components N118/3 (Left fuel pump control unit) and N118/4 (Right fuel pump control unit) as per wiring diagram.
Further possible remedies

- Read fault memories of the control units N118/3 (Left fuel pump control unit) and N118/4 (Right fuel pump control unit).