P1451 - Fuel Pump Relay Inoperative

[paul_bfree]

Hi all,
I've been chasing a fault with my 2007 A3 2.0TDI 125kW BMN relating to MIL on - Fuel Pump Relay fault.
I can not find any answer that helps on the forums. There are similar fault codes, but my problem is I have no power at the Fuel Pump Relay (Type 373?) Purple relay plug shown in photo. All cabin fuses are showing voltage at the outputs (after the fuse), so I don't have a blown fuse. I can't get Elsawin to work, so hoping someone can source me a circuit diagram of the fuel system so I can trace the wires (large Red and Black - probably +12VDC to fuel pump and smaller wires to control relay - Brown (GND) and Yellow/Black?- from ECU?).

VCDS readout (partial):
Friday,06,October,2023,12:58:43:35777
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 11 x64
VCDS Version: 23.3.1.0 (x64) HEX-V2 CB: 0.4631.4
Data version: 20230421 DS346.2
www.Ross-Tech.com


VIN: WAUZZZ8P07A098127 License Plate:
Mileage: 306663 kms Repair Order:



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Address 01: Engine Labels: 03G-906-018-BMN.clb
Control Module Part Number: 03G 906 018 DN HW: 03G 906 018 DN
Component and/or Version: R4 2.0l PPD1.2 G 4350
Software Coding: 0000078
Work Shop Code: WSC 40070 822 85997
VCID: 74B1D80512B393BA1B3-8020
2 Faults Found:

005441 - Fuel Pump Relay (J17)
P1541 - 009 - Open Circuit - MIL ON
Freeze Frame:
Fault Status: 11100100
Fault Priority: 1
Fault Frequency: 12
Reset counter: 40
Mileage: 306663 km
Time Indication: 0
Date: 2000.00.00
Time: 31:63:63

Freeze Frame:
RPM: 0 /min
Torque: 0.0 Nm
Speed: 0.0 km/h
0.00 %
Voltage: 11.98 V
Bin. Bits: 00000001
Temperature: 20.0 C

001668 - Glow Plug Control Module (J179)
P0684 - 006 - Implausible Signal - MIL ON
Freeze Frame:
Fault Status: 11100001
Fault Priority: 1
Fault Frequency: 6
Reset counter: 40
Mileage: 306663 km
Time Indication: 0
Date: 2023.10.05
Time: 15:00:30

Freeze Frame:
RPM: 128 /min
Torque: 0.0 Nm
Speed: 0.0 km/h
0.00 %
Voltage: 11.87 V
Bin. Bits: 00110000
Temperature: 20.0 C


Readiness: N/A

I am treating these two faults as the same as they both appeared together with the MIL illuminated.
I pulled the relay and it tested fine (OK).
Fuses appear to be in-tact.

No voltage at relay plug!
Thanks in advance.

 

[paul_bfree]

SOLVED - read a few issues online and, perhaps, in this forum. Apparently, ignore the Fuel Pump fault which is caused by the Glow Plug Control Module (J179) - Implausible Signal - MIL ON. The Automatic Glow Period Control Unit (J179) is a 'smart' relay that controls the glow plug period and, thru the ECU, the fuel pump relay. Replaced with a new part, cleared codes and all working now.