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Technical Service Bulletin
27 48V MHEV Electrical System Fault with DTC U046900 / 34763; U002900/U002800
United States 444 Volkswagen of America, Inc. (6444)
[Status | Released for publishing
Release date Mar 6, 2025
Diagnostic trouble codes
. . . - Fault Storage

Diagnostic address |Diagnostic trouble code
0001 - Engine U012000: Lost Communication With Starter / Generator ,

7 Intermittent
electronics Control Module
0001 - Engine U012000: Lost Communication With Starter / Generator .

i static
electronics Control Module
0001 - Engine U046900: Invalid Data Received From Starter / Generator Intermittent
electronics Control Module
0001 - Engine U046900: Invalid Data Received From Starter / Generator ,

- static
electronics Control Module
0001 - Engine U002800: Vehicle Communication Bus A | Intermittent
electronics
0001 - Engine . og .
0001 - Engine . woe .
002900: Vehicle Communication Bus A Performance | Intermittent
0001 - Engine 002900: Vehicle Communication Bus A Performance static
electronics
0003 - Brake C054A00: Vacuum Sensor "A" Range/Performance Intermittent
electronics
9003 - Brake C054A00: Vacuum Sensor "A" Range/Performance static
electronics
0008 - Brake C11EC04: Brake booster pressure sensor faulty | | Intermittent
electronics
0003 - Brake . .
C11EC04: Brake booster pressure sensor faulty stato
New customer code
Object of complaint Complaint type [Position]
information, navigation, communication, entertainment -> malfunction display functionality ->
symbols -> vehicle electrical system malfunction indicator activates
information, navigation, communication, entertainment -> information display functionality ->
symbols -> battery charge level information display activates

[object of complaint (| Comptaint type [Position]
icieoanieemmseeemme
Vehicle data

Sales types

aa_zosfa |

jaar Jaozofa |

jaar faorfa |

[anv faozfa |

anv _faozsfa |

jac: faorfa |

jax: faozofa fT

jax faozifa |

lace [zozzfa |

jas [aozsfa |

lame faorgfa |

jam aozofa [|

jam faozfa fT

jam faozfa |

jam faozsfa |

jan: faorfa PO

lan [zorofa ff

lant fzozifa fh

jan Jaozfa |

lant Jaozsfa [RR

PR numbers

Control units

loncc-starergenerar|> SS idosaa
(o0cC-Stanergeneratr[> Sida? =SSSOiSSS
(00cC Starner generator[> —SSSC*dse SSS
lo0cc starter generator[) —~SCS~C~*~idsSSCiSCSC“*‘~i~RSSSC*‘C~*d
Documents

master.xml

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Technical Service Bulletin Transaction No.: 2073284/4
27 48V MHEV Electrical System Fault with DTC U046900 / 34763; U002900/U002800 Release date: Mar 6, 2025
Condition
REVISION HISTORY
Revision [pate [Pupose
Revised header (Updated module software)
Revised Service (Updated information)
3 07/31/2024 Revised header (Updated DTC list)
Revised Service (Added details for diagnosis)
2 06/05/2024 Revised header (Added module software filters)
Revised Service (Added pictures and information for inspecting connectors)
Customer states:
+ Electrical system fault appears in the instrument cluster.
+ Yellow/red battery warning symbol lights up in the instrument cluster.
Workshop findings:
The complaint can be reproduced.
Address word 00CC (belt-driven starter-alternator) cannot be reached.
Numerous DTCs are stored relating to the Engine Electronics, -J623- (address word 0001) or Brake Electronics, -
J104- (address word 0003):
Engine Electronics, 0001:
+ U046900: Lost Communication with Starter/Generator Control Module —- Symptom: 34763.
+ U002900: Sensor/Hybrid CAN No Communication.
+ _U002800: Sensor/Hybrid CAN Faulty.
Brake Electronics, 0003:
+ C054A00: Brake Servo Pressure Sensor.
+ C©11EC04: Brake Servo Pressure Sensor.
Technical Background
Replacing the 48V Starter/Generator will not fix this problem. The DTC “U046900: Lost Communication with
Starter/Generator Control Module — symptom: 34763” is only stored due to some other electrical system problem in
the vehicle. This is often documented in the expanded ambient conditions of the event memory using the value
“Starter generator, actual mode 48V = 8”.