U1204 – BMW DTC

BMW DTC U1204 – Lost Communication With OBD Data Hybrid/EV Powertrain Control Module via FA-CAN

DTC U1204 meaning on BMW

The DTC U1204 code on a BMW indicates a communication error between the On-Board Diagnostic (OBD) data link connector and the Hybrid/EV Powertrain Control Module via the FA-CAN (FlexRay Controller Area Network) communication network. This error typically means that the communication between these modules has been lost or disrupted.

BMW DTC U1204 symptoms

Symptoms of the DTC U1204 code on a BMW may include:

• Check Engine Light (CEL) illuminated on the dashboard
• Loss of power or performance issues
• Problems with the hybrid or electric powertrain system

BMW DTC U1204 causes

The common causes of the DTC U1204 code on a BMW include:

• Faulty Hybrid/EV Powertrain Control Module
• Issues with the FA-CAN communication network
• Wiring or connection problems between the OBD data link connector and the control module

BMW DTC U1204 seriousness

The DTC U1204 code should be addressed promptly as it can affect the proper functioning of the hybrid or electric powertrain system in the BMW. Ignoring this code may lead to performance issues or potential safety concerns.

How to diagnose DTC U1204 on BMW

To diagnose the DTC U1204 code on a BMW, a mechanic would typically perform the following steps:

1. Use a diagnostic scanner to retrieve the fault codes stored in the vehicle’s computer
2. Inspect the wiring and connections between the OBD data link connector and the Hybrid/EV Powertrain Control Module
3. Check the FA-CAN communication network for any faults or disruptions
4. Test the Hybrid/EV Powertrain Control Module for proper functionality

How to fix DTC U1204 on BMW

To fix the DTC U1204 code on a BMW, the following steps may be taken:

1. Repair or replace any damaged wiring or connections between the OBD data link connector and the control module
2. Address any issues with the FA-CAN communication network
3. Replace the faulty Hybrid/EV Powertrain Control Module if necessary
4. Clear the fault codes using a diagnostic scanner after the repairs have been completed

How to erase DTC U1204 on BMW

To erase the DTC U1204 code on a BMW, follow these steps:

1. Connect a diagnostic scanner to the vehicle’s OBD port
2. Select the option to clear fault codes from the scanner menu
3. Follow the on-screen instructions to erase the DTC U1204 code
4. Ensure that the issue causing the code has been resolved before clearing the code

Recommended tools & DTC Scanners for BMW

Best Diagnostic App for modern BMWs: BimmerLink

Recommended Bluetooth adapter for Bimmerlink: OBDLink CX

Cable adapter for Bimmerlink: Enet Cable USB Type C

For older BMWs we recommend: Autel AutoLink AL319 (2024 version)

Easy-to-use Multimeter for reliable diagnostics: AstroAI Auto-ranging Multimeter

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