U1804 – BMW DTC

BMW DTC U1804 – Hybrid/EV Powertrain Control Module Lost Communication With HIM (Hybrid Interface Module) via HL-CAN

DTC U1804 meaning on BMW

The Diagnostic Trouble Code (DTC) U1804 for BMW indicates that there is a communication error between the Hybrid/EV Powertrain Control Module and the Hybrid Interface Module (HIM) via the HL-CAN (Hybrid Local Controller Area Network).

BMW DTC U1804 symptoms

Symptoms of the BMW DTC U1804 may include:

• Check Engine Light (MIL) illuminated
• Hybrid/EV system may not function properly
• Loss of communication with the HIM

BMW DTC U1804 causes

Possible causes of the BMW DTC U1804 include:

• Faulty Hybrid Interface Module (HIM)
• Issues with the HL-CAN communication network
• Wiring or connection problems

BMW DTC U1804 seriousness

The DTC U1804 on a BMW is considered serious as it can affect the proper functioning of the Hybrid/EV powertrain system. Ignoring this issue may lead to further complications and potential drivability problems.

How to diagnose DTC U1804 on BMW

To diagnose the DTC U1804 on a BMW, you can follow these steps:

1. Use a diagnostic scanner to retrieve the fault codes
2. Check the communication between the Hybrid/EV Powertrain Control Module and the HIM
3. Inspect the wiring and connections related to the HL-CAN network
4. Perform a visual inspection for any visible damage or loose connections

How to fix DTC U1804 on BMW

To fix the DTC U1804 on a BMW, you can try the following:

1. Inspect and repair any damaged wiring or connections
2. Replace the faulty Hybrid Interface Module (HIM) if necessary
3. Clear the fault codes using a diagnostic scanner
4. Perform a test drive to ensure the issue has been resolved

How to erase DTC U1804 on BMW

To erase the DTC U1804 on a BMW, you can use a diagnostic scanner to clear the fault codes. Follow these steps:

1. Connect the diagnostic scanner to the vehicle’s OBD-II port
2. Select the option to erase fault codes
3. Confirm the action and wait for the process to complete
4. Verify that the DTC U1804 has been successfully erased

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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