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U1801 – BMW DTC

BMW DTC U1801 – Hybrid/EV Powertrain Control Module Lost Communication With ECM via HL-CAN

DTC U1801 meaning on BMW

The Diagnostic Trouble Code (DTC) U1801 for BMW indicates that there is a communication error between the Hybrid/EV Powertrain Control Module and the Engine Control Module (ECM) via the High-Speed Controller Area Network (HL-CAN) bus.

BMW DTC U1801 symptoms

Symptoms of the BMW DTC U1801 may include:

  • Check Engine Light (CEL) illuminated on the dashboard
  • Hybrid/EV system may not operate as expected
  • Loss of communication between control modules

BMW DTC U1801 causes

Common causes of the BMW DTC U1801 may include:

  • Faulty wiring or connectors in the communication network
  • Defective Hybrid/EV Powertrain Control Module
  • Issues with the Engine Control Module (ECM)

BMW DTC U1801 seriousness

The BMW DTC U1801 should be addressed promptly as it can affect the communication and operation of critical control modules within the vehicle. Ignoring this DTC may lead to performance issues or potential safety concerns.

How to diagnose DTC U1801 on BMW

To diagnose the DTC U1801 on a BMW, follow these steps:

  1. Use a diagnostic scanner to retrieve the fault codes stored in the vehicle’s system
  2. Inspect the wiring and connectors between the Hybrid/EV Powertrain Control Module and the ECM
  3. Check for any visible signs of damage or corrosion
  4. Perform a communication test using a diagnostic tool to verify connectivity between the modules

How to fix DTC U1801 on BMW

To fix the BMW DTC U1801, consider the following steps:

  1. Repair or replace any damaged wiring or connectors in the communication network
  2. If the Hybrid/EV Powertrain Control Module is faulty, replace it with a new unit
  3. Ensure the Engine Control Module (ECM) is functioning correctly
  4. Clear the fault codes using a diagnostic scanner after the repairs

How to erase DTC U1801 on BMW

To erase the DTC U1801 on a BMW, follow these steps:

  1. Connect a diagnostic scanner to the vehicle’s OBD-II port
  2. Select the option to clear fault codes from the system
  3. Follow the on-screen prompts to erase the DTC U1801
  4. Verify that the code has been successfully cleared by rescanning the system

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

← All BMW Diagnostic Trouble Codes

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