U1871 – BMW DTC

BMW DTC U1871 – Drive Motor ‘B’ Control Module Lost Communication With ECM via HS-CAN

DTC U1871 meaning on BMW

DTC U1871 on a BMW indicates that the Drive Motor ‘B’ Control Module has lost communication with the Engine Control Module (ECM) via the High-Speed Controller Area Network (HS-CAN) bus. This communication error can disrupt the proper functioning of the drive motor control system.

BMW DTC U1871 symptoms

Symptoms of DTC U1871 on a BMW may include:

  • Check Engine Light (CEL) illuminated
  • Reduced power or performance
  • Difficulty shifting gears
  • Vehicle may go into limp mode

BMW DTC U1871 causes

Possible causes of DTC U1871 on a BMW include:

  • Faulty Drive Motor ‘B’ Control Module
  • Wiring or connection issues between the control modules
  • ECM software or hardware issues

BMW DTC U1871 seriousness

DTC U1871 should be addressed promptly as it can lead to drivability issues and potential safety concerns. Ignoring this fault may result in further damage to the vehicle’s drive motor control system.

How to diagnose DTC U1871 on BMW

To diagnose DTC U1871 on a BMW, follow these steps:

  1. Use a diagnostic scanner to retrieve the fault codes
  2. Inspect the wiring and connections between the Drive Motor ‘B’ Control Module and ECM
  3. Check for any visible damage or corrosion in the wiring harness
  4. Perform a communication test between the modules using a diagnostic tool

How to fix DTC U1871 on BMW

To fix DTC U1871 on a BMW, consider the following:

  1. Repair or replace any damaged wiring or connectors
  2. If the Drive Motor ‘B’ Control Module is faulty, replace it with a new one
  3. Update the ECM software if necessary

How to erase DTC U1871 on BMW

To erase DTC U1871 on a BMW, use a diagnostic scanner to clear the fault codes stored in the system’s memory. After fixing the underlying issue, ensure that the repair is successful by performing a test drive and re-scanning for any remaining fault codes.