U1870 – BMW DTC

BMW DTC U1870 – Drive Motor ‘A’ Control Module Lost Communication With ECM via HS-CAN

DTC U1870 meaning on BMW

DTC U1870 on a BMW indicates that the Drive Motor ‘A’ 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 vehicle’s drive motor control system.

BMW DTC U1870 symptoms

Symptoms of DTC U1870 on a BMW may include:

• Check Engine Light (CEL) illuminated on the dashboard
• Loss of power or reduced performance
• Unusual noises coming from the drive motor
• Difficulty shifting gears

BMW DTC U1870 causes

The possible causes of DTC U1870 on a BMW include:

• Faulty Drive Motor ‘A’ Control Module
• Issues with the wiring or connectors between the control modules
• ECM software or hardware malfunctions
• Interference or communication bus issues

BMW DTC U1870 seriousness

DTC U1870 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 drive motor control system and other related components.

How to diagnose DTC U1870 on BMW

To diagnose DTC U1870 on a BMW, a mechanic would typically perform the following steps:

1. Use a diagnostic scanner to retrieve the fault codes and identify the specific module communication error
2. Inspect the wiring harness and connectors for any visible damage or corrosion
3. Check the control modules for proper power and ground connections
4. Perform a communication test between the affected modules to verify the issue

How to fix DTC U1870 on BMW

To fix DTC U1870 on a BMW, the following steps may be taken:

1. Repair or replace any damaged wiring or connectors in the communication network
2. Update the software of the affected control modules to the latest version
3. Reset the fault codes and perform a test drive to verify the repair
4. If the issue persists, further diagnosis may be required to pinpoint the exact cause

How to erase DTC U1870 on BMW

To erase DTC U1870 on a BMW, follow these steps:

1. Use a diagnostic scanner to clear the fault codes stored in the control modules
2. Perform a test drive to ensure the fault codes do not return
3. If the fault codes reappear, further diagnosis and repairs may be necessary

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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