BMW DTC U049B – Invalid Data Received from Tachograph Module
DTC U049B meaning on BMW
DTC U049B on a BMW indicates that the Engine Control Module (ECM) has detected invalid data being received from the Tachograph Module. The Tachograph Module is responsible for recording and storing data related to the vehicle’s speed and distance traveled. When the ECM receives data that is inconsistent or incorrect from the Tachograph Module, it triggers the U049B diagnostic trouble code.
BMW DTC U049B symptoms
Symptoms of DTC U049B on a BMW may include:
- Check Engine Light illuminated
- Inaccurate speedometer readings
- Issues with cruise control functionality
- Possible loss of communication with the Tachograph Module
BMW DTC U049B causes
The common causes of DTC U049B on a BMW include:
- Faulty Tachograph Module
- Wiring or connection issues between the Tachograph Module and ECM
- Software or programming errors
BMW DTC U049B seriousness
While DTC U049B may not directly affect the drivability of the vehicle, it is important to address this issue promptly. Ignoring the problem can lead to inaccurate data being recorded and potential issues with vehicle performance monitoring systems.
How to diagnose DTC U049B on BMW
To diagnose DTC U049B on a BMW, follow these steps:
- Use a diagnostic scanner to retrieve the fault codes stored in the ECM.
- Inspect the wiring and connections between the Tachograph Module and ECM for any damage or corrosion.
- Check the Tachograph Module for proper functionality and communication.
- Perform a software update or reprogramming if necessary.
How to fix DTC U049B on BMW
To fix DTC U049B on a BMW, consider the following:
- Replace the faulty Tachograph Module if it is determined to be the cause of the issue.
- Repair any damaged wiring or connections between the Tachograph Module and ECM.
- Update the software or reprogram the ECM to ensure proper communication.
How to erase DTC U049B on BMW
To erase DTC U049B on a BMW, you can use a diagnostic scanner to clear the fault codes stored in the ECM. After addressing the underlying issue that caused the fault code, clearing the code will reset the Check Engine Light and ensure that the system is functioning properly.
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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