U0402 – BMW DTC

BMW DTC U0402 – Invalid Data Received From Transmission Control Module

DTC U0402 meaning on BMW

DTC U0402 on a BMW indicates that the Engine Control Module (ECM) has detected invalid data from the Transmission Control Module (TCM). This means that the communication between the ECM and TCM is not functioning properly, leading to potential issues with the transmission system.

BMW DTC U0402 symptoms

Symptoms of DTC U0402 on a BMW may include:

  • Check Engine Light (CEL) illuminated
  • Transmission shifting issues
  • Reduced fuel efficiency
  • Vehicle may go into limp mode

BMW DTC U0402 causes

Common causes of DTC U0402 on a BMW include:

  • Faulty wiring or connectors in the communication network
  • Defective TCM or ECM
  • Software issues
  • Interference from aftermarket electronic devices

BMW DTC U0402 seriousness

DTC U0402 should not be ignored as it can lead to potential transmission problems and affect the overall drivability of the vehicle. It is important to address this issue promptly to prevent further damage.

How to diagnose DTC U0402 on BMW

To diagnose DTC U0402 on a BMW, you can:

  • Use a diagnostic scanner to retrieve the fault codes
  • Inspect the wiring and connectors for any visible damage
  • Check for any software updates available for the ECM and TCM
  • Perform a communication test between the ECM and TCM

How to fix DTC U0402 on BMW

To fix DTC U0402 on a BMW, you may need to:

  • Repair or replace any damaged wiring or connectors
  • Update the software in the ECM and TCM
  • Replace the TCM or ECM if found to be faulty
  • Ensure there is no interference from aftermarket electronic devices

How to erase DTC U0402 on BMW

To erase DTC U0402 on a BMW, you can:

  • Use a diagnostic scanner to clear the fault codes
  • After fixing the underlying issue, perform a test drive to ensure the code does not return

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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