Skip to content
English
  • There are no suggestions because the search field is empty.

Bosch MED17.7.5 - TC1793

Bosch MED17.7.5 - TC1793 FAQ | bFlash Technical Support

Bosch MED17.7.5 - TC1793

Errors

Quickly identify and resolve common communication and security issues related to the Bosch MED17.7.5 control unit.

[UART_CAN API] Failed to read ISO14230 length byte

A communication error often caused by physical wiring gaps or incorrect CAN pin connections.

View Solution →

7F-80-33 / 7F-80-12

Security restriction on Bosch 2021+ ECUs that prevents the use of BENCH mode for programming.

View Solution →

Concerns vehicles from

Aston Martin Mercedes-Benz

[UART_CAN API] Failed to read ISO14230 length byte : [UART_CAN API] No data to read : TSW SendKey RX error

Method: BENCH

Issue: The bFlash tool is unable to establish a stable communication link with the ECU via the CAN interface during a BENCH session.

Solution
  • Perform a thorough check of your wiring harness and physical pins.
  • Ensure there is no physical gap or loose contact on the CAN High and CAN Low pins.
  • Verify that the power supply to the ECU is stable and meets the required voltage.
  • If the problem persists, try reseating the BENCH cable connectors.
To understand more

This error code essentially points to a hardware communication timeout. The "No data to read" message indicates that while the tool is sending requests, it is receiving no response from the TC1793 processor. This is almost exclusively caused by physical connection issues on the CAN bus pins.

7F-80-33 / 7F-80-12

Method: BENCH / Recovery: OBD

Issue: You are attempting to access a newer generation Bosch ECU (2021+) that has manufacturer-level security blocking BENCH protocol access.

Solution
  • For Mercedes-Benz vehicles, switch the programming method to OBD, which remains fully functional even on 2021+ models.
  • Be aware: Programming via VR (Virtual Read) will overwrite any existing non-original tuning with the original calibration.
  • If you are working on an Aston Martin or another brand and encounter this code, Contact our technical support.
To understand more

Starting in 2021, Bosch implemented updated security certificates that specifically disable the BENCH access point used by many tuning tools. While BENCH is restricted, OBD programming typically remains accessible because it uses different diagnostic service entries that have not been restricted in the same way by the manufacturer.