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Siemens Simos18.10 - TC1791

Siemens Simos18.10 - TC1791 | bFlash FAQ

Siemens Simos18.10 - TC1791

Errors

Quick reference guide for common issues encountered while tuning or diagnosticating the Simos18.10 ECU.

ECU Type unknown/ Error

This error occurs when the bFlash server does not yet have your specific software version mapped for OBD operations.

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71-01-02-02-01

A protocol conflict triggered by the presence of a third-party patch or existing tuning on the control unit.

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No data to read : UDS CheckProgrammingPreconditions RX error

Communication failure often caused by insufficient battery voltage or electronic interference during the pre-programming check.

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Concerns vehicles from

Audi Porsche Seat Skoda Volkswagen

ECU Type unknown/ Error

Method: OBD / Recovery: BOOT

Issue: The bFlash software is unable to identify your specific ECU variant via the standard OBD protocol.

Solution
  • Switch to a BOOT mode reading for this ECU.
  • Extract the full internal data from the TC1791 microcontroller.
  • Send the resulting file to the bFlash team for mapping.
To understand more

This happens because your specific software version is not yet available in our online database. A BOOT reading is necessary to obtain the full binary content, which allows our team to create the appropriate mapping for future OBD use.

71-01-02-02-01

Method: OBD & BENCH

Issue: The ECU rejects the connection attempt because it detects a non-standard software state.

Solution
  • Identify if the ECU has been previously tuned or patched by another tool.
  • Restore the ECU to its Original (Stock) data before attempting to write with bFlash.
  • Ensure all TPROT or security patches from previous tools are removed.
To understand more

This error is typically a security response from the Siemens Simos firmware. When the software has been modified or "patched" by other devices, the communication protocols may be altered, preventing bFlash from establishing a secure link until the original file is restored.

No data to read : UDS CheckProgrammingPreconditions RX error

Method: OBD

Issue: The vehicle's electronic system is not meeting the necessary safety criteria to begin the reading/writing process.

Solution
  • Open the vehicle's hood (often a required hardware signal for VAG Group cars).
  • Connect a high-quality battery charger/stabilizer to maintain stable voltage.
  • Ensure no other high-consumption devices (fans, lights) are active.
  • If the error persists: Contact our technical support with a log file.
To understand more

The UDS protocol performs a safety check called "Programming Preconditions" before allowing any changes. Low voltage or a closed hood can trigger a failure signal from the Gateway (SGW), causing the software to abort for safety reasons.