BYD Sealion 7 1st generation airbag control unit repair

What is a BYD Sealion 7 1st generation airbag control unit?

In the BYD Sealion 7 1st generation, the airbag control unit, also called the SRS control unit, is the central control unit of the restraint system. It reads the signals from the crash sensors and, in an accident, decides within milliseconds which airbags and seatbelt pretensioners fire. After an accident it stores crash data and locks itself.

It is fitted in the BYD Sealion 7 1st generation (since 2025). It constantly monitors the connected sensors, squib circuits and wiring. If it detects a fault, the airbag warning light comes on in the instrument cluster.

As a driver, you will usually notice a problem through a warning light that no longer goes out, or through entries in the fault memory of the restraint system. These are indications, but not yet a finished diagnosis.

Why is the BYD Sealion 7 1st generation airbag control unit defective?

Most often the cause is crash data that remains in the unit after an accident, even in an accident where no airbags were deployed. Voltage spikes, cold solder joints, aged electronic components, and moisture and corrosion at the connectors are other possible causes.

Such data cannot be removed with an ordinary diagnostic tool. The control unit then stays locked, even though the vehicle itself may long since be intact again.

A failure is also possible without any accident history. Components age over the years, solder joints lose contact, and moisture causes corrosion on connectors. A jump-start or a discharged battery can lead to voltage spikes that put additional strain on the electronics.

Typical signs are an airbag warning light that stays on permanently, a fault memory that you cannot reset, and a diagnostic tool that cannot establish a connection to the unit.

Common error codes for BYD Sealion 7 1st generation airbag control unit repair

The error codes in the BYD Sealion 7 1st generation point to communication faults, internal faults of the control unit, problems with the voltage supply, squib circuits or stored crash data. Which of them appears depends on the specific damage.

The following codes are reported in the BYD Sealion 7 1st generation, among others:

• B16AE00 → Fault in the SRS control unit
• B17A000 → Internal fault of the control unit
• B17A200 → Stored crash data block recording
• B17A600 → Frontal impact detected in the crash data
• B17A800 → CAN bus communication interrupted
• B1694 → Supply voltage too low
• B1695 → Supply voltage too high
• B1600 → Driver front airbag not connected

Error codes are read out with a diagnostic tool. A code alone cannot reliably tell you that the control unit is defective; an airbag module or the wiring, for example at the connectors, can just as well be the cause. Only the inspection brings clarity.

What part numbers are available for the BYD Sealion 7 1st generation airbag control unit repair?

You read the part number from the label of the control unit in the BYD Sealion 7 1st generation. It determines the exact version, because depending on equipment and year of manufacture there are different numbers within one model series.

Enter the number printed on your label when you create the repair order. This establishes which version it is. Whether the unit is actually defective only becomes clear from reading out the fault memory or from the inspection.

The route to repair begins with having the fault memory read out. After that, you disconnect the battery, and only then do you remove the control unit. In the next step you create the repair order online, and finally you send in the unit.

Processing at Airbag24 usually takes 3–4 working days; during this time the unit is inspected, repaired and tested. The repaired control unit comes back with all vehicle data and is ready for use as soon as it is refitted — no coding or programming is required.