BYD Seal 1st generation airbag control unit repair

What is a BYD Seal 1st generation airbag control unit?

In the BYD Seal 1st generation, the airbag control unit is the central control unit of the restraint system (SRS). It receives the signals from the crash sensors and, in an accident, decides within milliseconds which airbags and seatbelt pretensioners deploy. At the same time it monitors the system continuously and indicates faults via the airbag warning light.

The control unit is fitted in the BYD Seal 1st generation (since 2023). To work reliably, it must constantly know whether sensors, squib circuits and power supply respond as intended. If one of these responses fails, it detects this and switches on the warning light.

If an accident occurs, the control unit stores crash data and locks itself.

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

The cause is usually crash data that was stored in the BYD Seal 1st generation control unit after an accident, even if no airbag deployed. Other possible causes are aged electronic components, cold solder joints, moisture with corrosion on connectors and voltage spikes, for example with a weak battery or after jump-starting.

An ordinary diagnostic tool cannot remove such crash data. The fault therefore remains, even if you reset the fault memory repeatedly.

A failure usually shows itself like this: the airbag warning light stays on permanently, the fault memory cannot be cleared, or the diagnostic tool finds no connection to the control unit. A defective control unit does not mean, by the way, that an airbag has deployed. Electronics age even without an accident, and moisture can attack contacts. What applies in an individual case is only clarified by the inspection.

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

The error codes in the BYD Seal 1st generation point to different areas of the restraint system: to communication in the vehicle network, to internal faults of the control unit, to the power supply, to squib circuits or to stored crash data. Which area is affected can be read from the respective code.

A code can therefore concern the control unit itself, but equally wiring, connectors, the power supply or a connected airbag module. The following codes are known for this vehicle:

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

The path to a diagnosis begins with reading out the fault memory using a diagnostic tool. A single code, however, does not yet prove that the control unit is defective, because connectors, wiring or an airbag module can just as well be the trigger. Only the inspection provides clarity.

Write down the codes that were read out or save the log, and send it in with the unit. This helps to narrow down the fault.

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

You will find the part number on the label of the control unit in the BYD Seal 1st generation. It determines the exact version, because depending on equipment and year of manufacture, different numbers are in circulation within one model series.

Look at the label of your removed unit, take over the number and enter it in the repair order. This is how the matching version is assigned. Whether the unit is actually defective only becomes clear by reading out the fault memory or through the inspection.

The process up to the repair: first have the fault memory read out and disconnect the battery. Then remove the control unit, create a repair order online and send the unit in. At Airbag24, inspecting, repairing and testing usually take 3–4 working days. 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.