BYD Tang 2nd generation airbag control unit repair

What is a BYD Tang 2nd generation airbag control unit?

Inside the BYD Tang 2nd generation, the airbag control unit is the central unit of the restraint system (SRS). It registers an impact via the crash sensors and decides within milliseconds which airbags and seatbelt pretensioners fire.

The unit is installed in the BYD Tang 2nd generation (since 2018). Its work begins long before an emergency: as soon as the ignition is switched on, it monitors the entire restraint system and indicates faults via the airbag warning light in the instrument cluster.

The readings from the crash sensors constantly flow into it. Only if they point to a severe impact does it trigger the squib circuits of the affected airbags and seatbelt pretensioners. If the vehicle has been in an accident, the unit stores crash data and locks itself.

Why is the BYD Tang 2nd generation airbag control unit defective?

The most common cause is an accident: crash data stored in the process remain in the BYD Tang 2nd generation airbag control unit even if no airbag deployed. Other possible causes include aged electronic components, cold solder joints, moisture and corrosion on connectors, and voltage spikes.

A normal diagnostic tool cannot remove this crash data. The control unit therefore keeps reporting a fault, although airbags, seatbelt pretensioners and wiring may be undamaged.

Voltage spikes occur, for example, with a weak battery or when jump-starting. If moisture enters the vehicle, connectors corrode and lose their reliable contact. On top of that comes the passage of time: solder joints and electronic components age and eventually fail.

How you notice it: the airbag warning light stays on permanently, the fault memory remains filled despite attempts to clear it, or the diagnostic tool cannot access the control unit.

Common error codes for BYD Tang 2nd generation airbag control unit repair

The codes for the BYD Tang 2nd generation point to quite different faults: internal faults in the control unit, interrupted communication in the vehicle network, a supply voltage that is too high or too low, an airbag that is not connected, and crash data.

These codes appear on this vehicle, and they give a first indication for troubleshooting:

• B16AE00 → Fault in the SRS control unit
• B17A000 → Internal control unit fault
• B17A200 → Crash record is locked or stored
• B17A600 → Frontal impact detected in the control unit
• 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 single entry does not prove that the control unit is defective, as connectors, wiring or an airbag module can equally be the cause. Only the inspection shows what the actual cause is.

What part numbers are available for the BYD Tang 2nd generation airbag control unit repair?

For the BYD Tang 2nd generation airbag control unit, read the part number from the label on the unit. It determines the exact version, since equipment and year of manufacture lead to different numbers within a model series.

We currently have no part numbers on file for this vehicle. Please note the number yourself from the label of the removed unit and enter it in the repair order. This way your unit is matched unambiguously.

First have the fault memory read out, because only reading it out and the subsequent inspection show whether the unit is really defective. Then disconnect the battery and remove the control unit. Next, create a repair order online, and finally send your unit to us. Inspecting, repairing and testing usually take 3–4 working days at Airbag24.

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.