BYD Atto 2 1. Generation DM-i airbag control unit repair

What is a BYD Atto 2 1. Generation DM-i airbag control unit?

The airbag control unit is the central control unit of the restraint system (SRS) in the BYD Atto 2 1. Generation DM-i. It monitors the system continuously, evaluates the signals from the crash sensors and, in an accident, decides within milliseconds which airbags and seatbelt pretensioners to deploy. It reports faults via the airbag warning light.

In everyday use you will notice little of this: when the ignition is switched on, the control unit runs a self-test, and the airbag warning light goes out again after a short time. If it stays on, the system has detected a fault. The control unit is fitted in the BYD Atto 2 1. Generation DM-i (since 2025).

It also keeps checking the sensors, the squib circuits and the power supply while you drive. After an accident the control unit stores crash data and locks itself.

Why is the BYD Atto 2 1. Generation DM-i airbag control unit defective?

The most common cause is crash data stored in the airbag control unit after an accident, even if no airbag deployed. Other causes are aged electronic components, cold solder joints, moisture and corrosion on connectors, and voltage spikes. A standard diagnostic tool cannot erase stored crash data.

Voltage spikes arise, for example, from a weak battery or from jump-starting. They can stress sensitive components in the BYD control unit. Over the years solder joints and electronic components also age, and moisture can attack the contacts on the connectors.

Typical signs are an airbag warning light that stays on permanently, a fault memory that cannot be cleared, or a diagnostic tool that cannot connect to the control unit. In all of these cases it is worth having the control unit tested.

Common error codes for BYD Atto 2 1. Generation DM-i airbag control unit repair

The error codes on the BYD Atto 2 1. Generation DM-i indicate internal control unit faults, communication problems on the data bus, deviations in the supply voltage or stored crash data. An airbag module that is not connected is also reported as a code.

The following list shows codes that can occur on this model:

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

Error codes are read out of the fault memory with a diagnostic tool. A code alone does not reliably show that the control unit is defective: connectors, wiring or an airbag module can also be the cause. Only testing shows where the fault actually lies.

What part numbers are available for the BYD Atto 2 1. Generation DM-i airbag control unit repair?

The part number is printed on the label of the control unit and determines the exact version. Within a model series there are different numbers depending on equipment and year of manufacture, so it is worth checking the label before you send the unit in.

Read the number from the label on your unit and enter it in the repair order. Whether the unit is defective is only shown by reading out the fault memory or by testing it.

This is how you get to the repair: first have the fault memory read out, disconnect the battery and remove the control unit. Then create a repair order online and send in the unit. Processing at Airbag24, including testing, repairing and checking, usually takes 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.