BYD Dolphin 1st generation airbag control unit repair

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

The BYD Dolphin 1st generation airbag control unit is the central control unit of the restraint system (SRS). It evaluates the signals from the crash sensors, decides within milliseconds in an accident which airbags and seatbelt pretensioners deploy, and reports faults via the airbag warning light.

In everyday use, the airbag control unit only makes itself noticed through the warning light: it runs a self-test at every start and then monitors the system continuously. In the BYD Dolphin 1st generation (since 2023) it is installed as the central unit of the restraint system. Squib circuits, sensors and wiring are continuously monitored for faults. If the control unit detects a malfunction, it shows this via the airbag warning light in the instrument cluster.

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

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

The most common cause is crash data stored after an accident, even if no airbag deployed; a normal diagnostic tool cannot erase it. Other causes are aged electronic components, cold solder joints, moisture and corrosion on connectors, and voltage spikes.

Voltage spikes arise, for example, from a weak battery or from jump-starting. Moisture can cause corrosion on connectors. Cold solder joints and aged components lead over time to intermittent faults or to complete failure of the unit.

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. With any of these signs, it is worth having the unit tested.

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

The error codes for the BYD Dolphin 1st generation airbag control unit point to different types of fault. The codes indicate internal control unit faults, communication faults on the data bus, power supply problems, airbag modules that are not connected, and the detection of an accident.

This selection shows error codes that occur in connection with this control unit:

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

Error codes are read out 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 lies.

What part numbers are available for the BYD Dolphin 1st generation 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 you should know the number of your unit.

This list gives known part numbers for this control unit; it is not complete:

• EM2E-3658100

Compare the number on your unit with this list. This only confirms that it is the right unit. Whether it is defective is shown only by reading out the fault memory or by testing.

Here is how to proceed: first have the fault memory read out. Then disconnect the battery and remove the control unit. Create a repair order online and send in the unit. Processing at Airbag24 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.