Toyota Proace Max airbag control unit repair

What is a Toyota Proace Max airbag control unit?

In a crash, the airbag control unit in the Toyota Proace Max makes the deployment decision: it is the central control unit of the restraint system (SRS) and determines which airbags and seatbelt pretensioners fire. To do this, it evaluates the signals from the crash sensors.

In an emergency the unit has only milliseconds. It assesses the incoming sensor signals, detects the severity of the impact and selectively releases the restraints that are needed in that situation. In the Toyota Proace Max (since 2024) it performs this task for the entire system.

Outside an accident, however, it is not idle. During every journey it monitors the connected components and indicates a detected fault via the airbag warning light in the instrument cluster. After an accident it stores crash data and locks itself.

Why is the Toyota Proace Max airbag control unit defective?

The cause is usually crash data stored after an accident, even if no airbag deployed. Other causes include aged electronic components, cold solder joints, moisture with corrosion on connectors, and voltage spikes.

Stored crash data cannot be removed with an ordinary diagnostic tool. That is why the warning light stays on even when the bodywork and airbag modules are long since back in order.

Voltage spikes can be caused, for example, by a weak battery or jump-starting. If moisture gets into connectors, corrosion forms there. Over the years, components and solder joints on the circuit board also age.

A defect usually shows itself like this: the airbag warning light stays on permanently, the fault memory cannot be cleared, or the diagnostic tool cannot establish a connection to the control unit.

Common error codes for Toyota Proace Max airbag control unit repair

In the Toyota Proace Max, the error codes of the airbag control unit report internal faults, interrupted communication, faulty firing circuits or occupant classification problems. The code tells you in which part of the system the control unit has detected the deviation.

Among others, the following error codes are known for this vehicle:

• B1000 → Internal fault in the airbag control unit
• B1100 → Internal fault in the airbag sensor unit
• U0151 → Communication with the airbag control unit lost
• B1800 → Fault in the driver airbag firing circuit
• B1805 → Fault in the passenger airbag firing circuit
• B1650 → Occupant classification fault

Error codes are read out with a diagnostic tool. A single code does not prove, however, that the control unit is defective: the cause may equally be a connector, wiring or an airbag module. Only testing shows where the fault lies.

What part numbers are available for the Toyota Proace Max airbag control unit repair?

You will find the part number on the label of the Toyota Proace Max airbag control unit. It specifies the exact version, because a model series has different numbers depending on equipment and year of manufacture.

We do not yet have a part number for this model. Please read the number yourself from the label of the removed unit and enter it in the repair order.

The number only tells you which version it is. Whether the unit is actually defective is only established by reading out the fault memory or by testing.

The route to repair: first have the fault memory read out. Then disconnect the battery and remove the control unit. Next, create a repair order online and send in the unit. Testing, repairing and checking at Airbag24 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.