B1855 airbag control unit fault

What does error code B1855 mean?

Error code B1855 indicates a critical EEPROM read error in the airbag control unit. This hardware-related fault occurs when the control unit can no longer reliably read or write data due to issues with the non-volatile memory (EEPROM). The built-in self-diagnosis detects this memory access error and triggers a system warning.

Technically, the EEPROM memory chip is responsible for storing system-relevant data, including configuration and crash data. A read error at this fundamental level prevents the entire airbag system from functioning correctly.

The control unit identifies this internal fault through continuous self-monitoring and stores error code B1855 in the fault memory to enable targeted diagnostics.

What symptoms indicate error B1855?

The primary and unmistakable symptom of error code B1855 is the permanently illuminated or flashing airbag warning light on the dashboard. This warning signal informs the driver of a serious malfunction in the restraint system and suggests that the airbags might not deploy in the event of a crash.

Once the control unit’s self-diagnosis detects the EEPROM error, the warning light activates. It will not extinguish even after restarting the vehicle as long as the hardware defect persists in the memory chip or its control circuitry.

What are the technical causes of error code B1855?

The main cause of error B1855 lies in the electronic memory technology of the control unit itself. Physical damage—such as water ingress, corroded EEPROM chips, or damaged traces on the circuit board—is often responsible for failure. Problems with the power supply or internal communication between the processor and the memory chip can also trigger this error.

A common cause is moisture entering the control unit. Water can lead to short circuits on the circuit board and permanently damage sensitive memory components or traces.

Aging-related defects in EEPROM chips or corrosion at solder joints are also typical triggers. In rarer cases, malfunctions in the control unit’s internal power supply may impair proper memory operation.

Which vehicles are affected by B1855?

Error code B1855 frequently occurs in specific vehicle generations where the memory technology used is prone to defects. In particular, the Toyota Camry XV10 model series from 1991 to 1996 is well-known for this specific EEPROM error. Airbag24 specializes in repairing these control units.

At Airbag24, error code B1855 is specifically repaired for the following models: Toyota Camry series XV10 (model years 1991–1996).

How is error B1855 professionally repaired?

A professional repair of error B1855 at Airbag24 follows a proven electronic restoration process. After a thorough diagnosis, all crash data stored in the EEPROM is first erased. Defective components, such as memory chips or traces, are then repaired or replaced, and the control unit is reprogrammed for the vehicle.

In the first step, the control unit undergoes a visual inspection, and the fault memory is read out to confirm error B1855 unequivocally.

Using specialized software, existing crash data stored in the EEPROM after an accident is irreversibly deleted. This step is essential to restore full functionality to the control unit.

Defective memory chips or damaged traces on the circuit board are repaired or replaced at the component level. Subsequently, the control unit is recoded and reset to factory settings to ensure flawless operation in the vehicle.

Airbag24 provides 2 years' statutory liability for defects on every repair performed.

Repair or replacement: Which is the better solution for B1855?

Electronically repairing an airbag control unit with error B1855 is clearly preferable to purchasing a new one. Not only is it significantly more cost-effective, but it also offers a sustainable and time-efficient solution. Rather than buying an expensive new part, the original unit is expertly refurbished and remains installed in the vehicle.

A new control unit from the manufacturer often comes with very high costs. Repairing the unit provides substantial savings while restoring the original part’s full functionality.

Specialized workshops possess the necessary diagnostic and repair equipment, along with experience gained from thousands of repairs, enabling them to reliably and durably resolve even complex electronic faults like B1855.