B0055 00 airbag control unit fault

What does error code B0055 00 mean?

Error code B0055 00 indicates a stored deployment condition, typically “Side Airbag Deployment Commanded.” After a side impact or an event interpreted as such, the airbag control unit permanently stores crash data and enters a locked state. This is a safety measure that requires professional inspection and reset.

Technically, this means the control unit (ECU) has issued a command to deploy a side airbag. This information is saved in a non-volatile memory area (EEPROM or Flash) and cannot be erased by a standard diagnostic tool. The system switches to a safety mode to prevent unintended deployments after an accident.

In rarer cases, the code may also point to an internal hardware fault within the control unit itself, triggering a similar lockout. In either case, the entire airbag system remains deactivated until the issue is professionally resolved.

How can you recognize error code B0055 00?

The primary and unmistakable symptom of error code B0055 00 is the continuously illuminated airbag warning light on the instrument panel. Additionally, diagnostic tools may fail to establish communication with the airbag control unit altogether or only achieve limited connectivity, as it remains in a locked state.

The airbag warning light does not turn off after starting the vehicle, signaling to the driver that the entire passive safety system (SRS – Supplemental Restraint System) is inoperable and would not deploy airbags in the event of another accident.

When attempting to read the fault memory with a standard workshop scanner, error code B0055 00 appears as permanent or non-erasable. Any attempts to clear it fail because the stored crash data requires a specialized reset procedure.

Why does error code B0055 00 occur?

The most common cause of error code B0055 00 is crash data stored in the control unit following a side impact. Other potential causes include internal electronic faults such as damaged components, corrosion, or memory errors (EEPROM/Flash corruption). Improper repair attempts can also lead to this error pattern.

Stored crash data is the primary culprit. The control unit performs its function by permanently saving deployment information after a collision and then locking itself. This state must be deliberately reset by a qualified service provider.

An internal electronic fault is another possibility. This includes damaged circuit traces, defective SMD components (e.g., drivers, MOSFETs, voltage regulators), cold solder joints caused by aging or vibrations, and corrosion due to moisture ingress.

Memory errors in EEPROM or Flash chips can also trigger the error. Data corruption in these memories causes the control unit to lose its configuration or enter an undefined safe state, which is interpreted as an internal fault.

Which vehicles experience error code B0055 00?

Error code B0055 00 primarily affects vehicles from the General Motors (GM) group, including brands like Chevrolet, Hummer, Pontiac, Saab, and Saturn—especially models from the early 2000s through today. The exact definition of the error may vary slightly depending on the model and year of manufacture.

At Airbag24, we repair error code B0055 00 for numerous models across these brands. Examples include:

Chevrolet: Corvette (C1, C3), Tahoe (5th Gen), Colorado (1st Gen), Epica (1st & 2nd Gen), Matiz (1st & 3rd Gen), City Express (1st Gen), and Camaro ZL1 (5th & 6th Gen).

Hummer & Pontiac: Hummer HMMWV M1135, Pontiac Montana (including Extended), Pontiac 6000 A-Body, and Pontiac Fiero Base.

Saab & Saturn: Saab 9000 CSE, Saab 9-4X Aero, and Saturn LW LW1.

How is error code B0055 00 repaired?

A professional repair begins with diagnosing the removed control unit. Depending on the findings, either only the stored crash data is erased using specialized programming tools, or the circuit board undergoes electronic refurbishment. The unit is then thoroughly tested for proper functionality and returned with 2 years' statutory liability for defects.

Before removal, the fault memory should be read out, and the resulting log attached to the unit when sending it to Airbag24. This helps our technicians perform quick and precise fault analysis.

Upon receipt, a detailed inspection takes place, including visual checks for physical damage and electrical measurements of supply voltages and relevant components. Based on these results, it is determined whether memory clearing alone suffices or a more extensive circuit board repair is required.

During repair, either the crash data in the memory is professionally and securely reset, or defective electronic components such as capacitors, driver ICs, or voltage regulators are replaced with high-quality aftermarket parts. All work is performed by experienced technicians.

Finally, each repaired control unit undergoes a functional test on a specialized test bench. Here, communication with a diagnostic tool and the correct behavior of simulated sensors are verified. We provide 2 years' statutory liability for defects on all repairs.