150C airbag control unit fault

What does error code 150C indicate in the airbag control unit?

Error code 150C denotes a specific fault condition in airbag control units of the Citroën/Peugeot family, often associated with part number 150C. It signals a severe internal hardware defect or the presence of non‑erasable crash data, requiring professional electronic repair at the component level.

Technically, this error points to a malfunction within the control unit’s internal circuitry. This may involve defective SMD components such as voltage regulators, capacitors, or MOSFETs. As a result of the defect, the control unit can no longer ensure its safety functions, causing the SRS warning light to remain illuminated permanently.

An additional critical aspect is the storage of crash data after an accident. Once written, this data locks the control unit and prevents normal clearing of the fault memory via diagnostic tools. Resolving the issue requires direct intervention on the device’s memory chip.

How do you recognize error code 150C?

The typical symptoms of error code 150C are unmistakable and pose significant safety concerns. The primary indicator is a continuously or intermittently illuminated airbag or SRS warning light in the instrument cluster. Often, the control unit cannot be accessed by diagnostic equipment, or the error code remains unerased.

The most obvious sign is the persistently lit airbag warning light, alerting the driver that the entire restraint system is disabled and that, in the event of a crash, neither airbags nor seatbelt pretensioners would deploy.

Another clear symptom is the lack of communication with the control unit. When a workshop attempts to read the fault memory, it may receive no response from the airbag module, indicating a deep‑seated internal defect.

If crash data has been stored following an accident, error code 150C cannot be cleared using conventional methods. The control unit remains locked, even after all external airbag components have been replaced.

What causes error code 150C?

The main causes of error code 150C are almost exclusively found at the hardware level of the control unit. These include internal electronic faults due to aging components, stored crash data after an accident, corrosion damage caused by moisture ingress, or electrical disturbances such as overvoltage.

Internal electronic faults are the most common cause. Defective SMD components—such as voltage regulators, capacitors, resistors, or processors—can disrupt proper board functionality and trigger the error.

Stored crash data following an activation event represents another key cause. After an accident, the control unit self‑locks to prevent reuse without proper inspection. This lock can only be lifted through specialized repair procedures.

Corrosion resulting from moisture ingress can lead to short circuits or damaged traces on the circuit board. Leaky seals in the vehicle are often responsible for such water damage to the control unit.

Overvoltage—caused, for example, by faulty jump-starts—or consistently low battery voltage can also harm the control unit’s sensitive electronics and give rise to this error code.

In rarer cases, issues with external wiring, defective connectors, or disruptions on the CAN bus may interrupt communication with the control unit and result in secondary errors.

On which vehicles does error code 150C occur?

Error code 150C is specific to certain models within the PSA Group. It primarily affects Citroën vehicles, especially various versions of the Saxo compact car. Repair is feasible and economically viable for these particular control units.

At Airbag24, we repair error code 150C for the following models:

Citroën Saxo I (model years 1996–1999)

Citroën Saxo I Facelift (model years 1999–2003)

Citroën Saxo VTS I

How is error code 150C professionally repaired?

Repairing error code 150C involves a multi‑step technical process. Upon submission to Airbag24, a detailed electronic analysis is performed, followed by the repair of defective components on the circuit board and the deletion of any stored crash data. A final functional test ensures full operability.

Before removal, the fault memory should be read and documented on the vehicle to confirm error code 150C. The control unit must then be securely packaged and sent to the repair facility along with the fault report.

Upon receipt at Airbag24, the housing is opened and a visual inspection is performed for corrosion or fire damage. This is followed by electronic fault analysis, during which supply voltages and signal paths on the circuit board are measured to identify defective SMD components such as voltage regulators or processors.

Identified faulty components are carefully desoldered and replaced with new, high-quality parts. Damaged traces or ground connections are repaired. If crash data is available, it is analyzed and erased using specialized hardware and software.

Following hardware repair, the control unit’s correct software coding is restored if necessary. A final system test on the test bench simulates the vehicle environment and verifies the proper functioning of all circuits and correct communication.

We provide a 12-month warranty on all repairs. After successful testing, the control unit is returned to you ready for installation.