B1015: Diagnosis Sensor Unit

Often a hardware fault

What B1015 means

Nissan and Infiniti use the term air bag diagnosis sensor unit for the brain of the restraint system. That unit watches the driver and passenger airbags, the side and curtain airbags, the pretensioners, and the occupant classification system, and it carries the crash sensors and a backup power supply. B1015 is the code it sets when it detects a problem in that monitoring, which can be inside the unit itself or in what it is watching.

Because the diagnosis sensor unit is the module, B1015 frequently points to an internal fault inside that unit. The airbag warning light comes on or flashes, and the system flags that it can no longer vouch for itself.

Common causes

• An internal fault inside the diagnosis sensor unit
• A sensor or circuit the unit monitors reading out of range
• Low or unstable supply voltage corrupting the unit's self-test
• Connector or harness corrosion between the unit and an SRS component

Crash data or hardware fault?

B1015 leans toward hardware. It is the module reporting a malfunction in the restraint system or in itself, which sets it apart from a clean stored deployment record like B0051 or B1193. That matters, because a reset clears stored data while a failed part still needs repair. The honest path is to read the code carefully and check supply voltage and connectors before deciding the unit itself is bad.

Does our reset clear it?

It depends on what set it. If B1015 followed a deployment and there is stored crash data behind it, our airbag module reset can clear that. If it is a live internal fault, the unit needs repair or replacement to clear for good. Send us the unit and we will test it and tell you which it is. You only pay when a reset actually holds.

Which makes throw it

B1015 is specific to Nissan and Infiniti, tied to their diagnosis sensor unit naming. Common on Altima, Sentra, Rogue, Maxima, and the Infiniti G and Q lines.

What to do next

Confirm the battery and charging system are healthy and the unit's connectors are clean, since voltage and connection issues can mimic an internal fault. Then send us the diagnosis sensor unit for testing. Related codes: B1620 (module internal fault), B1916 (airbag circuit fault), and B1000 (airbag ECU malfunction).