B1007: Diagnosis Sensor Unit Fault

Circuit fault

What B1007 means

Nissan builds the crash sensing accelerometer and the diagnostic electronics into one assembly, usually mounted on the floor tunnel under the console. That assembly monitors every squib circuit, makes the deployment decision, and diagnoses itself. B1007 is stored when something in that unit or its immediate circuits is reported as faulty.

Because the definition is broad, the useful next step is reading the rest of the code set and the live data rather than reacting to this code alone. A unit reporting a fault after a deployment is a different situation from one reporting a fault on a car that has never been hit, and voltage supply problems can produce unit faults on hardware that is otherwise sound.

Common causes

• An internal failure inside the diagnosis sensor unit
• Low system voltage or a weak battery affecting the unit self tests
• Poor ground or a loose mounting that leaves the unit unable to read body motion
• Water damage from a leak at the floor pan or console area
• A unit that locked itself out after an airbag deployment
• A used unit installed from another vehicle that still carries stored faults

Crash data or hardware fault?

Where a plain squib code tracks one loop, this one concerns the unit that does the monitoring, and it can present as a live fault or as a stored condition. Crash data is always the stored kind: written once at deployment, held permanently in the unit, and cleared only by a module reset rather than by any repair on the car.

Does our reset clear it?

If the unit is locked after a deployment or holding stored faults, our mail in reset is the service that brings it back, and it goes after the airbags, belts, and sensors on the vehicle have been replaced. If the unit has genuinely failed internally, a reset will not recover it and it needs replacing. Send it in or call 501-988-0611 and we will tell you which of those you are dealing with.

Which makes throw it

B1007 appears under Nissan, and diagnosis sensor unit is their own name for the airbag control module assembly. Other makes call the same part by different names, so the term is worth knowing when reading Nissan service information.

What to do next

Test the battery and charging system before anything else, because low voltage produces unit faults on healthy hardware and is the cheapest thing on the list to rule out. Confirm the unit mounting bolts are tight and the grounds are clean, since the accelerometer inside needs a solid connection to the body. Check for water at the console and floor. Then mail us the unit for evaluation and a reset if the fault is stored rather than a hardware failure. Related codes: B1001, B1015, B1349.