B1118: Left Satellite Sensor Failure

Hardware fault

What B1118 means

The left satellite sensor feeds the control unit acceleration data from the driver side of the vehicle. It is mounted out at the structure, not inside the module, so it sees an impact earlier than the module does. B1118 sets when that sensor fails its own diagnostic or stops returning a usable signal, and the module cannot make a firing decision without it.

Sensor failure and wiring failure look identical from the driver seat, since both end with the same warning light. The difference shows up at the connector. A sensor that answers with bad data has failed internally. A sensor that never answers at all can be a broken wire, a pin pushed out of the connector body, or a supply the module is no longer providing.

Common causes

• Internal failure of the left satellite sensor after age, heat, or vibration
• A sensor reused after a left side impact that already stressed it
• Broken or pinched harness between the left sensor and the control unit
• A connector lock that was never seated during door, fender, or rocker panel work
• Corrosion at the left sill or footwell from a leaking door seal or windshield

Crash data or hardware fault?

Infiniti files B1118 as a hardware fault, so it describes a part condition rather than a crash event. Deployment data is stored separately and permanently. If the vehicle has both, clearing the sensor fault and clearing crash data are two different jobs, and only the crash data requires the module to come out of the car.

Does our reset clear it?

Our mail-in reset returns the control unit to a clean factory state and removes B1118 from stored memory. It does not repair a bad sensor. If the left satellite sensor is still failing when the module goes back in, the light comes back on the first key cycle. Test the sensor and its wiring before you rely on the reset.

Which makes throw it

B1118 comes up on Infiniti lookups. If you are working a Nissan built on the same restraint architecture, inspect the left satellite sensor the same way, though the code number it stores may not match.

What to do next

Start with a visual check at the left sensor: connector fully latched, pins straight, no green on the terminals. Look for water staining on the carpet below it, since a wet footwell explains a lot of left side sensor codes. If the wiring checks out end to end, replace the sensor with a genuine OEM unit and confirm the light goes out before you call it finished. Related codes: B1113, B1121, B1BA8.