The dreaded B00A0 error code on your Nissan can trigger the airbag warning light, often leading to a costly dealership repair. This code signifies an issue with the Occupant Classification System Sensor Unit, responsible for detecting passengers in the front seat and adjusting airbag deployment accordingly. Dealerships often recommend replacing the entire seat base, a time-consuming and expensive solution. However, this guide outlines a more affordable DIY fix for the B00a0 Nissan error, focusing on replacing the faulty sensor.
This guide provides a step-by-step solution to replace the occupant classification sensor in a 2018 Infiniti Q60, which utilizes the same sensor (part number 98853-3JA0A) as many Nissan models. This approach offers a significant cost saving compared to the dealership’s recommendation of a complete seat base replacement.
Replacing the Occupant Classification Sensor
The process begins with removing the passenger seat to access the sensor. Before you start, gather the necessary tools: a ratchet with 12mm and 14mm short sockets, red Loctite (thread locker), and a diagnostic tool capable of performing a zero-point reset and clearing fault codes. You’ll also need two replacement sensors (Nissan part number 98853-3JA0A), which are often available online at a fraction of the dealership price.
Seat Removal
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Preparation: Remove the headrest for easier maneuverability and raise the seat to its highest position. This will improve access to the sensor mounting bolts later.
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Bolt Removal: Locate and remove the four plastic covers concealing the seat mounting bolts. Use a 14mm socket to remove these bolts.
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Wiring Disconnection: Carefully tilt the seat back, avoiding damage to cables and clips. Disconnect the wiring harness connectors and release the cable clips by squeezing their ends from the back.
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Seat Removal: Gently fold and remove the seat from the vehicle.
Sensor Replacement
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Access Panel Removal: With the seat removed, locate and remove the plastic cover panel that obscures access to one of the sensor bolts. This panel is typically located on the side of the seat base (see image below).
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Bolt Removal: Loosen all sensor bolts. Use a 12mm socket for the side bolts and a 14mm socket for the center bolt. Apply caution when loosening the side bolts as the heads can easily strip. Loosening the bolts while the sensor is still in place provides better leverage. The image below highlights the bolt locations.
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Sensor Replacement: Remove the old sensors and install the new ones, applying red Loctite to the center bolt threads to secure them.
Reassembly and Reset
Reinstall the seat by reversing the removal procedure. After reconnecting the wiring harness, a zero-point reset is crucial. This procedure calibrates the new sensor. Using a compatible diagnostic tool (such as a Maxicom MK808), navigate to Control Module > Occupant Detection > Special Functions > Zero Point Reset. Finally, clear any remaining airbag fault codes. This completes the repair, effectively resolving the B00A0 Nissan error.
