B0121 - Right Front Seat Belt Buckle Switch Malfunction

Repair Importance Level: 3/3
Repair Difficulty Level: 3/3  What does this mean?

B0121 Possible Causes

  • Faulty Right Front Seat Belt Buckle Switch
  • Right Front Seat Belt Buckle Switch harness is open or shorted
  • Right Front Seat Belt Buckle Switch circuit poor electrical connection
  • Faulty Air Bag Control Module

First diagnose B0121 code

    Check the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded terminals.

Cost of diagnosing the B0121 code

    Labor: 1.0

    The cost of diagnosing the B0121 code is 1.0 hour of labor. The auto repair labor rates vary widely across the country, and even within the same city. Most auto repairs shops charge between $75 and $150 per hour.

B0121 Possible Symptoms

  • Air Bag Warning Light ON

B0121 Meaning

The right front seat belt buckle switch circuit consists of the air bag center sensor and right front seat belt buckle assembly. The Air Bag Control Module monitors the Right Front Seat Belt Buckle Switch. The Air Bag Control Module sets the OBDII code when the Right Front Seat Belt Buckle Switch is not to factory specifications.
OBDII Code B0121 - Right Front Seat Belt Buckle Switch Malfunction - Engine-Codes.com

B0121 More Information

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B0121 Information for specific makes

  • B0121 LEXUS Right Front Seat Belt Buckle Switch Malfunction
  • B0121 SCION Right Front Seat Belt Buckle Switch Malfunction
  • B0121 TOYOTA Right Front Seat Belt Buckle Switch Malfunction

Precautions for SRS “AIR BAG” and “SEAT BELT PRE-TENSIONER” Service

  • Never probe the electrical connectors on air bag, side air curtain modules or seat belts.
  • Never disassemble or tamper with safety belt buckle/retractor pretensioners, adaptive load limiting retractors, safety belt inflators, or probe the electrical connectors.
  • Do not use electrical test equipment to check SRS circuits unless instructed to in this Service Manual.
  • Before servicing the SRS, turn ignition switch OFF, disconnect both battery cables and wait at least 3 minutes. For approximately 3 minutes after the cables are removed, it is still possible for the air bag and seat belt pre-tensioner to deploy. Therefore, do not work on any SRS connectors or wires until at least 3 minutes have passed.
Failure to follow this instruction may result in the accidental deployment of these modules, which increases the risk of serious personal injury or death.

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