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B1984 is a diagnostic trouble code (DTC) for "Seat Switch Lumbar Inflate Circuit Failure". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light is on diagnostic inspection. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.
A B1984 trouble code indicates that the vehicle's Engine Control Unit (ECU) has detected an unspecified failure regarding the seat switch's lumbar inflate circuit.
The lumbar circuits are so-named for relating to the lower region of the back. Certain luxury models of car will come equipped with these adjustable cushions which, when controlled, can help you sculpt the seat to suit your back. If a B1984 trouble code has been reported, the lumbar inflate circuit has suffered an unspecified failure. This will likely restrict the ability to inflate the cushion.
Faulty components and electrical circuitry are most often to blame for an unspecified circuit failure. Some cases of the B1984 trouble code may be reported falsely by a malfunctioning ECU. Although this is a much rarer scenario than a failed circuit, it may be considered if all other plausible explanations have been exhausted.
A B1984 will restrict the lumbar control's ability to inflate (or harden) the lumbar cushion. In addition, the B1984 trouble code will come along with a stored trouble code and illuminated check engine lamp on the dashboard. These symptoms are diagnostic in nature, and are used to identify the issue in the first place.
A mechanic may first diagnose the B1984 trouble code by reading the ECU with an OBD-II code scanner. The lumbar circuit may be found underneath the seat in question. From there, the lumbar circuit should be thoroughly inspected, checking for any apparent stops or damages relating to the electrical wiring or connectors. If all of the lumbar circuitry checks out, inspect the ECU for potential signs of malfunction.
A B1984 is a body-related trouble codes. B-class codes can pose a risk of misinterpretation for home repairs, as one code can stand for different issues depending on the make and model of vehicle. Your OBD-II code reader may specify the issue for you. If you're not sure of the description, refer to the user manual or contact the manufacturer. Going through with repairs to an unrelated problem can be a major nuisance and risk wasted investment. All the while, the real problem will remain unaddressed.
Because of the pure luxury factor of a lumbar cushion, a B1984 trouble code shouldn't be seen as a serious problem, and can be repaired purely at the owner's discretion. Although no lumbar-related codes should be seen as serious concerns, the B1984 is slightly less serious than its B1985 ("cannot deflate lumbar") counterpart. This is because a highly inflated lumbar may prove more uncomfortable to a driver than a deflated cushion.
If you have noted any wiring as being faulty, damaged, disconnected or otherwise problematic, it should be replaced, repaired, or rewired accordingly. In the event ECU has been proven faulty, it will need to be reprogrammed or replaced. Upon completing your repairs for the B1984 code, restart the vehicle to see if the code recurs. If the code returns upon restarting, you should return to the diagnostic phase of repair and see if you missed anything the first time around.
You can purchase an independent lumbar cushion if you'd like to retain the lumbar support without making the repairs.
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