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B1986 OBD-II Trouble Code: Driver's Seat Seatback Autoglide Rearward Switch Circuit Failure

diagnostic check engine light

B1986 code definition

A B1986 trouble code indicates that the Engine Control Unit (ECU) has detected an unspecified circuit failure in the driver seat's autoglide rearward switch circuit.

What the B1986 code means

The autoglide feature helps enable easier access to the driver's seat. When the engine's ignition is triggered, the seat will glide closer to the steering wheel. Conversely, when the engine is turned off, the seat will automatically pull out slightly, offering more room to move out. With a B1986 circuit failure, the autoglide won't shift back on its own when the engine is turned off.

What causes the B1986 code?

If the ECU has reported a failure in the autoglide rearward switch circuit, there is very likely to be a faulty or failed segment at some point of the circuit. Issues in the wiring related to the switch circuit may be to blame for the B1986 code. Disconnected, damaged, faulty and improperly installed wiring can account for the issue. In some, rarer cases, the ECU itself may be reporting the switch circuit's failure falsely, and may be faulty itself. Although this possibility should only be considered once all other explanations have been exhausted, false trouble codes have been reported as a result of malfunctioning ECUs.

What are the symptoms of the B1986 code?

If a B1986 has occurred, the autoglide feature will not work when the engine is shut off. Considering the close relation between the two, it is likely the autoglide won't work moving forward either. Moreover, the B1986 will come along with a stored trouble code and illuminated check engine lamp. These are present for a purely diagnostic purpose, and may be disregarded if you have already identified the issue at hand.

How does a mechanic diagnose the B1986 code?

A mechanic may first diagnose the B1986 trouble code by scanning the code on the ECU with an OBD-II code scanner. From there, the circuit should be accessed and examined thoroughly for signs of disconnection, damage, faultiness and/or corrosion. The seat sensor should be examined as well for signs of fault. It may be found directly underneath the driver's seat.

Common mistakes when diagnosing the B1986 code

The B1986 is a body-related (or "B" class) trouble code. Body codes may stand for different issues depending on the type of vehicle and its manufacturer. Although your OBD-II code scanner may specify the code description for you, make sure that you don't confuse one code description for another. This can result in needless repairs for functional components, and will leave the actual problem unresolved. Refer to your vehicle manual if you're unsure.

How serious is the B1986 code?

The B1986 trouble code doesn't affect a vehicle's drivability, nor does it make access to the driver's seat significantly more difficult. The autoglide feature is a subtle luxury, and unless the B1986 code has come alongside other, more pressing issue, you shouldn't need to worry about it. Address the code at your own discretion.

What repairs can fix the B1986 code?

The autoglide sensor should be repaired or replaced if it's been found out as faulty. Any concerns with electrical wiring should be addressed, either with regards to replacing, repairing or simply rewiring the segments at fault. If the ECU has mistakenly reported the issue and is faulty, it will need to be repaired and reprogrammed, or replaced outright. Following any repairs made to address the B1986 trouble code, the vehicle should be quickly retested. Starting up the car and testing the seat will quickly allow you to know whether or not the issue has actually be resolved. If it hasn't, return to the diagnostic stage and see if you missed out on anything.

Additional comments for consideration regarding the B1986 code

Issues relating to the diver's seat should be taken more seriously than other eats, given the fact they may affect (and most often hinder) driving performance.

Need help with a B1986 code?

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The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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