B2101 OBD-II Trouble Code: Head Rest Switch Circuit Failure

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Cost of diagnosing the B2101 code

B2101 is a diagnostic trouble code (DTC) for "Head Rest Switch 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 diagnostic. 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.

Cars Estimate Credit towards follow-up repair Earliest Availability
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Toyota$20.00
BMW$20.00
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B2101 code definition

The B2101 trouble code notes a circuit failure from the power headrest switch.

What the B2101 code means

The B2101 code is a standard OBD-II body trouble code that detects a power headrest switch circuit malfunction. Power headrests are a relatively rare interior feature that allow the driver and front passenger to adjust their seat headrests using a switch, rather than manually. If the body control module or powertrain control module (PCM) detect a circuit failure from the power headrest switch, then the B212 trouble code could be triggered.

What causes the B2101 code?

The most common cause of the B2101 trouble code is damaged electrical components, either in the power headrest switch, or in the power headrest itself. This usually takes the form of shorted wires, but can also be loose or corroded connectors, or blown fuses. Other common causes are a defective power headrest motor, a malfunctioning power headrest switch, and a stuck or damaged adjustment rail. While rare, the code can also be the result of a faulty body control module.

What are the symptoms of the B2101 code?

A vehicle with a detected B2101 code will likely have inoperable power headrests, which means that the headrests cannot be adjusted (in some cars they can still be adjusted manually). It is also possible that the check engine soon Warning Light will illuminate.

How does a mechanic diagnose the B2101 code?

The B2101 code will be diagnosed using a standard OBD-II trouble code scanner. A certified mechanic will use the scanner to view the freeze frame data and assess the B2101 code. The scanner will also be used to check for the presence of any other trouble codes that have been detected. If there are numerous codes present, then they will need to be inspected in the order that they appear in. The codes will then be reset, and the vehicle restarted, so the technician can see if the B2101 code remains present. If it does not, then it was most likely inaccurately detected, or is the result of an intermittent problem.

If the B2101 code is still detected, then the mechanic should thoroughly inspect all of the electrical components in the power headrest system, and replace any wires, connectors, or fuses that are damaged in any way. Next, the technician will inspect the power headrest system, to see if the headrest motor and adjustment rail are operating properly. Finally, the power headrest switch itself should be inspected.

After any components are repaired or replaced, the technician will reset the trouble codes, restart the vehicle, and again check for the presence of the B2101 code. By doing this, the mechanic will be alerted as soon as the issue is fully resolved.

Common mistakes when diagnosing the B2101 code

The most commonly made mistake when diagnosing the B2101 code comes from a failure to properly adhere to the OBD-II diagnosis protocol. The diagnosis protocol should be observed by mechanics at all times, to help avoid unnecessary replacements.

Power headrest switches and motors are often erroneously replaced because the electrical system was not first inspected.

How serious is the B2101 code?

A vehicle with the B2101 trouble code will have no drivability concerns. However, the power headrest system will likely be inoperable, which means that you may not be able to adjust the headrests. This can cause comfort or practicality concerns, especially if the headrest is stuck in an awkward position. When this code is detected, an inspection should be scheduled.

What repairs can fix the B2101 code?

Repairs for the B2101 trouble code include:

Additional comments for consideration regarding the B2101 code

The B2101 trouble code is a manufacturer specific code, which means that the definition varies from manufacturer to manufacturer. Since power headrests aren’t found in most vehicles, the B2101 code usually detects a different body failure. As always, the mechanic should note the vehicle that is being worked on when diagnosing this code.

Need help with a B2101 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

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