B2106 code definition

The B2106 trouble code notes an error with the throttle position input range.

What the B2106 code means

The B2106 code is a standard OBD-II trouble code for the four-wheel drive (4WD) system, that detects a range issue with the throttle position input. Vehicles utilize throttle pedal position sensors, which relay the pedal position information to the powertrain control module (PCM), which calculates the proper fuel strategy based on this info. For cars that have a 4WD system, the PCM sends this information to the 4WD control module, which relies on this data to control the use of the 4WD clutch. Any time that the 4WD control module is not receiving this information from the PCM, then it is likely that the P2106 trouble code will be detected.

What causes the B2106 code?

The B2106 trouble code is usually caused by a damaged circuit in the 4WD system, which can be the result of a shorted wires, loose harnesses, disconnected grounds, or blown fuses. The code is also commonly caused by loose connectors in the 4WD control module. While very rare, it is possible for the code to be triggered due to a 4WD control module or PCM failure.

While those are the causes commonly associated with this code, the B2106 code may also be stored due to a throttle pedal position sensor failure. Throttle position sensor failure is usually caused by a damaged sensor, a misadjusted sensor, a malfunctioning throttle body, or damaged electrical components in the throttle position sensor system. However, if any of these issues are the cause of the B2106 trouble code, then there will also be a throttle position sensor powertrain trouble code, which should be diagnosed before the B2106 code.

What are the symptoms of the B2106 code?

If the B2106 trouble code is present, then it is likely that the 4WD system will have some issues, because the 4WD clutch will not have the throttle position input data that it requires to function properly. As a result, the vehicle will likely experience more slippage than it normally would, and it is possible that the car will be incapable of shifting into or out of 4WD. It is also likely that the 4WD Warning Light and check engine soon Warning Lights will illuminate on the instrument panel.

In addition to these symptoms, if the vehicle has throttle pedal position powertrain trouble codes that have been detected, then there will probably be drivability symptoms such as poor acceleration, frequent stalling, black smoke upon startup, or an inability to turn on.

How does a mechanic diagnose the B2106 code?

The B2106 code will be diagnosed with the help of a basic OBD-II trouble code scanner. A trained technician will view the freeze frame data on the scanner to gather information about the B2106 code. Additional trouble codes will also be checked for, and, if present, will need to be diagnosed in the order that they appear in. The trouble codes will then be reset, the vehicle restarted, and the B2106 code searched for again. If the code is no longer present, then an intermittent error or an inaccurate detection are likely to blame.

If the B2106 code is still present after the reset, and throttle pedal position sensor powertrain trouble codes are listed above it, then it is probable that the B2106 code will be resolved when the powertrain codes are diagnosed. If there are no powertrain codes present, then the technician will begin by inspecting and testing the circuits in the 4WD system, and replacing any parts that are damaged or otherwise compromised. Next, the 4WD control module will need to be disconnected, and the mechanic will check the controller connectors.

When any parts are repaired or replaced, the diagnosis should be paused while the codes are reset, the vehicle restarted, and the B2106 code searched for again. This will alert the mechanic as soon as the problem is solved.

Common mistakes when diagnosing the B2106 code

The most frequently made mistake when diagnosing the B2106 code comes from not following the OBD-II trouble code diagnosis protocol. The diagnosis protocol should be observed at all times, because it increases the chances of a thorough diagnosis, and an efficient and accurate repair.

It’s fairly common for fully functional 4WD control modules to be inaccurately condemned because the circuits and electrical components were overlooked.

How serious is the B2106 code?

If the B2106 trouble code is detected, then the vehicle will likely struggle with the 4WD system. The vehicle may not be able to access 4WD, or shift out of 4WD, and more importantly, there will likely be excess slippage because of the inoperable 4WD clutch. If any throttle position sensor powertrain trouble codes are also present, the vehicle may have severe drivability concerns, and may not even be able to start. As soon as the B2106 code is detected, an inspection should be scheduled.

What repairs can fix the B2106 code?

Some repairs for the B2106 trouble code are:

  • Replacement of 4WD system circuits
  • Repair of the 4WD control module connectors
  • Replacement of wires, fuses, and connectors in the throttle position sensor
  • Replacement of the throttle position sensor
  • Replacement of the throttle body
  • In very rare cases, replacement of the PCM or 4WD control module

Additional comments for consideration regarding the B2106 code?

The B2106 code is a manufacturer specific trouble code. Manufacturer specific codes have varying definitions from manufacturer to manufacturer. While this code detects a throttle position input range problem in some cars, it can suggest an entirely different problem with other automakers. As is always the case, the mechanic should be aware of what vehicle is being worked on when diagnosing this code.

The B2106 code only applies to vehicles that have 4WD or all-wheel drive systems.

Need help with a B2106 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.

This article originally appeared on YourMechanic.com as B2106 OBD-II Trouble Code: Throttle Position Input Out of Range High and was authored by Brady Klopfer.


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