B2105 — Throttle Position Input Out of Range Low #

Note: The description for DTC B2105 may differ depending on the vehicle manufacturer (OEM). Always refer to your OEM service documentation for the most accurate definition.

• B2105: Throttle Position Input Out of Range Low (Ford, Chrysler, GM)
• B2105: Accelerator Pedal Position Sensor Signal Low (Nissan)
• B2105: TP Sensor Circuit Low Input (Toyota)
• B2105: Throttle or Accelerator Sensor Out of Range Low (Mazda)

Summary of Code B2105 #

The B2105 code is triggered when the vehicle’s engine control module (ECM) or body control module (BCM) detects that the Throttle Position Sensor (TPS) or Accelerator Pedal Position (APP) sensor is reading a voltage that is below the expected range. The TPS/APP sensors communicate the position of the throttle plate or accelerator pedal to the ECM, which is critical for proper engine and transmission management. When this signal drops too low, the ECM cannot reliably interpret driver input, potentially affecting throttle control and overall drivability. The code is often accompanied by noticeable symptoms and may trigger the vehicle into a “limp” mode to protect engine and transmission components. This is a fault that should not be ignored, as it may impact both performance and safety.

Common Symptoms for Code B2105 #

A B2105 fault typically manifests through a range of drivability and warning indicators. If your vehicle is showing this code, you may notice one or more of the following symptoms:

• Check Engine Light or Service Engine Soon lamp illuminated
• Reduced engine power or limp home mode
• Unresponsive or delayed throttle response
• Engine hesitation or stumbling when accelerating
• Hard starting or stalling at idle
• Trouble shifting gears (automatic transmissions)

Probable Causes for Code B2105 #

The most common causes of a B2105 code are typically related to the throttle position sensor circuit or the accelerator pedal position sensor. Here are the most frequent sources, starting from the most likely:

1. Faulty throttle position sensor (TPS) or APP sensor
2. Damaged or corroded wiring/connectors in the TPS/APP circuit
3. Poor electrical ground for the sensor(s)
4. Sensor out of calibration or physically misaligned
5. Failed ECM/PCM/BCM (rare, but possible)

Step-by-Step Diagnosis for Code B2105 #

Diagnosing the B2105 code involves a careful inspection of the sensor, associated wiring, and related components. Here’s how a technician would typically approach this fault:

• Step 1: Use a scan tool to confirm the presence of B2105 and check for any related codes (especially P-series codes related to throttle/accelerator position).
• Step 2: Visually inspect the TPS/APP sensor and connector for corrosion, loose pins, or damage.
• Step 3: Check the wiring harness between the sensor and ECM for signs of fraying, pinching, or melting.
• Step 4: Using a multimeter, measure the reference voltage (usually 5V) and ground at the sensor connector. Confirm correct supply voltage and ground continuity.
• Step 5: With the key ON, measure the signal voltage at the sensor output. A typical TPS/APP sensor should read about 0.5V at rest and increase smoothly to about 4.5V at full throttle. A reading stuck at or near 0V indicates a problem.
• Step 6: If wiring and power are correct, replace the TPS/APP sensor and retest.
• Step 7: If the fault persists, consider a possible ECM/PCM/BCM issue and follow OEM-specific diagnostic procedures.

Possible Repairs for Code B2105 #

Correcting a B2105 code generally revolves around the throttle position or accelerator pedal position circuit. Repairs may include:

• Replacing a faulty TPS or APP sensor with a new OEM or high-quality aftermarket unit
• Repairing or replacing damaged wiring or connectors in the sensor circuit
• Cleaning corroded terminals and ensuring tight, secure connections
• Recalibrating or resetting the sensor using a scan tool or OEM procedure (if required)
• Replacing the ECM/PCM/BCM only after all other causes have been ruled out

Is It Safe to Drive with Code B2105? #

Driving with a B2105 code is generally not recommended. While the vehicle may still run, throttle response may be severely limited or unpredictable, and your car could enter “limp mode,” restricting speed and acceleration. This can create unsafe conditions, especially in traffic or when merging. Additionally, continued operation with this fault could lead to further damage or sudden stalling. It’s best to address the issue promptly before driving further.

Vehicles Most Commonly Affected by Code B2105 #

While B2105 is a generic code, it is most frequently reported in vehicles from the following OEMs:

• Ford (Focus, F-150, Escape, Fusion)
• Chrysler/Dodge/Jeep (Ram, Grand Caravan, Charger)
• General Motors (GM) (Chevrolet Silverado, Equinox, Malibu)
• Nissan (Altima, Sentra, Rogue)
• Toyota (Camry, Corolla, RAV4)
• Mazda (Mazda3, CX-5)

Common Mistakes & Best Practices for Code B2105 #

Addressing B2105 can seem straightforward, but there are pitfalls even experienced technicians can encounter. Here are some errors to avoid and best practices to follow:

• Misdiagnosing the sensor: Replacing the TPS/APP sensor without checking wiring or connector integrity first
• Ignoring related codes: Overlooking other DTCs that may point to the root cause
• Skipping voltage checks: Failing to confirm reference and signal voltages before replacing parts
• Using low-quality sensors: Aftermarket sensors with poor tolerances can cause recurring problems
• Not performing calibration: Some sensors require a reset or calibration procedure after replacement—always consult OEM specs

Quick FAQ for Code B2105 #

Here are answers to some of the most common questions about B2105:

• Q: Can a dirty throttle body cause B2105?
  A: Not typically. B2105 relates to the sensor’s electrical circuit, not mechanical throttle plate movement. However, in rare cases, severe buildup causing physical binding could trigger the code.
• Q: Will clearing the code with a scan tool fix the problem?
  A: Clearing the code will turn off the warning light temporarily, but if the underlying issue persists, the code will return as soon as the ECM detects the fault again. Always repair the root cause.