Introduction:
The B2155 diagnostic trouble code (DTC) indicates an issue with the horizontal seat motor position sensor in a vehicle's power seat system. This code signals that the seat control module (SCM) has detected that the signal from the horizontal seat motor position sensor is outside of its expected or calibrated range. Addressing this code promptly is crucial for restoring proper seat functionality and ensuring driver comfort and safety.
Table: B2155 Seat Horizontal Motor Position Out of Range - Comprehensive Information
| Category | Information | Possible Causes |
|---|---|---|
| Definition | B2155 - Seat Horizontal Motor Position Out of Range | Faulty horizontal seat motor position sensor; Wiring harness issues (open circuit, short circuit, high resistance); Corroded connectors; Faulty seat control module (SCM); Mechanical binding or obstruction in the seat track; Incorrect seat calibration; Low battery voltage; Loose ground connection; Internal motor failure; Software glitch in SCM. |
| Symptoms | Malfunctioning power seat (horizontal movement); Seat not moving at all horizontally; Intermittent seat movement; "Check Engine" light or other warning lights illuminated; Diagnostic trouble code B2155 stored in the vehicle's computer; Unusual noises during seat adjustment; Seat position memory not functioning correctly; Seat moving too far forward or backward. | |
| Troubleshooting Steps | Visual inspection of wiring and connectors; Scan for other DTCs; Check power and ground to the seat motor; Test the horizontal seat motor position sensor with a multimeter; Perform a seat calibration procedure; Check for mechanical binding in the seat track; Inspect the seat motor itself; Test the seat control module (SCM); Check battery voltage and charging system; Consult vehicle-specific repair information. |
Detailed Explanations
Definition: B2155 - Seat Horizontal Motor Position Out of Range
The B2155 code signifies that the vehicle's computer, specifically the Seat Control Module (SCM), has detected that the signal coming from the horizontal seat motor position sensor is not within the acceptable parameters. This sensor provides feedback to the SCM about the seat's current horizontal position, allowing the module to control the seat motor and maintain the desired position. When the signal falls outside the expected range, the B2155 code is triggered. This can occur if the signal is too high, too low, erratic, or completely absent.
Symptoms: Malfunctioning Power Seat (horizontal movement)
The most obvious symptom of a B2155 code is a problem with the horizontal adjustment of the power seat. This can manifest in several ways: the seat may not move at all horizontally, it may move intermittently, it may move erratically, or it may move too far in one direction. Other symptoms may include the "Check Engine" light illuminating, unusual noises during seat adjustment, seat position memory malfunctioning, or the seat moving too far forward or backward. The presence of other DTCs related to the seat system or the vehicle's overall electrical system can also provide clues.
Possible Causes: Faulty horizontal seat motor position sensor
The horizontal seat motor position sensor itself is a common culprit. These sensors can fail due to wear and tear, exposure to moisture, or electrical damage. A faulty sensor may provide an inaccurate or absent signal to the SCM, triggering the B2155 code.
Possible Causes: Wiring harness issues (open circuit, short circuit, high resistance)
The wiring harness connecting the sensor to the SCM is another potential source of problems. An open circuit (broken wire), a short circuit (wire grounding out), or high resistance (corroded or damaged wire) can disrupt the signal and cause the B2155 code. Inspect the wiring for any signs of damage, such as frayed insulation, broken wires, or corrosion.
Possible Causes: Corroded connectors
Corroded connectors can also impede the signal transmission between the sensor and the SCM. Corrosion can build up over time due to exposure to moisture and contaminants. Inspect the connectors for any signs of corrosion and clean them thoroughly with an appropriate electrical contact cleaner.
Possible Causes: Faulty seat control module (SCM)
Although less common, a faulty SCM can also be the cause of the B2155 code. The SCM is responsible for processing the signal from the sensor and controlling the seat motor. If the SCM is malfunctioning, it may misinterpret the signal or fail to control the motor properly.
Possible Causes: Mechanical binding or obstruction in the seat track
Mechanical binding or an obstruction in the seat track can prevent the seat from moving freely. This can put undue stress on the motor and sensor, leading to inaccurate readings and the B2155 code. Inspect the seat track for any obstructions, such as debris or foreign objects, and ensure that the seat moves smoothly.
Possible Causes: Incorrect seat calibration
Some vehicles require a seat calibration procedure after certain repairs or replacements. If the seat is not properly calibrated, the SCM may not be able to accurately determine the seat's position, leading to the B2155 code. Refer to the vehicle's service manual for the correct calibration procedure.
Possible Causes: Low battery voltage
Low battery voltage can sometimes cause electrical systems to malfunction, including the power seat system. Ensure that the battery is properly charged and in good condition.
Possible Causes: Loose ground connection
A loose ground connection can disrupt the flow of electricity and cause various electrical problems, including the B2155 code. Check the ground connections for the seat system and ensure that they are clean and tight.
Possible Causes: Internal motor failure
Although less common, internal failure of the seat motor can cause the position sensor to report inaccurate readings. The motor might be drawing too much current or not providing the correct feedback.
Possible Causes: Software glitch in SCM
In rare cases, a software glitch in the seat control module (SCM) can cause the B2155 code. This is usually resolved by reprogramming or updating the SCM software.
Troubleshooting Steps: Visual inspection of wiring and connectors
Begin by visually inspecting the wiring and connectors associated with the horizontal seat motor and position sensor. Look for any signs of damage, such as frayed wires, broken connectors, or corrosion.
Troubleshooting Steps: Scan for other DTCs
Use a scan tool to check for any other diagnostic trouble codes (DTCs) related to the seat system or the vehicle's overall electrical system. Other codes may provide clues about the underlying cause of the B2155 code.
Troubleshooting Steps: Check power and ground to the seat motor
Use a multimeter to check that the seat motor is receiving the correct power and ground signals. A lack of power or a poor ground connection can prevent the motor from functioning properly.
Troubleshooting Steps: Test the horizontal seat motor position sensor with a multimeter
Use a multimeter to test the horizontal seat motor position sensor according to the manufacturer's specifications. This will help determine if the sensor is functioning properly and providing an accurate signal.
Troubleshooting Steps: Perform a seat calibration procedure
If the vehicle requires a seat calibration procedure, perform it according to the manufacturer's instructions. This may resolve the B2155 code if the seat is not properly calibrated.
Troubleshooting Steps: Check for mechanical binding in the seat track
Inspect the seat track for any mechanical binding or obstructions that may be preventing the seat from moving freely.
Troubleshooting Steps: Inspect the seat motor itself
Visually inspect the seat motor for any signs of damage, such as cracks or leaks.
Troubleshooting Steps: Test the seat control module (SCM)
Testing the SCM typically requires specialized equipment and knowledge. It is often best to consult a qualified technician for this step.
Troubleshooting Steps: Check battery voltage and charging system
Ensure the battery voltage is within the specified range and that the charging system is functioning correctly. A weak battery can cause various electrical issues.
Troubleshooting Steps: Consult vehicle-specific repair information
Always consult the vehicle's service manual or other repair information for specific troubleshooting procedures and diagnostic tips.
Frequently Asked Questions
What does the B2155 code mean?
The B2155 code means the seat control module has detected that the horizontal seat motor position sensor signal is out of range. This indicates a problem with the sensor, wiring, or the module itself.
Can I fix the B2155 code myself?
Depending on your mechanical skills, you might be able to diagnose and fix the problem. Start with a visual inspection and basic tests, but more complex repairs may require a professional.
How much does it cost to fix the B2155 code?
The cost varies depending on the cause. A simple wiring repair might be inexpensive, while replacing the sensor or SCM can be more costly. Expect to pay for parts and labor if you take it to a mechanic.
What are the common causes of the B2155 code?
Common causes include a faulty horizontal seat motor position sensor, wiring problems, corroded connectors, or a faulty seat control module. Mechanical binding can also contribute.
Is it safe to drive with the B2155 code?
While the code itself doesn't pose an immediate safety risk, a malfunctioning seat can be uncomfortable and potentially distracting while driving. It's best to address the issue promptly.
How do I clear the B2155 code?
You can clear the code using an OBD-II scanner. However, the code will likely return if the underlying problem is not fixed.
Will a dead battery cause a B2155 code?
Yes, a low or dead battery can sometimes trigger a B2155 code due to voltage fluctuations affecting the sensor readings.
Can I use a generic OBD2 scanner to read B2155?
Yes, a generic OBD2 scanner should be able to read the B2155 code, but a more advanced scanner might provide more specific information about the fault.
Does the B2155 code affect other systems in the car?
Generally, the B2155 code primarily affects the power seat functionality. However, electrical issues can sometimes have cascading effects, so it's important to address the problem properly.
How often does the seat motor position sensor fail?
Seat motor position sensor failure is relatively common, especially in older vehicles or those exposed to moisture or harsh conditions.
Conclusion:
The B2155 code indicates a problem with the horizontal seat motor position sensor circuit, leading to issues with the power seat. Thorough diagnosis and repair are essential to restore proper seat function and driver comfort.