Introduction:

The B2355 diagnostic trouble code (DTC) indicates a fault within the circuit responsible for providing feedback on the position of the passenger side mirror's horizontal and vertical movement. This feedback is crucial for the vehicle's control module to accurately adjust the mirror and ensure it stops at the desired location. Understanding the potential causes, diagnostic steps, and repair procedures is essential for resolving this issue and restoring proper mirror functionality.

Comprehensive Table: B2355 DTC Details

Category Description Potential Impact
Definition Passenger Mirror Horizontal/Vertical Feedback Potentiometer Circuit Open Inability to adjust the passenger side mirror horizontally or vertically, intermittent mirror movement, mirror stopping prematurely, or complete failure of the mirror adjustment function. Compromised driver visibility and safety.
Possible Causes Open circuit in the wiring to the potentiometer, faulty potentiometer, damaged connector, corroded terminals, faulty mirror control switch, faulty body control module (BCM), broken or damaged mirror motor assembly, wiring harness damage due to physical impact or rodent activity. Incorrect mirror positioning, difficulty adjusting the mirror to the desired position, safety concerns due to impaired visibility, potential for accidents if the mirror cannot be adjusted properly.
Symptoms Passenger side mirror does not move horizontally or vertically, intermittent mirror movement, mirror moves in only one direction, mirror moves erratically, mirror control switch unresponsive, DTC B2355 is stored in the vehicle's computer.
Diagnostic Steps Visual inspection of wiring and connectors, multimeter testing of circuit continuity and voltage, scan tool data analysis, potentiometer resistance check, mirror motor test, BCM diagnostic testing.
Common Repair Solutions Repairing or replacing damaged wiring, replacing the passenger side mirror assembly, replacing the mirror control switch, replacing the body control module (BCM), cleaning corroded terminals, securing loose connections.
Related DTCs B2350-B2359 (other mirror related codes), U codes (communication errors related to the BCM or other modules), B codes (body control module related codes).
Components Involved Passenger side mirror assembly, mirror motor, potentiometer, wiring harness, connectors, mirror control switch, body control module (BCM).
Technical Details (Potentiometer) Typically a 3-wire potentiometer providing variable resistance based on mirror position. Resistance values should change smoothly as the mirror is adjusted. Open circuit will result in very high or infinite resistance readings. Reference voltage (typically 5V) is supplied by the BCM. Signal wire returns voltage proportional to mirror position back to the BCM. Ground wire provides a stable ground connection.
Voltage Readings (Expected) Reference Voltage: Approximately 5V. Signal Voltage: Varies between 0V and 5V depending on mirror position. Ground: 0V. These readings are crucial for diagnosing wiring issues and potentiometer functionality.
Resistance Readings (Expected) Potentiometer resistance should change smoothly and proportionally as the mirror is adjusted. Specific resistance range varies depending on the vehicle make and model. A break in the circuit will result in a very high or infinite resistance reading.

Detailed Explanations:

Definition: Passenger Mirror Horizontal/Vertical Feedback Potentiometer Circuit Open

This DTC signifies that the vehicle's computer (typically the Body Control Module - BCM) has detected an open circuit in the feedback loop associated with the potentiometer that monitors the position of the passenger side mirror during horizontal and/or vertical adjustments. An "open circuit" means that the electrical circuit is broken, preventing the flow of electricity. This prevents the BCM from knowing the exact position of the mirror.

Possible Causes: Open Circuit in the Wiring to the Potentiometer

The wiring harness connecting the potentiometer to the BCM is susceptible to damage. This can occur due to physical stress, chafing against sharp edges, rodent activity, or exposure to harsh environmental conditions. A break in any of the wires (reference voltage, signal, or ground) will create an open circuit and trigger the B2355 code.

Possible Causes: Faulty Potentiometer

The potentiometer itself can fail. Internal wear and tear, corrosion, or physical damage can cause the potentiometer to develop an open circuit internally. This prevents the potentiometer from accurately sending feedback signals to the BCM.

Possible Causes: Damaged Connector

The connectors that attach the wiring harness to the mirror assembly and the BCM are critical points of potential failure. Damaged or broken connector housings can expose the terminals to corrosion and moisture, leading to an open circuit.

Possible Causes: Corroded Terminals

Corrosion on the electrical terminals within the connectors or on the potentiometer itself can create a high-resistance connection or an open circuit. This is especially common in areas with high humidity or exposure to road salt.

Possible Causes: Faulty Mirror Control Switch

While less common, a faulty mirror control switch can contribute to the problem. If the switch is not properly sending the adjustment signals, it can indirectly affect the feedback circuit and trigger the code.

Possible Causes: Faulty Body Control Module (BCM)

The BCM is the computer that interprets the potentiometer's feedback signal. A faulty BCM might misinterpret or fail to receive the signal, incorrectly diagnosing an open circuit. This is typically a last resort diagnosis after all other possibilities have been ruled out.

Possible Causes: Broken or Damaged Mirror Motor Assembly

While the DTC specifically points to the potentiometer circuit, a severely damaged mirror motor assembly could indirectly impact the feedback circuit. If the motor is completely seized, it could prevent the potentiometer from functioning correctly.

Possible Causes: Wiring Harness Damage Due to Physical Impact or Rodent Activity

Accidents or collisions can directly damage the wiring harness. Rodents are also known to chew on wiring, creating open circuits. Inspect the wiring harness thoroughly for any signs of physical damage.

Symptoms: Passenger Side Mirror Does Not Move Horizontally or Vertically

This is the most obvious symptom. If the mirror doesn't respond at all to the adjustment controls, it strongly suggests a problem with the motor, wiring, or potentiometer circuit.

Symptoms: Intermittent Mirror Movement

The mirror might move erratically or only function intermittently. This can indicate a loose connection or a partial break in the wiring, causing the circuit to open and close sporadically.

Symptoms: Mirror Moves in Only One Direction

If the mirror only moves horizontally or vertically, but not both, it suggests a problem specific to one of the feedback circuits within the potentiometer.

Symptoms: Mirror Moves Erratically

The mirror might move in unexpected directions or stop prematurely. This is often caused by a faulty potentiometer sending incorrect position data to the BCM.

Symptoms: Mirror Control Switch Unresponsive

The mirror control switch might appear to be completely dead, with no response from the mirror when the switch is activated.

Symptoms: DTC B2355 is Stored in the Vehicle's Computer

This is the definitive sign that the vehicle's computer has detected a problem with the passenger side mirror's feedback circuit. The DTC can be read using a scan tool.

Diagnostic Steps: Visual Inspection of Wiring and Connectors

Begin by visually inspecting the wiring harness and connectors associated with the passenger side mirror. Look for any signs of damage, such as frayed wires, broken connectors, corrosion, or rodent damage.

Diagnostic Steps: Multimeter Testing of Circuit Continuity and Voltage

Use a multimeter to test the continuity of the wiring between the potentiometer and the BCM. Also, check for proper voltage at the potentiometer connector. Verify that the reference voltage (typically 5V) is present and that the ground connection is solid.

Diagnostic Steps: Scan Tool Data Analysis

Connect a scan tool to the vehicle's diagnostic port and retrieve any stored DTCs. Observe live data related to the mirror position sensor to see if the signal is erratic or missing.

Diagnostic Steps: Potentiometer Resistance Check

Use a multimeter to measure the resistance across the potentiometer terminals. As the mirror is manually adjusted, the resistance should change smoothly and proportionally. An open circuit will result in a very high or infinite resistance reading.

Diagnostic Steps: Mirror Motor Test

Directly apply voltage to the mirror motor to verify that it functions correctly. If the motor doesn't respond, it may be faulty and need replacement.

Diagnostic Steps: BCM Diagnostic Testing

If all other components appear to be functioning correctly, the BCM may be the source of the problem. Consult a qualified technician for BCM diagnostic testing and potential reprogramming.

Common Repair Solutions: Repairing or Replacing Damaged Wiring

If damaged wiring is found, repair it by splicing in new sections of wire and using heat-shrink tubing to protect the connections. In severe cases, the entire wiring harness may need to be replaced.

Common Repair Solutions: Replacing the Passenger Side Mirror Assembly

If the potentiometer is integrated into the mirror assembly and cannot be replaced separately, the entire mirror assembly may need to be replaced.

Common Repair Solutions: Replacing the Mirror Control Switch

If the mirror control switch is faulty, replace it with a new one.

Common Repair Solutions: Replacing the Body Control Module (BCM)

If the BCM is determined to be the cause of the problem, it will need to be replaced and reprogrammed by a qualified technician.

Common Repair Solutions: Cleaning Corroded Terminals

Clean corroded terminals with a wire brush and electrical contact cleaner. Apply dielectric grease to the terminals to prevent future corrosion.

Common Repair Solutions: Securing Loose Connections

Ensure that all electrical connectors are properly seated and secured. Use zip ties or electrical tape to prevent them from coming loose.

Related DTCs: B2350-B2359 (other mirror related codes), U codes (communication errors related to the BCM or other modules), B codes (body control module related codes)

These codes can provide additional clues about the root cause of the problem. For example, a U code might indicate a communication issue between the BCM and another module.

Components Involved: Passenger side mirror assembly, mirror motor, potentiometer, wiring harness, connectors, mirror control switch, body control module (BCM)

Understanding the location and function of each of these components is crucial for effective troubleshooting.

Technical Details (Potentiometer)

The potentiometer is a variable resistor that provides feedback to the BCM about the mirror's position. It typically has three wires: a reference voltage (usually 5V), a ground, and a signal wire. As the mirror moves, the resistance of the potentiometer changes, which alters the voltage on the signal wire. The BCM interprets this voltage change to determine the mirror's position.

Voltage Readings (Expected)

  • Reference Voltage: Approximately 5V
  • Signal Voltage: Varies between 0V and 5V depending on mirror position
  • Ground: 0V

Resistance Readings (Expected)

Potentiometer resistance should change smoothly and proportionally as the mirror is adjusted. Specific resistance range varies depending on the vehicle make and model.

Frequently Asked Questions:

  • What does the B2355 code mean? It indicates an open circuit in the feedback loop for the passenger side mirror's horizontal/vertical adjustment.

  • Can I fix this myself? With proper tools and knowledge of electrical systems, you may be able to diagnose and repair simple wiring issues. However, more complex repairs may require a qualified technician.

  • How much does it cost to fix? The cost varies depending on the cause of the problem. Replacing a wiring harness or the entire mirror assembly will be more expensive than repairing a loose connection.

  • Is it safe to drive with this code? While the mirror may not adjust properly, it's generally safe to drive as long as you can still maintain adequate visibility. However, it's recommended to address the issue as soon as possible.

  • What tools do I need to diagnose this problem? A multimeter, scan tool, wiring diagrams, and basic hand tools are essential for diagnosing this issue.

Conclusion:

The B2355 DTC signifies a problem with the passenger side mirror's feedback circuit. Thorough diagnosis and repair are essential to restore proper mirror functionality and ensure driver safety. Start with visual inspection and basic electrical testing, and consult a qualified technician if needed.