Introduction
The B2346 diagnostic trouble code (DTC) indicates a fault within the power mirror system of a vehicle. Specifically, it signals an open circuit on the reference voltage line that supplies power to the mirror switch. This open circuit prevents the switch from functioning correctly, leading to a loss of control over the power mirrors. Diagnosing and resolving this issue requires understanding the mirror system's electrical architecture and employing proper troubleshooting techniques.
Comprehensive Table
| Category | Description | Potential Causes |
|---|---|---|
| DTC Definition | B2346 - Mirror Switch Reference Voltage Positive Common Open Circuit | Open circuit in the 5V reference wire, faulty mirror switch, wiring harness damage, loose connections, corroded terminals, ECM/BCM malfunction (rare). |
| Affected System | Power Mirror System | Driver and/or passenger side power mirrors. |
| Symptoms | Power mirrors inoperative, no mirror adjustment possible, other electrical issues potentially if the reference voltage is shared. | Mirrors do not respond to switch inputs, potential for other modules relying on the same reference voltage to also malfunction. |
| Voltage Reference | Typically 5V, supplied by the Engine Control Module (ECM) or Body Control Module (BCM). | Used by the mirror switch as a baseline for interpreting input signals. Absence of voltage disrupts switch operation. |
| Wiring Diagram Location | Vehicle-specific repair manual, online repair databases (e.g., Alldata, Mitchell OnDemand). | Essential for tracing the circuit and identifying potential break points. |
| Connector Pinouts | Vehicle-specific repair manual, online repair databases. | Crucial for testing voltage at specific points in the circuit. |
| Tools Required | Multimeter, wiring diagram, terminal test kit, wire strippers, crimpers, electrical contact cleaner, diagnostic scan tool (optional). | Multimeter for voltage and continuity testing. Terminal test kit for accessing small connectors. Wire strippers and crimpers for wiring repairs. Contact cleaner to eliminate corrosion. |
| Diagnostic Procedure Steps | Visual inspection, voltage testing at the mirror switch connector, continuity testing of the wiring harness, component replacement (if necessary). | Thorough inspection is key to identifying the root cause. Logical testing isolates the fault. |
| Common Failure Points | Mirror switch connector, wiring harness near the door hinge, ECM/BCM connector. | These locations are susceptible to wear and tear, corrosion, and physical damage. |
| Potential Related DTCs | Other DTCs related to the power mirror system, ECM/BCM, or reference voltage circuits. | Presence of other DTCs can provide additional clues about the root cause of the B2346 code. |
| Impact on Vehicle Operation | Inconvenience due to inability to adjust mirrors, potential safety hazard (limited visibility). | While not directly impacting engine performance, the inability to adjust mirrors can compromise safety. |
| Repair Verification | Verify mirror operation, clear DTC, perform a test drive to confirm the issue is resolved. | Ensuring the repair is effective and the code does not return. |
| Reference Voltage Function | Provides a stable voltage source for the switch to use as a reference. | This allows the switch to accurately signal the control module based on the user's input. |
| Open Circuit Location | Anywhere along the 5V reference wire between the ECM/BCM and the mirror switch. | Could be a broken wire, corroded connector, or a faulty component in the circuit. |
| Potential for Intermittency | Yes, especially if caused by loose connections or vibration. | The problem might come and go depending on vehicle movement and environmental conditions. |
| Component Resistance Values | Varies depending on the vehicle and mirror switch design; consult the vehicle's service manual. | Knowing the expected resistance values can help identify faulty components. |
| Alternative Names | Mirror Switch 5V Reference Open Circuit, Mirror Control Circuit Open. | Different manufacturers may use slightly different terminology. |
| Common Causes | Wire damage, connector corrosion, faulty mirror switch, ECM/BCM failure (rare). | These are the most frequent culprits behind the B2346 code. |
| ECM/BCM Involvement | Usually the ECM or BCM provides the 5V reference voltage; internal failure is uncommon but possible. | The control module acts as the source of the reference voltage. |
| Testing Methodology | Use a multimeter to check for 5V at the mirror switch connector and continuity along the reference wire. | This helps to pinpoint the location of the open circuit. |
| Circuit Type | Low-current, low-voltage DC circuit. | Understanding the circuit characteristics is important for proper troubleshooting. |
Detailed Explanations
DTC Definition: The B2346 code specifically identifies an open circuit within the 5V reference voltage supply line to the mirror switch. This means the electrical connection is broken, preventing the proper voltage from reaching the switch.
Affected System: The power mirror system is directly impacted, rendering the driver and/or passenger side mirrors inoperable. The mirrors will not respond to any switch inputs.
Symptoms: The primary symptom is the inability to adjust the power mirrors. Depending on the vehicle's design, other electrical systems relying on the same reference voltage might also experience malfunctions.
Voltage Reference: The 5V reference voltage is a stable power supply provided by the ECM or BCM. It acts as a baseline voltage that the mirror switch uses to interpret the driver's input signals.
Wiring Diagram Location: Vehicle-specific wiring diagrams are essential for tracing the circuit and locating potential fault points. These diagrams are typically found in repair manuals or online databases like Alldata or Mitchell OnDemand.
Connector Pinouts: Connector pinouts provide the exact location of each wire within the connector. This information is vital for accurate voltage testing and troubleshooting.
Tools Required: A multimeter is necessary for measuring voltage and continuity. A terminal test kit aids in accessing small connectors. Wire strippers and crimpers are needed for wiring repairs. Electrical contact cleaner helps remove corrosion. A diagnostic scan tool can be helpful, though not always essential for this specific code.
Diagnostic Procedure Steps: The diagnostic process begins with a visual inspection of the wiring and connectors. Then, voltage testing is performed at the mirror switch connector to check for the presence of the 5V reference voltage. Continuity testing of the wiring harness helps identify breaks in the circuit. If a faulty component is identified, it should be replaced.
Common Failure Points: The mirror switch connector is a common failure point due to frequent use. The wiring harness near the door hinge is susceptible to damage from repeated opening and closing of the door. The ECM/BCM connector can also be a source of problems, although less frequently.
Potential Related DTCs: The presence of other DTCs related to the power mirror system, ECM/BCM, or reference voltage circuits can provide valuable clues about the underlying cause of the B2346 code.
Impact on Vehicle Operation: The inability to adjust the mirrors is an inconvenience and can potentially create a safety hazard due to limited visibility, especially in situations requiring quick adjustments.
Repair Verification: After completing the repair, it's crucial to verify that the mirrors are functioning correctly. Clear the DTC from the vehicle's computer and perform a test drive to ensure the issue is resolved and the code does not return.
Reference Voltage Function: The reference voltage serves as a stable and consistent power source for the mirror switch. It ensures that the switch can accurately interpret the driver's input and send the correct signals to the control module.
Open Circuit Location: The open circuit can be located anywhere along the 5V reference wire between the ECM/BCM and the mirror switch. This could be a broken wire, a corroded connector, or a faulty component within the circuit.
Potential for Intermittency: Intermittent issues are possible, especially if the problem is caused by loose connections or vibration. The fault might appear and disappear depending on the vehicle's movement and environmental conditions.
Component Resistance Values: The expected resistance values for the mirror switch and related components vary depending on the vehicle and the specific design of the switch. Refer to the vehicle's service manual for accurate resistance specifications.
Alternative Names: The B2346 code may be referred to by slightly different names depending on the vehicle manufacturer. Common alternatives include "Mirror Switch 5V Reference Open Circuit" or "Mirror Control Circuit Open."
Common Causes: The most frequent causes of the B2346 code include wire damage, connector corrosion, a faulty mirror switch, and, less commonly, ECM/BCM failure.
ECM/BCM Involvement: The ECM or BCM typically provides the 5V reference voltage. While internal failure of these modules is rare, it is a possibility that should be considered, especially if other diagnostic tests fail to identify the root cause.
Testing Methodology: The primary testing method involves using a multimeter to check for the presence of 5V at the mirror switch connector and to perform continuity testing along the reference wire. This helps pinpoint the location of the open circuit.
Circuit Type: The circuit involved is a low-current, low-voltage DC circuit. Understanding these characteristics is important for proper troubleshooting and avoiding accidental damage during testing.
Frequently Asked Questions
What does the B2346 code mean? It indicates an open circuit in the 5V reference voltage supply to the mirror switch, preventing the power mirrors from functioning correctly.
What are the symptoms of a B2346 code? The main symptom is the inability to adjust the power mirrors using the switch.
What causes the B2346 code? Common causes include a broken wire, corroded connector, or a faulty mirror switch.
How do I fix a B2346 code? Troubleshooting involves inspecting the wiring, testing voltage and continuity, and replacing any faulty components.
Can a faulty ECM/BCM cause this code? While rare, a faulty ECM/BCM can be the cause if it fails to provide the 5V reference voltage.
Is the B2346 code a serious problem? While it doesn't directly affect engine performance, it's an inconvenience and potential safety hazard due to the inability to adjust mirrors.
Do I need special tools to diagnose this problem? A multimeter is essential, and a terminal test kit can be helpful for accessing small connectors.
Where can I find a wiring diagram for my vehicle? Wiring diagrams are typically found in vehicle-specific repair manuals or online databases like Alldata or Mitchell OnDemand.
Conclusion
The B2346 DTC signifies a problem with the power mirror system's reference voltage circuit. By systematically diagnosing the circuit, testing components, and repairing any identified faults, you can restore the functionality of your power mirrors and ensure safe vehicle operation.