Introduction:
The diagnostic trouble code (DTC) B2347 indicates a problem within the vehicle's mirror switch circuit, specifically related to the reference voltage. This code often points to a low voltage condition within the positive common supply for the mirror switch, impacting its ability to function correctly. Understanding the causes, symptoms, and troubleshooting steps associated with B2347 is crucial for effectively diagnosing and repairing this issue, ensuring proper mirror control.
| Topic | Description | Possible Causes |
|---|---|---|
| B2347 Definition | Mirror Switch Reference Voltage Positive Common Supply Low Voltage. Indicates the control module has detected low voltage on the reference voltage circuit for the mirror switch. | Low Battery Voltage: Insufficient voltage supplied to the vehicle's electrical system. Faulty Wiring/Connectors: Damaged, corroded, or loose wiring and connectors in the mirror switch circuit. Faulty Mirror Switch: Internal short or open circuit within the mirror switch itself. Faulty Control Module: (Rare) Failure of the body control module (BCM) or other relevant control module responsible for supplying the reference voltage. Short to Ground: A short circuit in the reference voltage wire causing a voltage drop. Excessive Load on Circuit: Too many components drawing power from the same reference voltage circuit. |
| Symptoms | Observable problems resulting from the B2347 code. | Non-Functional Mirrors: The most common symptom; mirrors may not adjust in any direction. Intermittent Mirror Operation: Mirrors may work sporadically or only in certain directions. Other Electrical Issues: Potentially other electrical components that share the same reference voltage circuit may malfunction. Mirror Control Module (MCM) faults |
| Affected Components/Circuits | Components and circuits directly related to the fault. | Mirror Switch: The primary component responsible for mirror adjustments. Wiring Harness: The wiring connecting the mirror switch to the control module. Connectors: Electrical connectors joining the wiring harness to the mirror switch and control module. Body Control Module (BCM) / Control Module: The module providing the reference voltage and processing mirror switch signals. Reference Voltage Circuit: The specific wire and associated components providing the reference voltage for the mirror switch. |
| Diagnostic Tools | Tools used to diagnose and troubleshoot the B2347 code. | Multimeter: Used to measure voltage, resistance, and continuity in the circuit. Scan Tool: Used to read and clear DTCs, and potentially access live data from the control module. Wiring Diagram: Essential for understanding the circuit layout and identifying potential problem areas. Test Light: A simple tool to check for power and ground in the circuit. |
| Troubleshooting Steps | Ordered steps to follow when diagnosing and repairing the B2347 code. | Visual Inspection: Inspect wiring, connectors, and the mirror switch for damage or corrosion. Voltage Testing: Measure the voltage at the mirror switch connector and at the control module to identify voltage drops. Continuity Testing: Check the continuity of the wiring between the mirror switch and the control module to identify open circuits. Resistance Testing: Measure the resistance of the mirror switch to check for internal shorts or opens. Component Testing: Test the mirror switch and control module using a multimeter or specialized tester (if available). Circuit Load Testing: Check if the circuit is overloaded by other devices. |
| Potential Fixes | Solutions to resolve the B2347 code. | Repairing/Replacing Wiring: Repair or replace damaged or corroded wiring. Cleaning/Replacing Connectors: Clean or replace corroded or loose connectors. Replacing Mirror Switch: Replace the faulty mirror switch. Repairing/Replacing Control Module: (Rare) Repair or replace the faulty control module (BCM). Addressing Short to Ground: Locate and repair the short circuit. Resolving Overload: Remove excess load from the circuit. |
| Related DTCs | Other DTCs that may occur in conjunction with B2347. | Other Mirror Switch Codes: Codes related to specific mirror functions (e.g., mirror up/down circuit malfunction). Voltage Related Codes: Codes indicating general voltage issues within the vehicle's electrical system. BCM Codes: Codes indicating problems with the body control module. LIN Bus Communication Errors |
| Reference Voltage Value | The typical voltage expected on the reference voltage circuit. | Typically 5 Volts DC, but can vary depending on the vehicle manufacturer and system design. Consult the vehicle's service manual for the specific value. |
| Positive Common Supply | The nature of the positive supply shared by multiple circuits. | A single positive voltage source that is distributed to multiple components, simplifying wiring and reducing the number of connections. A failure in this common supply can affect multiple systems. |
Detailed Explanations
B2347 Definition: The B2347 DTC, "Mirror Switch Reference Voltage Positive Common Supply Low Voltage," signifies that the vehicle's computer has detected a voltage level below the expected threshold on the reference voltage circuit dedicated to the mirror switch. This reference voltage is crucial for the switch to function correctly, allowing the driver to adjust the side mirrors. The code implies that the control module is not receiving the anticipated voltage signal from the mirror switch, indicating a potential issue within the circuit.
Symptoms: When the B2347 code is present, the most noticeable symptom is usually the inability to adjust the side mirrors. This can manifest as a complete lack of movement in any direction or intermittent operation, where the mirrors only work sporadically. In some cases, other electrical components that share the same reference voltage circuit might also exhibit malfunctions. Mirror Control Module (MCM) itself could also be faulty.
Affected Components/Circuits: The B2347 code directly implicates several components and circuits. These include the mirror switch itself, which is the primary input device for mirror adjustments. The wiring harness connecting the switch to the control module is also a suspect, as are the electrical connectors joining the wiring. The body control module (BCM) or another relevant control module that supplies the reference voltage is a key component. Finally, the reference voltage circuit itself, including the specific wire and associated components, is directly involved.
Diagnostic Tools: To effectively diagnose the B2347 code, several diagnostic tools are essential. A multimeter is crucial for measuring voltage, resistance, and continuity in the circuit. A scan tool allows technicians to read and clear DTCs and potentially access live data from the control module. A wiring diagram is invaluable for understanding the circuit layout and identifying potential problem areas. A simple test light can be used to quickly check for power and ground in the circuit.
Troubleshooting Steps: The troubleshooting process for B2347 involves a systematic approach. First, a visual inspection of the wiring, connectors, and mirror switch is crucial to identify any obvious damage or corrosion. Next, voltage testing should be performed at the mirror switch connector and at the control module to identify any voltage drops. Continuity testing of the wiring between the switch and the module can help identify open circuits. Resistance testing of the mirror switch can reveal internal shorts or opens. Finally, component testing of the mirror switch and control module (if possible) can help pinpoint the faulty component. It is also important to conduct circuit load testing to ensure that the circuit is not overloaded by other devices.
Potential Fixes: The solutions to resolve the B2347 code depend on the root cause. Repairing or replacing damaged wiring is a common fix. Cleaning or replacing corroded connectors can also resolve the issue. If the mirror switch is faulty, replacing it is necessary. In rare cases, repairing or replacing the control module (BCM) might be required. Addressing any short circuits to ground and resolving any overload conditions on the circuit are also potential fixes.
Related DTCs: The B2347 code may sometimes be accompanied by other related DTCs. These may include other mirror switch codes related to specific mirror functions, voltage-related codes indicating general voltage issues, or BCM codes indicating problems with the body control module. LIN Bus Communication Errors could also be present if the mirror switch communicates via the LIN bus network.
Reference Voltage Value: The expected voltage on the reference voltage circuit is typically 5 Volts DC. However, this value can vary depending on the vehicle manufacturer and the specific system design. It is crucial to consult the vehicle's service manual to determine the precise reference voltage value for the particular vehicle model and year.
Positive Common Supply: The "positive common supply" refers to a single positive voltage source that is distributed to multiple components within the vehicle. This design simplifies wiring and reduces the number of connections required. However, a failure in this common supply can affect multiple systems, making it crucial to diagnose the root cause accurately. The positive common supply provides a stable and reliable voltage source for various sensors and actuators throughout the vehicle.
Frequently Asked Questions
What does the B2347 code mean? It indicates a low voltage issue on the reference voltage circuit for the mirror switch.
What are the most common symptoms of B2347? The most common symptom is the inability to adjust the side mirrors.
How do I diagnose the B2347 code? Use a multimeter to check voltage and continuity in the mirror switch circuit.
What is the typical reference voltage value? Typically 5 Volts DC, but consult the service manual for specific values.
Can a faulty mirror switch cause this code? Yes, an internal short or open circuit in the mirror switch can trigger B2347.
Is it possible the BCM is causing this? Yes, although less common, a faulty BCM can cause this issue.
What if the wiring is damaged? Repair or replace any damaged or corroded wiring in the circuit.
Conclusion
The B2347 DTC signals a low voltage condition in the mirror switch reference voltage circuit, leading to impaired or non-functional mirror adjustments. By systematically following the diagnostic steps and addressing the potential causes, such as wiring issues, a faulty mirror switch, or a malfunctioning control module, the problem can be effectively resolved, restoring proper mirror functionality. Always refer to the vehicle's service manual for specific voltage values and troubleshooting procedures.