B2347

Mirror Switch Reference Voltage Positive Common Supply Low Voltage

Body Chassis/Safety Mirror Control 🟢 Low — Fix at next service ✅ Safe to Drive
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What This Actually Means

In plain language — no jargon

The power supply voltage to your mirror switch control circuit has dropped too low, similar to a dimming lightbulb caused by a weak battery connection. The ECU detected that the positive reference voltage is below the minimum threshold needed to operate the mirror adjustment switches properly.

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Symptoms You May Notice

3 known symptoms for this code
Mirror adjustment buttons not responding or working intermittently
Mirror control functions disabled or erratic behavior
Warning light or fault code displayed on dashboard
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How Your ECU Detects This

Technical sensor logic and voltage thresholds

The ECU monitors the positive reference voltage supplied to the mirror switch circuit. This voltage must remain within specification to ensure proper switch signal detection. When the voltage drops below the minimum threshold, the ECU cannot reliably read switch inputs and triggers this fault code.

Voltage & Parameter Thresholds

ParameterNormal RangeFault Condition
Mirror Switch Reference Voltage 11.5V to 14.5V Below 10.5V or unstable
Supply Current Draw Under 5A steady state Excessive draw or dropout
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Diagnostic & DIY Fix Guide

Check these in order — from cheapest to most complex
1
Battery terminals and connections
Clean corrosion from battery terminals and tighten all connections to ensure solid ground and positive feed to the mirror circuit.
2
Fuse for mirror control circuit
Locate the mirror fuse in the fuse panel, inspect for discoloration or damage, and replace with correct amperage rating if needed.
3
Mirror switch assembly or wiring harness
Inspect the mirror switch connector and wiring for corrosion, loose pins, or damaged insulation and repair or replace as necessary.
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When to See a Professional Mechanic

Not all fault codes are safe to DIY

Code B2347 is a low-severity fault. Your vehicle is generally safe to drive to a workshop for diagnosis. However, do not ignore it indefinitely — low-severity codes often indicate developing problems that become expensive if neglected. Book a diagnostic appointment within 2–4 weeks. If you notice any additional symptoms (rough running, power loss, unusual smells), treat it as higher priority.

Safety note: OBD-II codes identify the system or circuit where a fault was detected — they do not always identify the exact failed component. A professional mechanic using live sensor data will diagnose the root cause more accurately than replacing parts based on the code alone.
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How to Clear Code B2347

What happens after you fix the fault

Once the fault is repaired, B2347 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.

The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.

✅ Safe to Clear When
  • Fault has been diagnosed and repaired
  • You want to confirm the repair worked
  • Code appeared after a sensor was cleaned
⚠️ Do Not Clear When
  • Preparing for an emissions/PUC test
  • Root cause is still undiagnosed
  • Check engine light is flashing
Emissions test note: Clearing codes resets OBD readiness monitors. Most vehicles need 50–100 km of mixed driving before monitors complete. Do not clear codes immediately before an emissions or PUC inspection.