B2348

Mirror Switch Reference Voltage Positive Common Supply Voltage Fault

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

In plain language — no jargon

The mirror control system isn't receiving proper electrical power from the main supply, similar to a lamp that flickers because the outlet connection is loose. The ECU detects the voltage feeding the mirror switches has dropped below acceptable levels.

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Symptoms You May Notice

3 known symptoms for this code
Power mirrors not functioning or responding intermittently
Mirror adjustment buttons unresponsive or delayed
Dashboard warning light or fault indicator illuminated
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How Your ECU Detects This

Technical sensor logic and voltage thresholds

The ECU monitors the positive supply voltage rail dedicated to the mirror switch circuit. It compares the measured voltage against expected thresholds to detect drops caused by wiring faults, loose connections, or power distribution failures. When voltage falls below the minimum acceptable range, the fault code triggers.

Voltage & Parameter Thresholds

ParameterNormal RangeFault Condition
Mirror Supply Voltage 11.5-14.5V <10.5V or intermittent dropout
Voltage Stability Steady, <0.5V ripple Fluctuating or unstable supply
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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 posts and tighten all battery cable connections to restore full voltage delivery.
2
Mirror switch wiring harness
Inspect and reseat the connector at the mirror switch module for loose pins or corroded contacts.
3
Fuse and relay for mirror circuit
Check the dedicated mirror control fuse and relay in the fuse box; replace if burnt or corroded.
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When to See a Professional Mechanic

Not all fault codes are safe to DIY

Code B2348 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 B2348

What happens after you fix the fault

Once the fault is repaired, B2348 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.