B2491

RF PARK LAMP OUTPUT CIRCUIT Short to Battery

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

In plain language — no jargon

The right front park lamp circuit is shorted directly to battery power, causing excessive voltage that the ECU cannot control. It's like a wire touching the positive battery terminal directly instead of going through the proper switch.

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Symptoms You May Notice

3 known symptoms for this code
Right front park lamp stays on continuously or is too bright
Right front park lamp does not respond to lighting controls
Dashboard warning light illuminated; possible electrical burning smell
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How Your ECU Detects This

Technical sensor logic and voltage thresholds

The ECU monitors the park lamp output circuit voltage and current draw through a dedicated driver module. When the circuit shorts to battery (12V+), the voltage remains at battery potential instead of the controlled PWM signal, triggering the fault. The ECU detects this abnormal high voltage condition that exceeds safe operating thresholds.

Voltage & Parameter Thresholds

ParameterNormal RangeFault Condition
Park Lamp Output Voltage 0-12V (PWM controlled, typically 5V average) Constant 12V+ (short to battery detected)
Park Lamp Current Draw 0.5-2.0 Amps nominal >3.0 Amps sustained (overcurrent condition)
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Diagnostic & DIY Fix Guide

Check these in order — from cheapest to most complex
1
Wiring harness connector (RF park lamp circuit)
Inspect and reseat the park lamp wiring connector at the lamp housing to eliminate loose contact causing intermittent shorts.
2
Park lamp bulb and socket assembly
Replace the right front park lamp bulb and socket as internal short or damaged socket insulation commonly causes this fault.
3
Wiring harness (RF park lamp to body)
Inspect the full wiring run for damaged insulation or pinched wire; repair or replace compromised sections to eliminate short to vehicle frame.
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When to See a Professional Mechanic

Not all fault codes are safe to DIY

Code B2491 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 B2491

What happens after you fix the fault

Once the fault is repaired, B2491 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.