B1522

Hood Switch Circuit Short To Ground

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

In plain language — no jargon

The hood switch circuit is shorted to ground, meaning the electrical wire is touching metal and creating an unwanted connection. It's like a light switch stuck in the 'on' position because the wires are touching each other.

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Symptoms You May Notice

3 known symptoms for this code
Hood ajar warning light stays on continuously
Dashboard warning message displays even with hood closed
Potential interior light malfunction or incorrect dome light behavior
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How Your ECU Detects This

Technical sensor logic and voltage thresholds

The ECU monitors the hood switch voltage signal, expecting high voltage when the hood is closed and low voltage when open. A short to ground causes the signal to drop to 0V continuously, triggering a fault code regardless of actual hood position.

Voltage & Parameter Thresholds

ParameterNormal RangeFault Condition
Hood Switch Voltage 12V (closed) to 0V (open) Continuous 0V or below 0.5V when hood is closed
Signal Detection Time Responds within 100ms to hood state change No voltage change detected; stuck at ground
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Diagnostic & DIY Fix Guide

Check these in order — from cheapest to most complex
1
Wiring harness and connectors
Inspect the hood switch wiring for damaged insulation or pinched wires touching the vehicle frame and repair or tape exposed sections.
2
Hood switch connector
Disconnect and reconnect the hood switch connector under the hood latch to ensure proper seating and eliminate corrosion.
3
Hood switch assembly
Replace the hood switch if the connector is secure and wiring is intact, as the internal contacts may be permanently shorted.
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When to See a Professional Mechanic

Not all fault codes are safe to DIY

Code B1522 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 B1522

What happens after you fix the fault

Once the fault is repaired, B1522 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.