lilianwilliams5
Active Hood Fault Volvo S40
Summary of the thread
A 2005 Volvo S40 displayed an "Active hood fault" message and an airbag warning light, with the spring actuators for the hood triggering without impact. The issue was suspected to be a faulty acceleration sensor. Suggestions included checking wiring and connectors for loose or corroded connections and inspecting the hood latch mechanisms. Ultimately, it was advised to seek professional diagnosis due to the complexity and safety implications, leading to the identification and replacement of the defective acceleration sensor.
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4 comment(s)
lilianwilliams5 (community.author)
Good point about the wiring and connectors. I'll give them a look. Is there a way to test the acceleration sensor itself, maybe with a multimeter? Or do I just replace it?
marvinbraun3
Testing the sensor directly with a multimeter is tricky without knowing the specific resistance values and expected outputs. Given that the actuators have deployed and the system is throwing a fault, and considering the potential safety implications of a malfunctioning active hood system, I'd recommend taking it to a trusted workshop for a proper diagnosis. They'll have the diagnostic tools and expertise to pinpoint the exact cause and ensure the system is functioning correctly.
lilianwilliams5 (community.author)
Yeah, that makes sense. I was hoping to avoid the workshop, but I guess messing with safety systems isn't the best idea. It was indeed the acceleration sensor that was defective. Repair cost including parts was 315€. Thanks for the advice!
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VOLVO
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S40
marvinbraun3
Interesting issue. If the actuators triggered without an impact, and you're getting a fault code, a faulty acceleration sensor is possible. Have you checked the wiring and connectors to the sensor? A loose or corroded connection could trigger a false reading. Also, inspect the hood latch mechanisms for any signs of binding or damage. It's worth a look before condemning the sensor.