fabianphoenix1
iQ Overheating Issue
Summary of the thread
A 2010 Toyota iQ is experiencing overheating issues, with the check engine light on. Diagnostics suggest a defective radiator fan, potentially due to a faulty speed sensor. A similar issue in another vehicle was resolved by checking the thermal switch and fan motor. It is recommended to test these components before replacing the speed sensor. Ultimately, the problem was confirmed to be the speed sensor, which was repaired at a cost.
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4 comment(s)
fabianphoenix1 (community.author)
Thanks, that's helpful. How did you or your mechanic test the thermal switch and fan motor? What steps did you take to diagnose them?
elizabethwolf11
My mechanic used a multimeter to check the thermal switch's continuity at different temperatures. They powered the fan motor directly to see if it would spin. Given your Toyota's mileage and the symptoms, check those before focusing on the speed sensor. I'd suggest a workshop visit.
fabianphoenix1 (community.author)
Thanks for the explanation. I'll get the thermal switch and fan motor checked before replacing the speed sensor. It's best to check everything first. It was the speed sensor and cost 250€ to repair.
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TOYOTA
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IQ
elizabethwolf11
I had almost the same thing with my 2012 Opel Corsa: overheating and the check engine light. For me, it was a bad thermal switch that wasn't regulating the temperature, so the fan wouldn't turn on. Before you replace the speed sensor, check the thermal switch and the fan motor itself. You can test them separately.