Toyota iQ Auxiliary Heater Issue

I'm experiencing an issue with the auxiliary heater in my 2012 Toyota iQ (gasoline engine) with 121837 km on the clock. The parking heater simply refuses to activate. I've plugged it into a diagnostic tool and it's throwing an error. I've checked the basic fuses and coolant level, but everything seems fine. I suspect it might be related to the glow plug, but I'd appreciate any insights before I start tearing things apart.

4 comment(s)

Glow plug is a very common culprit for auxiliary heater issues on Toyotas, especially with that mileage. Is the error code specific to the glow plug circuit, or is it a more generic heater malfunction code? Have you tried checking the voltage reaching the glow plug when the heater attempts to start? A multimeter would be handy for that.

Thanks for the quick reply! The error code is a bit vague, something along the lines of 'Auxiliary Heater Malfunction'. I haven't checked the voltage at the glow plug yet, good point. Where exactly is the glow plug located? Is it easy to access, or do I need to remove a bunch of other components first?

That generic code unfortunately doesn't nail it down. Accessing the glow plug on the iQ auxiliary heater can be a bit fiddly, usually buried near the firewall. Given the vague error and the potential hassle of reaching the plug, honestly, for that kind of electrical issue, a workshop visit might be wisest. Could be a faulty control unit as well.

Thanks for the advice! I suspected it might be a bit more involved than a simple fix. I'll take it to the shop. They confirmed it was a defective glow plug and the repair, including labor, came to 440€. Appreciate the help!

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