guenterroth4
Toyota iQ Auxiliary Heater Issue
Summary of the thread
A 2012 Toyota iQ owner is facing an issue with the auxiliary heater, which fails to activate and shows a generic 'Auxiliary Heater Malfunction' error. Initial checks of fuses and coolant levels showed no issues, leading to a suspicion of a glow plug problem. Suggestions included checking the voltage at the glow plug and considering professional repair due to the complexity of accessing the component. Ultimately, a workshop confirmed a defective glow plug, resolving the issue.
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4 comment(s)
guenterroth4 (community.author)
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?
laura_koch2
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.
guenterroth4 (community.author)
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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TOYOTA
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IQ
laura_koch2
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.