An operation called CarMD compiles each year something it calls the Vehicle Health Index, which is derived from repair statistics stemming from the appearance of the dreaded Malfunction Indicator Light, known familiarly as the “Check Engine” light. Since I have reason to fear this horrid little device I joke, or at least I claim it’s a joke, that every time I see it, it costs me $600 I figured I’d look at their report [pdf] and see what sort of dire catastrophes have befallen my fellow Glorified Nissan owners.
For the year ending 30 September 2013, CarMD reports that the single most common cause of the MIL on an Infiniti is a bad ground wire, which costs essentially nothing for parts and about $170 for labor. This revelation is sort of disheartening. And the fourth is the failure to tighten the gas cap adequately, which, assuming the cap is okay, costs zilch, though the tech is likely to snicker.
The three remaining in the top five, I’ve had to endure in the past seven years: bad ignition coils ($290, assuming you didn’t have to replace all six), bad oxygen sensors ($360, assuming ditto), and catalytic-converter replacement, which allegedly one might have avoided with a little attention to those oxygen sensors ($1190). A check of other brands indicates that bad cats typically run over a grand, and the domestics are a hair less than the imports.
Various GM models, though, seem to run into problems that require this solution: “Remove Aftermarket Alarm System.”
As to where they get this (these?) data, CarMD says they collect it from their network of ASE-certified techs, which seems reasonable to me. In all, they say, Hyundai rules: Toyota has just as few repairs, but fixing the Toyotas costs more.