2004 Golf, manual transmission. The yellow check engine light comes on when it’s driven on the highway for more than 10 miles or so (60-70 mph).
The light goes off on it’s own after about 36 hours of suburb driving - 1-2 miles at a time on suburb roads, lots of lights and not going over 40 mph.
Any ideas on why the light is coming on? No other signs of trouble occur - oil looks good, temp stays fine, no smells, etc.
Any ideas on why the light goes off after 4-6 miles/36hours?
My guess is the cat is heating up. You may need a new one. But there’s no reason to guess, take it to a shop or auto parts store and get the diagnostic codes read. Then you will be working with objective data, not guesses.
Thanks for the response, that’s the next step. I thought I’d see if this was a known issue or not.
There are about 1,000 reasons that light can come on so the codes come first. Note that when the light goes off, it might get scanned and turn up nothing. Many auto parts stores will read codes for free - but make sure you drive in with the light still on. And if you want to post back for comment post the exact code (like “P0123”) rather than what someone said it means. They probably don’t even know what it means.
Looking around it seems that you can buy an OBD2 scanner for $20-40. Is it worth it to have one myself?