help , have 97,700 miles on jeep, today out of blue CHECK ENGINE LIGHT - came on, does light come on after so many miles so it can be serviced? or is there rally a problem?
how do I read the codes? or reset light or where do I start to locate problem any Ideas any tips ??? casca at core.com use the @ when emailing me thanks casca
12 == normal battery disconnect code that resets after a god awful number of starts. Usually ignored. (check/clean the battery terminals anyway) 21 == O2 sensor (upstream) i.e. before the cat. Time to get a new one. My fav OEM parts counter is buymopar.com (a dealer but without the dealer price gouging)
The light will reset once the O2 sensor is fixed.
The 12 code will clear itself only after about 50 starts, that's why it's generally ignored unless there are a lot of other error codes being thrown out. It sets every time you disconnect the battery.
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