Questions and Answers

Plymouth Breeze Codes 12, 17 And 21 Q. Vincent, I've recently purchased a 1997 Plymouth Breeze, 2.0 Liter, Automatic Transmission, 67,000 miles. The car drives good, however, I intermittently see the "Check Engine" light come on. I've retrieved the codes (using my key) and it gives me the following 12, 21, 12 and 17. Are these at all related?

Where would you start, to resolve these errors? and is there a way to reset these errors to make sure they are new? Any guidance would be much appreciated!

Thanks,
Tom

A. Code 12, in this case, is used as a divider between codes. The code 17 is: "Closed Loop Temperature not reached" or "Engine too cold too long". The "P" code would be more specific. In either case this code points to a bad thermostat. It's probably stuck open and it's taking too long for the engine to get to normal operating temperature.

Code 21 indicates a problem with either the Downstream or the Upstream HO2S. Again, a "P" code would be more specific. Either one could be open, shorted, slow to respond or not showing any change at all.

There could also be a problem with the connectors for the HO2S, so that would be the first thing to check.