The dash gauge is not involved with the Engine Computer. In the early '90s there was nothing to "reset". That is a holdover from mechanics becoming accustomed to disconnecting the batteries to force the computers to relearn data. GM had a lot of trouble with Engine Computers and this was a common practice although it was rarely a permanent fix. This wasn't a problem on Fords or other car brands.
When you DO disconnect the battery, the Engine Computer has to relearn the characteristics of all the sensors and it has to rebuild the fuel trim tables. It does that by comparing many things to each other. When you replace a single sensor, the job of relearning its personality, so to speak, is much easier and faster.
Tuesday, December 23rd, 2014 AT 3:52 PM