1998 Lexus ES 300

Computer problem
1998 Lexus ES 300 6 cyl Two Wheel Drive Automatic 120, 00 miles

I have a 1998 Lexus ES300 with over 120,000 miles. Runs mint! About 7,000 miles ago I threw a O2 sensor code (Bank 2 Sensor 1). Fixed it with an OEM sensor. Cleaned the codes etc. CEL light off and then drove since August (no issues).

Within the 7,000 miles I have no MIL/DTC codes etc. Again car runs mint, great mpg etc.

The question I have is on the scanner there are 3 lights (red, yellow, green). Red is something is wrong (will throw code), yellow means ECM has NOT run a full diagnostics on engine (with related blinking system)and green means 100% systems have run. My car is again running fine but I still get a yellow light and on the IM screen I get a blinking CAT. That means the CAT has not been tested via the ECM. This model car does not check the CAT per say. It uses the O2 sensor before/after to sense the CAT.

So what is up. ECM issue, scanner (latest firm is downloaded)…. Got me puzzled.
February 28, 2008.

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