2006 Impala LT 3500 engine. 97,000 miles.
It had a code P0172 (Bank one rich) Checked front spark plugs, cleaned MAF, checked fuel pressure (60psi) It runs great. I thought I had a bad downstream oxygen sensor...it barely moved on the scanner. Changed it, and reset all codes with the scanner.
Now when I drive it to get the monitors ready, (Htr, Cat, Evap, O2) I get no responce. I know the drive cycles, but it seems to not want to budge. It does go into closed loop, and the data looks good.
I've got around 60 miles into it, after the re-set.
Could I be looking at a re-flash? Any ideas???
So far, no check engine light, ....yet...
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Welcome to the forum. It's not how many miles but number of drive cycles under various conditions that matter. It may take 2 to 6 trips before all the OBD readiness tests are complete. Unless you have pending trouble codes, there's nothing you can do but wait, err, drive.
I have worked on other GM's and in a similar situation, have had to clear codes and drive. Usually the Htr monitor is the first to go ready. I start it cold, apply the headlights, heater, and rear defrost and let it warm up. Then I drive it, hold around 45 to 50 mph for 5 miles or more with 1/4 to 3/4 tank full. I do the coast to zero and then let it sit.
Anyways....I almost always get one monitor to clear by this point, if not all, ...but this won't budge.