Incomplete Monitors

PREATORIAN

MEMBER
2000 CHEVROLET ASTRO
6 CYL
4WD
AUTOMATIC
110,000 MILES

About a month ago I was driving along and experienced a check engine light in my 2000 Chevy Blazer. I used my own computer to check the problem and it came up as an "EVAP Purge Solenoid". I googled that and discovered that the solenoids get stuck sometimes and quite often unstick themselves. So I wiped the computer and the light never came back on.

Three weeks later I went for an inspection and discovered that a whole bunch of the on board OBD2 sensors were incomplete. EGR, Catalytic Converters, Evap system, and some other one which I forgot. O2 monitors are working.

After the initial wipe, I put 250 miles on the car. Then I wiped it again and since then I've put on another 350. I've also done at least a dozen different drive cycles recommended to engage the monitors.(Most involving letting the car idol, accelerating to 55 for a few minutes, then coasting to a halt without breaks).

At this point I dont know what else to do. I've taken it to a mechanic and he was just as stumped as I. Does anyone know what the problem could be? Or how I can get another two of these stupid monitors to respond(without more drive cycles)?

1 Reply

HMAC300

MECHANIC
48,601 POSTS

The only thing I can think of is that the ground is bad for the pcm or engine ground. You may have wiped something out in the pcm as well and it may need reprogramming. I am assuming that you have checked the fuses int he i/p and underhood. Ther is a ground by the battery that screws on to the firewall and that may be dirty causing this. Other than that it's puzzling.