I have a 1998 DI with 150k on the clock. Recently all four O2 sensors were replaced and the ECM was reset to clear the codes the old [bad] O2 sensors were throwing. I've gone to have the Disco tested at an Illinois Air Team inspection facility twice - failing both times. The inspection report says that the Catalytic Converter, Evaporative Control System and Oxygen Sensor system monitors are all "Not Ready". What can I do to correct this issue?

Thanks.

 

I'm not sure, but it sounds like you have not driven the truck enough. I was told you have to drive for 50 miles before you can get tested.

My mechanic gave me an instruction sheet to follow before smog testing that does it quicker than 50 miles, but it's pretty precise. Search on the internet for the process. I don't have it anymore.

 

I been told that also, drive it

 

As one who needed to go through these emissions tests, I found the secret is to run your tank low, then fill it with fresh premium & (2) cans of dry gas. Failed the first try, but was told to do the above & it passed with flying colors with no additional steps taken. Went through the process for years & never failed again...

 

Dry gas?

 

I just did my emission test last week, failed once and then got it to pass. If you found one of my posts, I still got the P1318 issue which still hasn't got resolved yet.

What I did was I use an OBD2 dongle and Torque Pro on my smartphone and I can see if the monitors are ready or not. Almost all handheld OBD2 scanners could also see the monitor readiness as well.
The dongle was about $10 and Torque Pro was $5.

In short, like what the above posters are saying, you need to drive more to get it "ready".

On mine, I drove the Disco with the Torque Pro hooked up and I noted when the monitors are ready and when the faults are logged. I drove it for about a week and learned their pattern.

First, find out if your emission test allows any "not ready" monitors.
My 1998 Disco got these monitors:
1. Misfire
2. Fuel System
3. Components
4. Catalyst
5. Evap
6. O2 sensor
7. O2 sensor heater

Here in Ontario, Canada, our test is very similar to California's emission test and for a 1998 vehicle, we are allowed to have two "not ready" monitors and still will pass. If the check engine light(CEL) is lit, test fail right away. They changed the system from tailpipe emission test to OBD2 compliant test last year. All they do is rely on the OBD2 to tell them if the car's emission system is working or not. For older vehicles, they still do tailpipe test.
Check with your state's emission regulations and see what is allowed.

There are two types of fault codes: Pending fault code, Logged fault code.
A Pending fault will not cause the Check Engine Light to be lit. The Logged fault code will light up the CEL. Also note that even if you got a Pending fault, it takes about two engine start cycles to turn it into a Logged fault. Therefore, if you know your car got a Pending fault(mine got P0430 catalytic converter bank 1 efficiency low and the P1318 Rough road signal high fault), clear the fault, drive it, when the monitors are ready, bring it to the emission test facility right away and don't shut it down and restart. Leave the truck running for the emission guy and let him do the shutdown and restart. Hopefully within the short time(engine still hot), the Pending fault won't turn into a Logged fault.

Everytime I cleared the fault codes, the monitors #1(Misfire),#2(Fuel system), #3(Components) were ready pretty well right away. I haven't recall seeing these three monitors ever been not ready. #6 (O2 sensor) and #7 (O2 sensor heater) were next to be ready. #5 (Evap) and #4 (catalysts) were the last to be ready.

This is exactly what I did for the test which passed:
1. I warmed up the Disco.
2. I cleared all the fault codes(pending and logged) while the engine is running.
3. I drove it in stop and go traffic for about 40 minutes(about 20 miles).
4. Drove it at highway speeds for about 5 minutes.
5. Drove to the test center directly and did not shut off the truck.(All monitors were ready and no pending or logged fault yet).
6. Emission tester drove the truck into the shop and shut it off.
7. Emission tester plugged in their OBD2 equipment and then started the truck.
8. Passed!
9. When I picked up the truck after the test, the Pending fault (P1318) showed up, but test is done so doesn't matter anymore.

Hope this helps!

 

Yep, got it from O'Rileys (their brand).

 

Update: Had a friend hook up his code reader to the Disco. The computer says the circuits are "open" or the "impedance is high" on both of the upstream O2 sensors. Maybe the shop didn't install them properly? Any ideas?

Thanks.