Can't pass Emissions (o2 test and Catalyst Tests not ready)

[Brad J]

I have a 2002 Chevy TrailBlazer (192k miles) that I have been trying to get licensed. It hasn't been driven in 8 years due to an small front end accident by the prior owner. Last week I replaced all 6 Coils (ACDelco brand) due to the Service Engine Soon light coming on and throwing P0300 & P0305 (Cylinder Miss fires) codes. I then found the real problem was the Fuel Pressure regulator was pumping fuel into the Air Resonator so it then got replaced. That fixed those codes and I put about 60 miles on it but the Cat test and Evap test were not ready. I started getting a P0440 code so I replaced the Gas Cap and now that code hasn't returned. I cleared the codes and put about 80 miles on it and haven't had any codes. The Evap is now ready but now the 02 and Cat tests are not. My scanner shows o2s not ready but Ho2s is ready. I installed Torque Lite and used a Bluetooth scanner for the 1st time but don't know what I am looking for. Do these look like the 2nd o2 sensor might be worth replacing? Any other things to check or try?
Thanks, Brad

 

[Kiel]

Some times on cats you need to get the exhaust really hot. I would drive on the east side up the bench hills in a high rpm gear back in the day. I've probably had to get 2000 cars ready for emissions back then. Sometimes, resetting the computer and trying again is the best. Just make sure you start it from a cold start

 

[UNSTUCK]

Each vehicle has a certain mileage it needs to become "ready" after a battery disconnect or similar issue. It took like 180 miles for my LJ to reset after a dead battery. And like Kiel said, get it hot and working.

Never disconnect a battery right before an emissions test.

 

[glockman]

This dude is a little weird but super informative. I am an electronics tech and I have learned SOO much from his videos. Watch this one and all his others on 02's/ fuel trims and I'm sure you'll be able to diagnose if your O2's are bad.

 

[Kiel]

I've had vehicles take 15 minutes to get ready from scratch and vehicles that took 4 days

 

[MikeGyver]

Google "2002 Chevy TrailBlazer emissions drive cycle". There are multiple driving conditions that must be met before the computer will perform the emissions self tests. All of you should be doing this for any car you need to get to pass emissions self-tests.
As long as upstream o2 sensors are cycling quickly (from like .2 to .8 or so volts) once fully heated up and cruising then they're probably fine. Downstream o2's should be cycling slower, every few seconds.

 

[gijohn40]

I found on my 06 LJ that the amount of fuel in the tank also had something to do with it. I needed above 1/4 and below 3/4 before the self test would kick in.

 

[Kiel]

Evap wont get ready below 1/2 tank usually

 

[Brad J]

Thanks for the tips guys. I drove it over 60 miles going up to Lagoon and back and then all over by the B in Bountiful going up and down the hills in a lower gear. I ended up getting a P0014 (Camshaft Position Timing over advanced). I replaced the Camshaft Position Actuator Solenoid so that went away. Then yesterday I got a P0128 (Coolant Temp below thermostat regulating temp). I did notice that the Heater didn’t seem to be putting out hot air. I installed a new Thermostat after braking one of the bolts flush with the block. I’m glad that welding a nut on it got it out. I did have to remove the Alternator so the battery got removed during that so I am starting over again. I’ve put over 350 miles on it with the temp tags but I have to keep resetting it due to these codes. I watched that youtube video and now have a favorite Youtube channel to check out. I did fill up on Friday night and I am getting close to ¾ tank so that is good to know about the fuel level. I got and printed out the Driving Cycle. I’m trying to figure out the best place to get up to 55 for 3 minutes and then coast down to 20 then up to 55 for 5 minutes. All while having the engine cold each time. It might pay to park the TrailBlazer there and take another vehicle to the “testing area” each time. I live by Legacy and Redwood Road but neither are ideal for coasting down to 20mph. I’ll give it a try but I think I will need to get another Temporary Permit. Thanks again and I’ll let you know how it goes.

 

[Brad J]

It Passed!!! On Monday I did 3 Jack stand Driveway Driving Cycles having to wait an hour in between each for it to cool down. It still was only showing the 02 test being ready so I wasn't sure if it was going to work or not running it in my driveway. I drove it out to Rose park & walked the dog for about an hour. I then made a good run on the north side of the Airport on 2100 North doing well till an airport PO car pulled out behind me. I decided not to do a coast to 20 & did the best I could turning by DHL. I made a better Driving Cycle on that same road later that night but still only the 02 test was ready. I had another attempt last night but was keeping the speed down due to the snow and ice. I have been driving it to work every day for the last 2 weeks but I think the 1 hour drive to work today in the snow storm did the trick. The Evap test was ready so I ran it in and got it Inspected on the final day of the temp tag. I'm stoked. I have put over 600 miles on the thing in the last 2 weeks getting to this point. Thanks for the help.

 

[Kiel]

Low coolant temp readings can stall most the tests

 

[Spork]

Alright got to ask, took my VW in for emissions to the Jiffy Lube and the guy said something like if it's older than a 2005 it's just a visual inspection, looking at the certificate most of it says N/A and the visual portion has:
Particulate Filter - N/A
Catalytic Converter - Pass
EGR - Pass
SCR - N/A
DEF - N/A
OBDII System - Pass
ECS Tamper - Pass

So did I just pay $39 for a guy to say the light isn't on and looks good?

 

[Brad J]

Alright got to ask, took my VW in for emissions to the Jiffy Lube and the guy said something like if it's older than a 2005 it's just a visual inspection, looking at the certificate most of it says N/A and the visual portion has:
Particulate Filter - N/A
Catalytic Converter - Pass
EGR - Pass
SCR - N/A
DEF - N/A
OBDII System - Pass
ECS Tamper - Pass

So did I just pay $39 for a guy to say the light isn't on and looks good?

I know that I just needed 2 of the 3 (Cat, o2 & EVAP) test to be ready to pass & they just used a scanner in front of the building before pulling it in. I didn't see them actually put anything in the tailpipe to test the emissions but I was trying to not hover to closely. I think that might be correct unless they did that while a turned away.

 

[Brad J]

Low coolant temp readings can stall most the tests

That makes sense. I know the heater is working great now.