Emissions Test Issue

[EddieC]

MikeZ71,
Holy cow!
So if someone took their car to a shop for a check engine light and the shop changed some parts related to the problem code and reset the light, would I be wrong in assuming that they just send the vehicle out "saying let's see how that goes" without that procedure?

 

[Fless]

The evap driving procedure is fairly standard, but most vehicles pass without having to do that all to a "t".

For the O2 issue, how many minutes does it take for the fuel system to go into closed loop? If the O2 heaters aren't working properly, you likely have bad fuel trims and a failed O2 activity and heater code.

 

[Doubeleive]

It's hardly possible to drive 55 on highways here without getting run over.
It showed three "not readys" ; Evaporative system, oxygen sensor and oxygen sensor heated.
The code reset was related to Evap system.

Deleted comment after reading other posts.

ya you could probably do 60 and be ok, it's legal so just pretend to be gramma
I had to do it before, I survived got it smogged and about an hour later the cel came on again lol

 

[EddieC]

The evap driving procedure is fairly standard, but most vehicles pass without having to do that all to a "t".

For the O2 issue, how many minutes does it take for the fuel system to go into closed loop? If the O2 heaters aren't working properly, you likely have bad fuel trims and a failed O2 activity and heater code.

I don't believe the readout on the error code, P0449, (prior to the emission test) mentioned O2 sensors. It mentioned vent solenoid control circuit.
From reading that a code reset erases other data, I am assuming that the emission test "not ready" report on the O2 sensors could be related to the reset.

 

[EddieC]

MikeZ71,
On a quick peek on the status today I did see some "No"s listed but didn't write them down.

On the procedure that you posted, does that have to be done from a clean reset or do it anytime after some driving?

Also in the linked article it mentions "EVAP Service bay test".
Can you shed light on that?

 

[mikez71]

To me, it sounds like you need to fix the P0449 code.
Sorry I don't know anything about that procedure, I just copy/pasted it from the Range disabler website.
BUT I would assume you can do it anytime.

First time I read your posts I saw you mention P0449 came back awhile after replacing purge valve.
Second time I missed that and thought it was in my head..
Third time I read it again and found where you mentioned it!

So it sounds like you could have a new bad valve..
Or maybe it wasn't an issue with the valve, but one with the hose or canister..

Personally, I would replace the canister anyways because I see so many posts about that..
And while you're in there check the hoses and valve if possible .
Purge valve should be closed when unpowered?
And I don't know how you would check the hose without removing it...Might have to pressurize or vacuum test the fuel tank w/hose?

 

[EddieC]

To me, it sounds like you need to fix the P0449 code.
Sorry I don't know anything about that procedure, I just copy/pasted it from the Range disabler website.
BUT I would assume you can do it anytime.

First time I read your posts I saw you mention P0449 came back awhile after replacing purge valve.
Second time I missed that and thought it was in my head..
Third time I read it again and found where you mentioned it!

So it sounds like you could have a new bad valve..
Or maybe it wasn't an issue with the valve, but one with the hose or canister..

Personally, I would replace the canister anyways because I see so many posts about that..
And while you're in there check the hoses and valve if possible .
Purge valve should be closed when unpowered?
And I don't know how you would check the hose without removing it...Might have to pressurize or vacuum test the fuel tank w/hose?

It threw the original P0449 code on a previous valve (if that's the one atop the engine) and three weeks later on the replacement.
I guess it took three weeks for the system to come back to ready.
So perhaps it might be something in the canister end of the system.

 

[Fless]

It threw the original P0449 code on a previous valve (if that's the one atop the engine) and three weeks later on the replacement.
I guess it took three weeks for the system to come back to ready.
So perhaps it might be something in the canister end of the system.

P0449 has to do with the VENT valve circuit, not the purge valve on the engine. The vent valve (technically a solenoid, as is the purge valve unit) is located in the rear of the truck, near the spare tire. It vents the canister at certain times; the canister stores fuel vapors and vents "clean" air through the vent valve.

Most times that code is caused by a faulty vent valve, but not always. The solenoid might click but the valve that the solenoid controls might stay open or closed, instead of being actuated by the solenoid. It could be defective mechanically (solenoid or valve stuck) or electrically (solenoid not responding to open/close commands).

Easy enough to test; do you need references to test procedures? Here's one that show an electrical test; it's not your vehicle but the test would still be similar on yours. You don't need a Power Probe, just a 12vDC source to see if it clicks.

If I were you I'd just replace the vent valve with a quality new one. You can always test the old one on the bench.

 

[j91z28d1]

"Not ready" was reported as a failure and 90 days to retest. I don't know what happens if it's not ready again.

interesting.. what state do you live in. I wish er could sort out the specs for each state. I sware someone just passed theirs with the evap not ready before everyone else passed.


was yours just evap not ready. or others on the list not ready too.

 

[EddieC]

P0449 has to do with the VENT valve circuit, not the purge valve on the engine. The vent valve (technically a solenoid, as is the purge valve unit) is located in the rear of the truck, near the spare tire. It vents the canister at certain times; the canister stores fuel vapors and vents "clean" air through the vent valve.

Most times that code is caused by a faulty vent valve, but not always. The solenoid might click but the valve that the solenoid controls might stay open or closed, instead of being actuated by the solenoid. It could be defective mechanically (solenoid or valve stuck) or electrically (solenoid not responding to open/close commands).

Easy enough to test; do you need references to test procedures? Here's one that show an electrical test; it's not your vehicle but the test would still be similar on yours. You don't need a Power Probe, just a 12vDC source to see if it clicks.

If I were you I'd just replace the vent valve with a quality new one. You can always test the old one on the bench.

I have on oem on order. I can't afford therapy.
Good video.

 

[EddieC]

interesting.. what state do you live in. I wish er could sort out the specs for each state. I sware someone just passed theirs with the evap not ready before everyone else passed.


was yours just evap not ready. or others on the list not ready too.

There were three "not readys", probably because I had done CEL reset a few days before only for a P0449 code. I didn't realize that the action would erase other stored data but the CEL alone would be a test failure.
The three things not ready were Oxygen sensor, Heated Oxygen sensor and the EVAP system.

 

[Fless]

Check your I/M monitors with your scanner to see if the O2 codes passed by now, and that the evap is the only issue.

 

[Doubeleive]

MikeZ71,
On a quick peek on the status today I did see some "No"s listed but didn't write them down.

On the procedure that you posted, does that have to be done from a clean reset or do it anytime after some driving?

Also in the linked article it mentions "EVAP Service bay test".
Can you shed light on that?

A evap test can be done with a tech2 under certain circumstances, like it has to be cold, then the test has to be ran with rpm's held between 2~4k rpm or something like that and if you accidentally bump it up or down you have to start over and then it's no longer "cold" so ya major pita.

 

[j91z28d1]

There were three "not readys", probably because I had done CEL reset a few days before only for a P0449 code. I didn't realize that the action would erase other stored data but the CEL alone would be a test failure.
The three things not ready were Oxygen sensor, Heated Oxygen sensor and the EVAP system.

ahh that makes sense, yeah you gotta catch with when it's the only one that says. unavailable but everything else has passed but not long enough it sets the check engine light.

 

[Fless]

If you're interested Mike at Go Tech (Wells) does a great job of explaining evap systems and tests. Some are specific to GM systems.

GoTech

Automotive repair content hosted by ASE Master Certified technicians with a focus on diagnosing and repairing today's problem vehicles with speed and accuracy.

www.youtube.com

 

[EddieC]

ahh that makes sense, yeah you gotta catch with when it's the only one that says. unavailable but everything else has passed but not long enough it sets the check engine light.

Today the only one still noted as "INC" was the obed system so some progress is made.
Waiting on the valve delivery.

 

[EddieC]

Put the new valve on today after having to scramble around town to find an adapter wiring pigtail.
Thanks GM for changing the wire plug socket shape in the oem valves that you manufacture now and not include the wire or even a warning!
The aftermarket valves seen for sale include the adapter wire but GM does not.
NAPA had it but charges five times mail order price.

 

[EddieC]

Ok, after a hundred miles down the highway at 55 mph today the computer came completely back to ready state and passed the emissions retest.

There was still a downside to passing the retest as the state cut the next test schedule spacing in half so one year instead of the standard two years. I called the state on it and was told it was because there was a failure and weren't sympathetic to fact that there was an actual failure in the previous test but rather there were "not ready" reports. Seems they really want that $20 to recoup for the free retest today.

Anyways, thanks for the advice.

The lesson learned is that erasing a CEL code wipes out other historical recorded data on the vehicle.

 

[89Suburban]

No good sumsabtches so sick of this game while everyone elses drives around in whatever shit box they please fkn joke

 

[EddieC]

No good sumsabtches so sick of this game while everyone elses drives around in whatever shit box they please fkn joke

I missed my test (by not knowing when it was due) some years ago and after paying the late fee (that bill came in a flash) I asked when I have to get the test now that I paid up; I was told don't worry about it.
Draw one's own conclusion.