PO440 EVAP Control Sys Malfunction

PO172 Fuel Trim Bank 1 System too rich

It's an 03 with close to 44k miles, 4200 I6 motor. Need advise on what this is and what could of caused the problem, and need I be concerned or could it just have been a fluke???

Thanks in advance.

I would reset them and see if it happens again.

Seen the o2 sensors go bad on these and the furl tank filler neck on the tanks split apart. dont know why there is not a recall on that but have seen it many times.
you could have a lose fuel cap as well.

already reset the code to clear the service engine light and checked the fuel cap for looseness both seem good. Only thing I've done lately is I reset the change oil light last night which took several attempts(floormat). Anyhow I guess I'll wait a few days and see if it lights up again, if not a visit to Franklin and patrick may be in order

FWIW - just today the wifes '01 Yukon had the SES light go on. Read the code at Auto Zone P0442. In their little book of codes it was in the same group as the P0440 code you are throwing. I changed the PCV valve which fixed it. Cost me $2.37 :)

We do all diesel work but i can scan with the tech 2 and look it over. call us at
huckstorf diesel and talk to Mark he may let a fellow diesel place member slide a gasser in.

FWIW - just today the wifes '01 Yukon had the SES light go on. Read the code at Auto Zone P0442. In their little book of codes it was in the same group as the P0440 code you are throwing. I changed the PCV valve which fixed it. Cost me $2.37 :)If that works, your the first:confused:

If that works, your the first:confused:

I was surprised too! SES light came on and stayed on for two days and was on when the codes were read. It threw the P0442 code twice. Said it was a "small leak in the EVP system". Listed about 5 things to check: Vacuum leak at engine, faulty gas cap, cracked or leaking EVP canister and the last thing listed was something I don't recall what it was, but the initals of the 3 long words used were PVC (wasn't Positive Vent .....) :( So I took a shot and replaced the PVC (had 30K miles on the old one) in the parking lot, had them clear the code, restarted and havn''t had the SES come on again (its been about 40 miles now).

God knows- maybe he just gave me a break.

will be intersting to see, It has to fail two consecutive ign cycles to kick the light.

Keep us posted..

will be intersting to see, It has to fail two consecutive ign cycles to kick the light.

Keep us posted..

150 miles. several start cycles - still no SES light.

I reset the light and cleared the code and it hasn't returned as of yet. Not sure what it was, but I'm thinking wife and the gas cap.

Anyhow, I'm not so sure this 4.2 even has a PCV valve, if it does I've never been able to find it.

Service Engine Soon Light On, P0133, P0172 (Reprogram PCM) #04-06-04-053 - (Jul 20, 2004)

Service Engine Soon Light On, P0133, P0172 (Reprogram PCM)

2004 Buick Rainier

2003-2004 Chevrolet Trailblazer

2003-2004 GMC Envoy

2003-2004 Oldsmobile Bravada

with 4.2L Engine (VIN S - RPO LL8)

<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1538512&pubid=305&evc=sm#ss1-1538512">Condition

Some customers may comment on the Service Engine Soon light coming on and no apparent vehicle driveability condition.. Upon investigation, the technician will find diagnostic trouble codes P0133 or P0172.

<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1538512&pubid=305&evc=sm#ss2-1538512">Correction

Reprogram the PCM with the latest calibration available.

The new calibration will be released beginning with TIS satellite data update version 2.5 for 2004 available February 2004. As always, make sure your TECH2® is updated with the latest software version.

Warranty Information

For vehicles repaired under the applicable 8 year or 80,000 mile (130,000 kilometers) emission controller warranty, use:

<TABLE width="100%" border=1><TBODY><TR><TH vAlign=bottom align=middle>Labor Operation



</TH><TH vAlign=bottom align=middle>Description



</TH><TH vAlign=bottom align=middle>Labor Time



</TH></TR><TR><TD vAlign=center align=middle>J6353



</TD><TD vAlign=center align=middle>Module, Engine Control - Reprogram



</TD><TD vAlign=center align=middle>0.4 hr



</TD></TR></TBODY></TABLE>
(http://service.gm.com/servlets/BlobShtml?ShtmlFile=1538512&pubid=305&evc=sm#ss3-1538512)



On the p0440 code, we have done a lot of tank replacements on trailblazers. However, 440 can be set by a couple other things, really need to have that tested if you want to find the problem.

Many hundred miles and still no SES light - my case seems to be cured.