Three years running. when the gas tank sees about 60F, check engine light

[drvrd]

When weather gets cool enough ~60F going down my check engine light comes on, also goes off when temperatures are >60F. One can of STP water chase, STP injector cleaner or Techron makes the light go off until the next fill-up or two. She is a 2004 SLT Yukon and has 212K miles on her. A winter of STP water chase, STP injector cleaner or Techron per tank fill or two can get expensive.

Been told this is a fuel filter issue, does anybody concur? Any other suggestions?

Thanks in advance for your thoughts.

DrvrDon

 

[Fless]

Welcome to TYF.

I can't say if the problem is caused by a fuel filter issue, but if your truck is Flex Fuel there should be a fuel filter on the left frame rail. If it hasn't been changed lately, it would be a good idea to replace it.

When the check engine light comes on, what code is setting it? Bet it's an emissions code since the tank may be depressurizing when the fuel cools.

 

[wjburken]

Welcome to the forum from Iowa.

As mentioned already, figure out what code the vehicle is throwing next time the check engine light comes on. If you don’t have a reader, you local Autozone can get you the code for free. Just don’t blindly follow their scripted response as they want to sell parts and many don’t care if it actually solves the problem. That code is the first clue you need as it lets you know what the vehicle is erroring out on.

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics, please.

You have already received some initial feedback and suggestions, and other folks will chime in. As @wjburken stated, obtaining the code that is being thrown when the check engine light comes on will be the fastest and most accurate place to start in the diagnosis and resolution of this issue. We can provide more definitive assistance, once we know what code is being thrown.

 

[Doubeleive]

unless you are getting a mis-fire most check engine light causes are emissions related, fuel additives really shouldn't be fixing the issue and it may just be coincidence, if it is a code related to the fuel system like a vacuum leak, faulty solenoid, bad vapor canister, then the act of simply refueling and opening and closing the gas cap could be correcting the issue briefly.
We need that code to assist further, next time it comes on go get it scanned and report back.

 

[drvrd]

Thanks for everybody's comments.

The pattern I describe is very consistent for more than three running years, and persistent. I refueled half a tank refill yesterday while temperatures were in the Mid-60s. Had a check engine light from the half tank before adding half more refill when the check engine light went out afterward. PS same COSTCO fill source in all these cases. So no code possible until there is a temperature drop, unless the code detect has a history file capability. The station's in ground fuel tank has to be below 65F. Last year saw it come on immediately after refilling a low tank from a QT station.

I bought this 04 Yukon SLT used with 113K, and do not see indication of flex fuel capability (where can I check), but does have a fuel filter mounted on the frame rail about under the drivers seat.

Do the fuel cap seals have any history of age failure?

 

[Fless]

@drvrd Flex Fuel vehicles have a "Z" as the 8th VIN digit. What's yours?

And on a Flex truck there is a small E85 sticker inside the fuel door.

Unless it's been changed the fuel filler cap should be yellow. Any fuel cap can go bad; I've had to change mine due to it failing a seal test during an emissions inspection.

 

[Doubeleive]

Thanks for everybody's comments.

The pattern I describe is very consistent for more than three running years, and persistent. I refueled half a tank refill yesterday while temperatures were in the Mid-60s. Had a check engine light from the half tank before adding half more refill when the check engine light went out afterward. PS same COSTCO fill source in all these cases. So no code possible until there is a temperature drop, unless the code detect has a history file capability. The station's in ground fuel tank has to be below 65F. Last year saw it come on immediately after refilling a low tank from a QT station.

I bought this 04 Yukon SLT used with 113K, and do not see indication of flex fuel capability (where can I check), but does have a fuel filter mounted on the frame rail about under the drivers seat.

Do the fuel cap seals have any history of age failure?

yes check engine lights will stay as a history code, from what I have read some may go away after XX amount of restarts, others like abs or airbag may not stay as history codes.

 

[drvrd]

@drvrd Flex Fuel vehicles have a "Z" as the 8th VIN digit. What's yours?

And on a Flex truck there is a small E85 sticker inside the fuel door.

Unless it's been changed the fuel filler cap should be yellow. Any fuel cap can go bad; I've had to change mine due to it failing a seal test during an emissions inspection.

Yes 8th vin number is a Z, but fuel cap is black.

 

[Doubeleive]

ya there are some vin z that are not flex fuel I have one

 

[Fless]

There should be a small sticker inside the fuel door that indicates that E85 is allowed.

Since yours is a 2004 and is the L59 engine (based on the "Z" in the VIN) it's Flex, and the fuel cap doesn't HAVE to be yellow. Here's part of my '04's build sheet from GM:

 

[drvrd]

Yes 8th vin number is a Z, but fuel cap is black.

Ps Aurozone code reader only can read the current condition, and cannot read the history of prior codes.

 

[drvrd]

Really appreciate all the help I am getting. The Vehicle saw 42F so of course the check engine came back on. Fuel port door does show an E85 sticker.

PS vehicle came with a shift manipulation software change, OEM code readers cannot get past whatever this software changed. Autozone code reader ended with an error, and miss identified the vehicle as some 1215 chrysler and gave code report was bd2, as coil, sparkwiring and plugs. O'Reilly code reader did see it as GMC but did not not identify the vehicle model but produced a PO135 code(1/2) Stored, image below.

If O'Reily code is correct, clerk mentioned the O2 sensor can be cleaned. Is other then wire brushing needed?

 

[wjburken]

Really appreciate all the help I am getting. The Vehicle saw 42F so of course the check engine came back on. Fuel port door does show an E85 sticker.

PS vehicle came with a shift manipulation software change, OEM code readers cannot get past whatever this software changed. Autozone code reader ended with an error, and miss identified the vehicle as some 1215 chrysler and gave code report was bd2, as coil, sparkwiring and plugs. O'Reilly code reader did see it as GMC but did not not identify the vehicle model but produced a PO135 code(1/2) Stored, image below.

If O'Reily code is correct, clerk mentioned the O2 sensor can be cleaned. Is other then wire brushing needed?

View attachment 269095

I have never heard of anyone cleaning an O2 sensor. If you are going to go through the hassle of removing it from your exhaust pipe to try and clean it, replace it and be done with it.

 

[Fless]

Since the code points to the O2 heater, why not measure the resistance of the heater element in the sensor? Also, is the fuse for the heater good? Getting power all the way to the O2 connector?

 

[drvrd]

Since the code points to the O2 heater, why not measure the resistance of the heater element in the sensor? Also, is the fuse for the heater good? Getting power all the way to the O2 connector?

Burned 1/4 tank check engine light was on, warm engine but ambient air temp. About 55F, bought a STP water capture bottle and chk. eng light went out

 

[wjburken]

PS vehicle came with a shift manipulation software change,

Tell us more about this software change.

 

[drvrd]

Tell us more about this software change.

Code change was done before 2013. So it drove about 4 yrs without this check engine light issue. Will have to chase down the wand if this is important, or interesting otherwise

 

[wjburken]

Code change was done before 2013. So it drove about 4 yrs without this check engine light issue. Will have to chase down the wand if this is important, or interesting otherwise

I only ask as we don’t have an answer to your problem. How long did you own the vehicle before this particular temp related nuance rear it’s ugly head?

 

[drvrd]

I only ask as we don’t have an answer to your problem. How long did you own the vehicle before this particular temp related nuance rear it’s ugly head?

About four years.