I have an 07 Ls 2.2. 168,00 miles. Rode hard and put away wet. NO CODE IF GAS CAP IS OFF.
Symptoms are ....runs hot around town. reduced fuel consumption. slight reduction in power. When I noticed these performance issues I hooked up my innova 3100 scan tool. No codes or engine light were coming on, but scan tool showed a blinking evap icon when all other icons were solid. Also red/yellow/ green emmissions light was on yellow. Only other symptoms that IF I LEAVE MY GAS CAP OFF and drive many miles, no code is thrown.
doesnt seem to be any pressure in tank when removing gas cap. I started at the back (new gas cap) and found the vent solenoid was clogged with a fine silt, about 1/3 of a cup. Many dusty roads. No bueno. Vent tube to outside air on 07 is straight up in the wheel well. SO i put a goose neck on it like later models have. Installed new vent sol. If I disconnect any hoses/connectors on the evap systemit will throw the appropriate codes. NO CHANGE. New cannister,purge solenoid. NO CHANGE. Took it to the dealer for diagnosis w/ their scan equip. Evap system fine. The only thing they found was no ground on low speed engine cooling fan circuit at ecm.????? Did NOT install new ecm as I figured there is more. STILL NO CHANGE,NO CODES. Fan comes on at 217 or with a/c as is normal. Is there 2 SPEEDS? to my cooling fan? I was not aware and I have had my head in that engine compartment alot replacing crappy gm original stuff. Why no gas cap, no code?

 

Hmmm, 168k on the clock leads me to a few questions.

1. When was the cooling system serviced, and are you still running with the original thermostat?

2. When were the plugs changed, they need to go at 100k and be replaced with the proper Delco 41-103 Iridium plugs.

3. Running around without a fuel cap should throw a code, very odd behavior there.

4. Is it regularly hitting 217 degrees in traffic, that's higher than I'd be comfortable with.

5. When was the engine air filter last changed, has the throttle body been cleaned along with the MAF sensor?

6. What were/are the exact codes its throwing?

I revised your thread title, ones that start with just one word, or a lack of description can(and do)get overlooked here.

 

Oh, and paragraphs can be helpful to us geezers with bifocals.

Mine routinely hits 217.

Could be that the EVAP test has not run yet. It is touchy to get to run and takes a long time, mine took 2000 miles. There will be no codes, just not ready warning on the OBDII. The test will not run if any component is not working (gas cap off). The way it works when it does is to pump up the pressure in the tank.

Disconnecting the battery or resetting codes will put all of the emissions test into "not ready" mode until they run next. Some run right away, some require the "stand on one foot while waving the opposing hand in a clockwise direction and waving the other hand in a counter-clockwise direction while drinking a hot cup of coffee upside down" procedure.

 

Thank all of you for your input. In regards to service... K&n filter cleaned regularly, new coolant, new t stat. new radiator (old one took a rock and it sprung a leak), hoses, map cleaned, throdle body cleaned, plugs changed, fuel injector cleaner added to tank. A funny thing happened. Got home, Plugged in scanner, and evap icon doesnt blink any more, green emissions light is on, and I noticed a return to normal gpm. I think it took 2000 miles for it to return to normal (at 200 miles per day). I hope it takes. Still runs hotter in town than it should be ( but this is my first vehicle with an electric fan only, no engine driven fan). Is there 2 speeds to the fan, or a lower start temp for city driving (because of air flow)? Dealer says "tested high speed fan circuit from ecm to fuse block and found circuit to be good. Tested ecm ground circuit and determined failure to be at engine control module". The fan comes on @ 217 or with a/c as is normal ,but freeway is 189 and stop and go varies from 189 to 210 in 30 seconds. I promise I will figure out the paragraph thing.
typing is not my best feature.

 

Your temps are exactly like my 2011 2.2L. The EVAP test finally ran, just like mine. Never heard of 2 speed fan.

The lesson I have been trying to get out there is : error codes don't always mean what they say. For instance mine said catalytic converter failure, a new exhaust gasket and a Seafoam treatment fixed it.

I drive a minimum 200 miles a day if I don't make any money.

 

I drove again today and its like someone flipped a switch. Mileage great ( avg 29). I think I have been impatient on the cycles for clearing evap.

I filled up the tank this morning and the estimated miles was 510. I have never, ever seen that high before. The exhaust manifold had a crack so that was replaced. Shortly thereafter the cat conv. took a dump. Shes running clean now but I still feel that temp is higher than I remember. Thats what took out the manifold.

I also hoped that the gas cap issue was resolved, but no luck. I can still run down the road and no code will be thrown. ???

One other item that I just noticed this morning was the outside air temp digital readout was stuck on 66 degrees for half the day (morning temp). When it did change It went straight to 86 which was correct for 6 hours later (in the afternoon). It always seemed to be accurate in the past. Where is the outside air temp sensor ???

 

Not exactly sure on your model, but on my SS they hid it pretty well.
- In the yellow circle, under the red flap-

Attachment 15380

 

I just love it when extra information is supplied after the fact. Little things like new exhaust manifold a new cat.

The gas cap code does not come on immediately, it can take quite a few miles. That is not a good test for anything, don't worry about it. What you care about is all green on the emissions module of your OBDII reader.

 

Thanks for all the help. After fuel injector cleaner added to tank helped alot, I decided a proper injector cleaning would not be a bad idea. The cost of a cleaning was just a little less than me installing new ones, so thats what I did
and everything is fine now.

Still no code shows with gas cap off, but I have decided to ignore it.

 

It can take a long time to get the EVAP test to run, until it does you won't get a code. Don't drive around with the gas cap off.