Hi, new member here and 1st post. Recently purchased a 2006 LR3 V6 for my daughter and the check engine light only comes on after filling up until 3/4 of a tank then it goes off. Comes back on at around 1/4 of a tank. Local shop has checked the codes (something to do with left and right bank, I'll get the codes soon) and replaced a coolant sensor. After the work the check engine light came back on after refueling and still has the same issue........

Has anyone experienced this pattern before?

 

Odd one, There are a complicated set of hoses behind the gas fill. The most likely culprit seems like the gas cap. Otherwise maybe a split hose somewhere, possible even in the tank. You might want to bring it to the dealer to sort this one.

 

crossing my fingers however after dumping a 1/2 can of Seafoam in 1/2 tank of fuel and refueling twice, the check engine light has not come on........

 

That would have been my recommendation if you had not mentioned the fill up issues. -- as I recall, I had some sort of problem along these lines which turned out to be the tank seal... It gradually got worse, and I could smell gas a lot after a fill up... This is a major concern if you can smell gas after a fill up. Gas will leak out on to the exhaust, and you know what comes next...

 

alright, check engine light came back on (full tank), went and got a scanner and the codes are P0172 and P0175, any ideas.............

EDIT: Drove maybe 20 miles, made a few stops and of course the check engine light goes off.

 

P017200 -

* Restricted air filter
* High fuel pressure
* Leaking fuel injector(s)
* Oil contaminated with fuel
(too many cold starts with vehicle subsequently not
getting hot enough for long enough)
* MAF sensor fault
* Evaporative emission system fault

You should :

* Check the intake air system for restrictions, etc.
* Check the fuel system for leaks, DTCs, etc.
* Check the oil condition.
* Check for MAF sensor and evaporative emission DTCs.

Appears when all else seems normal (crate runs like a J79 in burner! and idles very smoothly), probably need to reprogram both the engine and tranny control module software

Check the o-ring on the MAF sensor...

I have have this fault turning up occasionally and am still working through it. My next steps are to replace MAF and up and down stream oxygen sensors. But my mechanic said to bring it and and he could pinpoint it by monitoring the data real time.. Have not gotten there yet.

 

thanks.......

 

just an update, problem seems to be fixed after taking it to the dealer. The aftermarket MAF sensor was bad, replaced with genuine OEM replacement and all is good. Why the check engine light came on after filling up and then goes off around 3/4 tank and then back on at a 1/4 still baffled everyone...........