Vacuum Leak/Check Engine light

[JJ_SC]

Hey guys,

I've had my check engine light come on for the third time now. The code is a slight or minor vacuum leak. Can't remember the exact wording. First time it appeared my mechanic just cleared it for me as I was on my way outa town. Second time I guess they did a smoke test and found it pouring out of the gas cap. So, I replace the gas cap. That didn't solve it. The ligth is back on. It seems to get triggered on cold mornings.

So I'm wondering if there are any known places to look for on these trucks. Any obvious points that people know about? I did a search but didn't turn up anything.

It must be a minor leak as I can't detect any change in the performance of the engine. Still idles smoothly. Makes me wonder if the idiot light is the idiot!

Thanks!
JJ

 

[Trunk Monkey]

Can you get the actual code #?

 

[JJ_SC]

Yeah, I'll take it by tomorrow and have it scanned. Can't remember it off hand. I'll get more info...

JJ

 

[NMuzj100]

I like shooting in the dark so ...

I'm guessing charcoal canister valve.

 

[JJ_SC]

Got the code from the shop today: P0456 - emissions control, very small leak.

Did a search of the internets and turned up somebody else that had a problem with the charcoal canister valve. Maybe that's it??? Just wondering if there's a common failure that I should test/try first.

Thanks!

JJ

 

[RumBum]

Got the code from the shop today: P0456 - emissions control, very small leak.

I just got the P0456 code on my '06 LX. What was the fix with yours? Canister valve or new gas cap? Hoping it's something cheap and easy.

 

[LCHardriver_02]

As per the original post: "So, I replace the gas cap. That didn't solve it."

 

[RumBum]

As per the original post: "So, I replace the gas cap. That didn't solve it."

Awesome, thanks! Now I know it wasn't the gas cap, but still don't have an answer to what fixed the problem.

 

[LCHardriver_02]

Oops sorry. Got confused.

 

[Kigiin]

I like shooting in the dark so ...

I'm guessing charcoal canister valve.

I had the same and my problem was the canister - found a used one on ebay for $200, but haven't cleared to code yet so don't know for sure if that solves it. However, the smoke test revealed the canister was leaking pretty good.

I haven't cleared the code yet because so low life stole my Ultra Gauge the second day I had it. Didn't even have time to hook it up.

 

[RumBum]

Stopped by the Lexus dealer today to have my P0456 looked at. A complimentary tuna sandwich and 45 minutes later, they let me know it was a bad gas cap. They ran the test on the emmission system and the charcoal canister and hoses were fine. $32 fix and pretty happy about that. Hopefully I don't run into the problems listed above in a few hundred miles. I really don't want to get into replacing the charcoal cannister, etc.

 

[TwiceWithHair]

P0456 joining the club!



My gas cap seems fine. I'm gonna clear the code and hope this was a fluke from last fill up. Were others' gas caps obviously faulty?

 

[AppleTech]

So I'm having this come up now - going to check the gas cap but what is the "smoke test" and how does one perform it to test for vacuum leaks?

 

[2001LC]

Interesting bad fuel pump issue in the 06's being reported in https://forum.ih8mud.com/threads/really-strong-exhaust-fumes-on-my-100.909563/page-2 which may not be related, but worth mentioning.