Hole above gas cap (P0456)

[DOwen33]

Hello, recently picked up my ‘06 LX470 and she started throwing P0456 (Evaporative Emissions Control System Leak Detected (Very Small Leak)) a couple weeks ago. CEL comes on with VSC TRAC and VSC OFF lights as well. Cleared the codes with Techstream and the lights came back a week later, so I ordered a new OEM gas cap. As I was installing it I noticed a small hole in the rubber boot surrounding where the gas cap threads on, pictured above. Anyone know if this is designed this way or damaged? Could it be causing the emissions leak?

 

[seanz0rz]

The boot is just a seal for the body, not part of the fuel/emissions system.

Look for splits in the hoses that are above the spare tire. That's where mine was.

 

[DOwen33]

The boot is just a seal for the body, not part of the fuel/emissions system.

Look for splits in the hoses that are above the spare tire. That's where mine was.

Got it, thanks.

 

[DOwen33]

The boot is just a seal for the body, not part of the fuel/emissions system.

Look for splits in the hoses that are above the spare tire. That's where mine was.

Another question since it sounds like you’ve dealt with this code before. After the leak is fixed, how long does it take for the CEL to go off? Does the vehicle run an evap emissions leak test once a week, and that’s why it took a week for my CEL to come back on after I cleared it the first time?

 

[ceylonfj40nut]

Three clicks when you put the new cap on. My son was chasing the same issue for months. Was not doing three clicks. New gas cap is the way to go. To tithe us, we used a slight smear of grease on the gasket, it was not cracked but stiff.

 

[seanz0rz]

Another question since it sounds like you’ve dealt with this code before. After the leak is fixed, how long does it take for the CEL to go off? Does the vehicle run an evap emissions leak test once a week, and that’s why it took a week for my CEL to come back on after I cleared it the first time?

Yes the EVAP is not checked but periodically (a week sounds about right, I can't recall the exact frequency or conditions it is run.

My split was on the top of a hose, you couldn't see it from underneath. I found it with my fingers after pulling my hair out looking for the leak. Even a shop couldn't find it, but isolated it to the canister and connections.

 

[DOwen33]

Three clicks when you put the new cap on. My son was chasing the same issue for months. Was not doing three clicks. New gas cap is the way to go. To tithe us, we used a slight smear of grease on the gasket, it was not cracked but stiff.

Sweet, love hearing evap leak success stories. Saw another thread where this was their solution. I’ll give it a try.

 

[Trunk Monkey]

Get yourself a cheap Bluetooth code reader and you can clear the code from it. The system isn't run weekly, it requires a set number of criteria to be met to throw the code - number of drive cycles, type of driving, code pending, etc.