![]() 04/22/2015 at 10:04 • Filed to: None | ![]() | ![]() |
So, My GF’s 2003 Tacoma SR-5 4x4 extra-cab (3.4l V6, auto) has been throwing code P0456 “Evaporative emissions leak detected (very small leak)“. None of the mechanics that have looked at it have been able to find the leak and they’ve all just shrugged, reset the MIL and moved on. This includes the Toyota dealer. Last autumn they replaced her rusty frame under the terms of her extended warranty and tried to track it down then too. The best they could come up with is “we can try replacing your fuel tank ($800) and see if it goes away...” or “we can just reset the light again...”
It goes away in cold weather, and never throws the code as long as the ambient temperature stays below about 40 degrees F. Now that spring is here, so is the code. It comes back within 2 or 3 drive cycles, and near as we can tell doesn’t care how full the gas tank is.
The gas cap, filler tube and purge valve have been replaced. Any “classic” places this could be coming from or are we just destined to keep resetting the light until the leak gets big enough to detect with a sniffer?
![]() 04/22/2015 at 10:06 |
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I dont have a taco. But I have driven with a small evap leak for the last 20,000 kms or so with no ill effects. It’s annoying, but you gotta do what you gotta do, my cavalier has the exact same problem. If you need to take through emissions let me know I will tell you how even if they use a OBD 2 reader thing for it.
![]() 04/22/2015 at 10:09 |
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Does it have a charcoal canister? If so, have you checked the bung gasket on the vacuum flange?
![]() 04/22/2015 at 10:17 |
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a quick Google indicates it does indeed have a (very expensive and complex) cannister, and an indication that the vent control valves sometimes fail... I’ll have to have a look at that.
![]() 04/22/2015 at 10:23 |
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I can almost guarantee it’s made out of ABS and has a rubber gasket. Take that, couple it with the fumes from 12 years of operation, and you get very brittle plastic and a shot gasket.