XJ Failed Emissions Test

2001 XJ (58,000 miles) failed and has codes P0442 (small leak) and
P0455 (large leak) in the evaporative emissions system. Other than the
gas cap, does anyone have any ideas what to look for first? Thanks.

P0442 OBD-II Trouble Code
Technical Description
Evaporative Emission Control System Leak Detected (small leak)
What does that mean?
This indicates a fuel vapor leak in the EVAP control system. It means a very
small leak has been detected. In fact, the leak can be from a hole as small
as 0.04" in diameter. The (EVAP) emission control system prevents the escape
of fuel vapors from a vehicle's fuel system. Fuel vapors are routed by hoses
to a charcoal canister for storage. Later, when the engine is running a
purge control valve opens allowing intake vacuum to siphon the fuel vapors
into the engine.
Symptoms
You likely won't notice any drivability problems.
Causes
A code P0442 most likely means one or more of the following has happened:
.. A loose or improperly affixed gas cap
.. A non-conforming gas cap (i.e. not factory/original brand)
.. A small leak/hole in a fuel vapor hose/tube
.. Other small leak in EVAP system
.. Faulty vent o-ring seal
Possible Solutions
With a P0442, the most common repair is to:
.. Remove and reinstall the gas cap, clear the codes, and drive for a day and
see if the codes come back.
.. Otherwise, replace the gas cap, or
.. Inspect the EVAP system for cuts/holes in tubes/hoses


P0455 OBD-II Trouble Code
Technical Description
Evaporative Emission Control System Leak Detected (no purge flow or large
leak)
What does that mean?
This indicates a fuel vapor leak or lack of purge flow in the EVAP control
system. It means a large leak has been detected. The (EVAP) emission control
system prevents the escape of fuel vapors from a vehicle's fuel system. Fuel
vapors are routed by hoses to a charcoal canister for storage. Later, when
the engine is running a purge control valve opens allowing intake vacuum to
siphon the fuel vapors into the engine.
Symptoms
You likely won't notice any drivability problems.
Causes
A code p0455 most likely means one or more of the following has happened:
.. A loose or improperly affixed gas cap
.. A non-conforming gas cap (i.e. not factory/original brand)
.. Other leak or damaged piece in EVAP system
Possible Solutions
With a p0455, the most common repair is to:
.. Remove and reinstall the gas cap, clear the codes, and drive for a day and
see if the codes come back.
.. Otherwise, replace the gas cap, and/or
.. Inspect the EVAP system for cuts/holes in tubes/hoses (you may hear a
vacuum noise or smell fuel), repair if necessary



"kokonutty" > wrote in message
oups.com...
> 2001 XJ (58,000 miles) failed and has codes P0442 (small leak) and
> P0455 (large leak) in the evaporative emissions system. Other than the
> gas cap, does anyone have any ideas what to look for first? Thanks.
>

http://www.wjjeeps.com/faultcodes.htm
God Bless America, Bill O|||||||O
http://www.billhughes.com/

kokonutty wrote:
>
> 2001 XJ (58,000 miles) failed and has codes P0442 (small leak) and
> P0455 (large leak) in the evaporative emissions system. Other than the
> gas cap, does anyone have any ideas what to look for first? Thanks.

Thanks for the fast replies guys...pretty much what I thought, but I
was hoping someone might point me beyond the gas cap to where they may
have seen specific problems in the past. The info BH III posted
including the TSB is for Grands, not XJ's but DCP valve could be the
source, I guess but it doesn't seem easy to get at right away on the
Grand and no idea wher it is on the XJ.

It's the gas cap. Period! You will find a little condensation rust
stain around the center vent hole. Replace it.
And the code would have been the same on a PT Cruiser:
http://www.ptcruizer.com/computer-codes.html
God Bless America, Bill O|||||||O
http://www.billhughes.com/

kokonutty wrote:
>
> Thanks for the fast replies guys...pretty much what I thought, but I
> was hoping someone might point me beyond the gas cap to where they may
> have seen specific problems in the past. The info BH III posted
> including the TSB is for Grands, not XJ's but DCP valve could be the
> source, I guess but it doesn't seem easy to get at right away on the
> Grand and no idea wher it is on the XJ.

kokonutty wrote:
> Thanks for the fast replies guys...pretty much what I thought, but I
> was hoping someone might point me beyond the gas cap to where they may
> have seen specific problems in the past. The info BH III posted
> including the TSB is for Grands, not XJ's but DCP valve could be the
> source, I guess but it doesn't seem easy to get at right away on the
> Grand and no idea wher it is on the XJ.
>
If it turns out not to be the gas cap my "P0442" was a minute crack in a
hose. Couldn't find it. The dealer (mine at least) has a smoke generator
that will spot the leak.

--
FRH

When I had the P0456 error code this was the cause:

http://www.imagestation.com/album/?id=2122725727



"L.W.(Bill) Hughes III" > wrote in message
...
> It's the gas cap. Period! You will find a little condensation rust
> stain around the center vent hole. Replace it.
> And the code would have been the same on a PT Cruiser:
> http://www.ptcruizer.com/computer-codes.html
> God Bless America, Bill O|||||||O
> http://www.billhughes.com/
>
> kokonutty wrote:
>>
>> Thanks for the fast replies guys...pretty much what I thought, but I
>> was hoping someone might point me beyond the gas cap to where they may
>> have seen specific problems in the past. The info BH III posted
>> including the TSB is for Grands, not XJ's but DCP valve could be the
>> source, I guess but it doesn't seem easy to get at right away on the
>> Grand and no idea wher it is on the XJ.

You can clean it?
God Bless America, Bill O|||||||O
http://www.billhughes.com/

billy ray wrote:
>
> When I had the P0456 error code this was the cause:
>
> http://www.imagestation.com/album/?id=2122725727

The gas cap is by far the most likely cause of your problems. By far.

They can test the cap to see if it holds pressure, I don't get why this
would cause a failure at the smog station. If the cap is bad, they are happy
to sell you a new one for more than double the "street price" and reset the
code and move on.





"kokonutty" > wrote in message
oups.com...
> 2001 XJ (58,000 miles) failed and has codes P0442 (small leak) and
> P0455 (large leak) in the evaporative emissions system. Other than the
> gas cap, does anyone have any ideas what to look for first? Thanks.
>

Have you ELIMINATED the gas cap yet?

The gas cap is common to both codes, and is by a wide margin the most likely
source of the codes you got. You MUST eliminate the gas cap as the source
before you go any deeper, or you will be wasting both time and money. If you
went out and bought a locking gas cap to keep ****heads from stealing your
gas, then the cap is the cuplrit. I've been told by at least two smog
testers that locking gas caps frequently fail the pressure test that they
put the caps through.





"kokonutty" > wrote in message
oups.com...
> Thanks for the fast replies guys...pretty much what I thought, but I
> was hoping someone might point me beyond the gas cap to where they may
> have seen specific problems in the past. The info BH III posted
> including the TSB is for Grands, not XJ's but DCP valve could be the
> source, I guess but it doesn't seem easy to get at right away on the
> Grand and no idea wher it is on the XJ.
>