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p0455 how long until I know it's fixed?

outracing

NAXJA Forum User
Location
ohio
Hi everyone. I have a 1999 x's that is giving me the "large leak EVAP" code. I replaced the LDP, gas cap, and found and replaced a cracked steel line. I have smoke tested it and found that my valve cover gasket and oil filler cap had leaks. I was able to tighten the valve cover to correct that and replaced the oil filler cap. I now get no smoke from anywhere in the system when smoke testing. My CEL seams to be staying on. How long until I can no for sure I am fixed? I don't really want to disconnect the battery and wait and see if the light comes back, rather see it shut off when the problem is fixed.
 
Are you using a scanner?? Your own? Or are you having the code read at a shop?

I don't know about the Jeep specifically as I don't have OBD (I or II) on my Renix's I can only offer my exp. with my Nissan. Have you cleared the code with your scanner? The light may have to be cleared and then driven 50 miles or so to see if it comes on... it may not just go off on it's own.

OR...if you turn the light off (clear the code) and then check it again after the first couple of drive cycles, then check with your scanner for "pending codes".

It's interesting that your valve cover was loose enough to allow smoke out...do you have a massive oil leak.
 
A valve cover leak will not set an evap code. Your evap system will set the code, you need to smoke the evap line to the gas tank and see if maybe the purge valve is leaking, Generally a large leak is a busted line or a gas cap without a seal
 
Are you using a scanner?? Your own? Or are you having the code read at a shop?

I don't know about the Jeep specifically as I don't have OBD (I or II) on my Renix's I can only offer my exp. with my Nissan. Have you cleared the code with your scanner? The light may have to be cleared and then driven 50 miles or so to see if it comes on... it may not just go off on it's own.

OR...if you turn the light off (clear the code) and then check it again after the first couple of drive cycles, then check with your scanner for "pending codes".

It's interesting that your valve cover was loose enough to allow smoke out...do you have a massive oil leak.

A valve cover leak will not set an evap code. Your evap system will set the code, you need to smoke the evap line to the gas tank and see if maybe the purge valve is leaking, Generally a large leak is a busted line or a gas cap without a seal

I know that a VC leak would not set a code...I was just surprised that the smoke would come out of the VC cover and wouldn't be spewing oil...just a side comment, not a solution to the code. Sorry.

Still, the OP needs to clear the code as not all OBD systems turn the light off after the problem is fixed.
 
The short answer is 3 good trips.. here is the long answer...

The term “Trip” has different meanings depending on what the circumstances are. If the MIL (Malfunction Indicator Lamp) is OFF, a Trip is defined as when the Oxygen Sensor Monitor and the Catalyst Monitor have been completed in the same drive cycle.
When any Emission DTC is set, the MIL on the dash is turned ON. When the MIL is ON, it takes 3 good trips to turn the MIL OFF. In this case, it depends on what type of DTC is set to know what a “Trip” is. For the Fuel Monitor or Mis-Fire Monitor (continuous monitor), the vehicle must be operated in the “Similar Condition Window” for a specified amount of time to be considered a Good Trip. If a Non-Contiuous OBDII Monitor fails twice in a row and turns ON the MIL, re-running that monitor which previously failed, on the next start-up and passing the monitor, is considered to be a Good Trip. These will include the following:
Oxygen Sensor
Catalyst Monitor
Purge Flow Monitor
Leak Detection Pump Monitor (if equipped)
EGR Monitor (if equipped)
Oxygen Sensor Heater Monitor
If any other Emission DTC is set (not an OBDII Monitor), a Good Trip is considered to be when the Oxygen Sensor Monitor and Catalyst Monitor have been completed; or 2 Minutes of engine run time if the Oxygen Sensor Monitor or Catalyst Monitor have been stopped from running. It can take up to 2 Failures in a row to turn on the MIL. After the MIL is ON, it takes 3 Good Trips to turn the MIL OFF. After the MIL is OFF, the PCM will self-erase the DTC after 40 Warm-up cycles. A Warm-up cycle is counted when the ECT (Engine Coolant Temperature Sensor) has crossed 160°F and has risen by at least 40°F since the engine has been started.




 
Wow, thanks everyone for all the responses, I am going to clear the code by disconnecting my battery right now. I wish there was a way to know if this code is cleared for good or if the problem still exists. My valve cover does (did?) leak oil, but not a lot. In fact, I never noticed it until I did this smoke test. I have been using a home made unit, and testing at the diagnostic port next to the purge valve, some people have told me that there is more to just putting smoke in the lines, that I have to "seal" the system. So now I am unsure if I have done good tests. Let's just hope that all the items that I replaced did the trick and the light stays off.
 
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