TCP64

I went over a tall speed bump in a trailer park today (didn't see it) and immediately afterwards I got a CEL light. When I got home I hooked up my OBDLink and retrieved 2 codes: P0442 and P0445. I searched the 2 Jeep sites I'm a member of and found that they are related to the emissions vacuum system. I inspected all the vacuum lines I could get to and checked the gas cap, but couldn't find any obvious issues. I cleared the code and if it comes back I'll dig into it further. I did notice that the vapor canister purge solenoid was not clicking, which according to what forum members say, should be. Does anyone else's click?

Noah911

I am nowhere near either of my Jeeps to
check and listen closely. I do know that on my ZJ it clicks rather loudly. With the hood open it is very noticeable. I did a lot of work on the ZJ recently.. So, I kind of remember it pretty well. It seems to me that I remember it does not click much if at all upon a cold start-up, but it would click very regularly when the engine was fully warmed up. I did not really notice if the clicking speed ever would dissapear, or if it was at a variable rate though?

On my WJ the clicking is much more subdued. Almost to the point where it is not even noticeable. It's way quieter than how the ZJ clicks I know that much.

Does it click on cold start-up? From what I read in the FSM it is controlled by the PCM being energized/de-energized to cycle... It's supposed to be de-energized while in open loop. Then, the PCM cycles it on/off after entering into closed loop as the engine gets hot. So, I gather it is not supposed to always click.. Specifically, it is not supposed to be going through the energized/de-energized cycle to click any upon a cold start-up. There is a warm/hot-start delay set to a timeframe too. So, it should not begin clicking immediately right away when you start the engine if it is a hot engine temperature even though it may basically be started in the closed loop.

From what I read the clicking is not an issue to worry about.. Unless, you get those codes. The CELs you were seeing.. That would make me wonder about the system. If you re-set the codes and they went away as you did.. If there is an issue, those codes would probably return within 100 miles.

If the codes do return.. I would begin investigating for the potential reasons. From what I understand, it may be related to a lot of different things. Some that I saw were possibly a faulty gas cap, a leak in the fuel tank filler neck, or a leak in a certain line that comes up off the gas tank itself. Do you smell gasoline? I guess it could also be certain vacuum lines that may be leaking as well. I'm not sure which ones are the ussual culprit lines? Except to say if the codes return, it could possibly be any of the soft or rubber/plastic vacuum lines.

I guess a smoke test and a fuel lines/system test would probably be the way to go when digging further into any investigations if those codes do come back on you.

(edited to add):
I asked above if you could hear it clicking on a cold start-up. What I was meaning to relay and get across was more along the lines of questions asking; how you discerned to notice yours does not click any at all? Pretty much.. I was asking if you listened for the clicking for a short time only after a cold start-up? Or, if you were listening for the click only for a short time immediately after a warm start-up.. because, if you did not listen for a long enough timeframe to let the warm start delay time itself out, then it would be normal not to hear any clicking... Or, if you listened for the clicking after the Jeep had been on and running for awhile.. some time well after the Jeep had been started? It should be noticeably clicking at this point if the Jeep was on and running for awhile when you were listening.

I do not know what it would mean if it never does click any at all? From how I understand it.. I think it could mean you may have a fualty solenoid? Or, it sounds like it may possibly mean there is a fault within the portion of the PCM responsible for causing the energization and de-energization action cycle to occur for at the solenoid? This is probably a much less likely reason in my mind though.. to have that type of a fault in the PCM.

TCP64

Well, after clearing the CEL's awhile back I've probably put about 70 miles on it without the CEL coming back. I suspect that the speed bump jarred something just enough to throw the code.