Chrysler Repair Questions? Ask a Mechanic for Answers ASAP
You have a mixture of evaporative system leak, purge performance and general evap system failure codes... the sum of which often means you have a bad NVLD or an extremely large evaporative system leak. Hi, my name isXXXXX to Just Answer!.
NVLD stands for natural vacuum leak detector, which is actually the evaporative system cop. Its job is to partly seal the evap system during testing to allow a slight vacuum to be created in conditions such as an overnight cold soak or while driving and the purge system is active. If the NVLD never detects a switch state change between open and closed as vacuum is expected to build, one of these codes will be set, depending which system is actively being tested at the time. To have all three (especially the P0440 "general failure") code almost always means there is a problem with the NVLD unit or wiring going to it.
I wouldn't expect the NVLD to be completely disconnected or smashed at this point because a P0499 NVLD control circuit code would be present if that were to happen. It's more likely that the NVLD unit has suffered a failure with its internal vacuum switch mechanism or you have a leak large enough to prevent any sort of vacuum accumulation in the evaporative system. A fuel odor will likely be noticed if that's the case.
The most likely place to find an evap leak on these units will be very near the NVLD itself, which is about even with the driver's door handle under the vehicle and shifted toward the same side of the car. NVLD is a 3-wire unit with two large 1/2" diameter hoses connecting to it.
While not expected here, a complete blockage of the vent side of the NVLD unit can produce these same codes. Venting occurs on the large U-shaped hose , ending at a black plastic canister about the size of a can of beans right next to the NVLD. You should be able to blow through the hose from NVLD to the vent and if it flows freely... it's not a venting issue.
Examine the wiring at the NVLD for breakage or pull-out in case they happened to encounter a road hazard of some sort. Once again, the chances of wiring damage without setting a P0499 are slim, but need to be checked.
If you can see no visible damage to any of the lines, NVLD or vapor canister (large black plastic unit with hoses coming out near NVLD), I'd expect the NVLD to be bad. Further testing with the factory scan tool to monitor switch state and the ability to evacuate and smoke test the system for leaks add certainty points to the diagnosis, but I'm doubtful that you have these specialty tools lying around. =/
Replacement of the NVLD requires minimal hand tools, needing only a flat-blade screwdriver to release the plastic mounting tab and maybe to help pry the hoses off. Be careful to avoid splitting or tearing the hoses as that will create the sort of leak that the system is designed to detect.
Once replaced, you can clear your codes manually with a scan tool or by doing a battery disconnect of 30 seconds or more. The next few days will tell the story as to the effectiveness of the repair as the lamp either comes back on or doesn't. Conversely, you can leave the codes intact and drive it the same amount of days, watching to see if the MIL goes OUT as the vehicle tests and accumulates good trips... positive testing that shows no evidence of failure.
Let me know if you have any questions or problems and I'll get back to you as soon as possible. I'm at work today but will keep an eye out for your reply.
Dang. The GASCAP prompt in the message center is basically the same thing as a 1-trip failure of the evap system. It still thinks there is a problem.
It's odd that you're only now getting the GASCAP message. Did it ever tell you this before?
That's the way it should work. The GASCAP prompt gives you time to correct a left-loose gas cap before it turns into a full-blown trouble code. All it takes is a couple Good Trips afterward and the warning goes away. The GASCAP warning actually can't be erased directly, needing an OK from the Evap Leak Monitor after it's actually seen these Good Trips even if the problem is fixed.
We might have to do some improv at this point. Testing of the evap system doesn't lend itself to outside-the-dealer circumstances as you can imagine. Do you have a way to lift the vehicle high enough to do electrical testing right at the NVLD? We'll need a digital multimeter as well....