EVAP and EGR ready monitors will not reset after multiple drives. Perhaps I have not met all the conditions but I have never had this issue with this vehicle before. So I am going to show my ignorance here (again).

Over the last few days, I have had pending codes P0171 and P0174, pending but not stored with no CEL. I also had one instance of the message to "Check Gas Cap". Yesterday. I cleaned up the gas cap, made sure it was seated properly and the message cleared after a short drive and there were no pending codes. So early this morning, I took it for a long drive, hoping for the best.

When I returned, I had pending code P0174, no CEL and no other issues. As I understand it, the CEL will not illuminate unless the condition is severe enough to warrant it. And a pending code is just 1 instance of the problem.

My question is: Would this pending code prevent completion of the EVAP and EGR readiness monitors?

 

As they keep coming up as pending you probably have a fault, which may be marginal. Do the usual checks for fuel trims & air leaks.

Lots of codes and fault conditions disable or are disabled by OBD monitors or other codes. There are fairly detailed docs on this but short of the actual software source code I'm doubtful we have access to the entire details. Doesn't generally seem to matter, though.

 

Just doing the easy things first. Found no obvious leaks but they would probably not be obvious anyway. Cleaned the MAF. Air filter needed changing badly. Noticed some missing until warm but no misfire codes. Spark plugs are long overdue so I'll check the coils and replace the plugs. New gas cap on the way. Running some injector cleaner now. We'll just see how it goes.

I just need to get this inspected. This is the last year I expect to keep it.

 

Ran from a full tank to 1/4 tank. Partway in between, I added a bottle of injector cleaner. The missing seems to have cleared up but I fueled up again a bit over half tank and added another bottle of injector cleaner. Drove 30 miles. EVAP and EGR still have not set and P0174 popped back up as pending. All codes had been clean from the previous 2 drives. I'll just continue to go through drive cycles until the parts on order show up. This car has 137k and I'm the third owner. To my knowledge the plugs have never been changed. I'll work down the list of the usual causes. Probably a smoke test is next.

 

You need to discover the source (s) of the air leak that is leaning out the mixture: air tube for cracks; poorly fitted throttle body; leaking oil filler; loose manifold . . . .

 

SOLVED! Took another look under the hood and discovered that the hose coming from the fuel tank was not connected to the short rubber lower EVAP valve inlet. From the driver's side (USA), one can only look down on the hose. In my case one hose was on top of the other and it looked like they were connected. I did not run my fingers over it because there is not much space to get a hand in there. But from the passenger side, it was obvious that it had become disconnected. So with a bit of struggle, I secured the hose and drove a very short drive cycle. It was enough to clear the Jag P1000 code and ready up the EVAP monitor. Only the EGR monitor remains but I can get it inspected as is. I'm sure it will ready up with a proper drive cycle.

Now I can get back to the mundane things (as soon as I get it past inspection).