Hi guys,I'm getting a check engine light on my 1996 xj12 , I checked with my diagnostic tool and it is indicating codes .. P0401, P0441, AND P1000. I'm finding that the engine is idling a bit too high and there is a sound like some part of the exhaust system is very lightly touching the undercarriage but this sound goes away after about 30 seconds of running ( wondering what a failing air pump sounds like). Any help would be great. Thx..J.

 

P1000 is just readiness incomplete. It changes to a permanent P1111 when the drive cycle monitors get satisfied. 441 is evap bank A. P0401 I think would be EGR, but the X305 doesn't have an EGR system.

 

Not sure what you mean by evap bank. Does the air pump sound like a rattle or vibration if its failing?

 

Evap bank A means the right side of the engine. Each side has its own vapor recovery. The engine takes in and burns stored fuel vapors via the purge valves after the engine is started.

The process above does not include checking the evap hose to the purge valve, and I think that is more likely than an electrical fault. The hose could split or break and that would set the code. Both purge valves are under the left side air intake box, you might have to take the box out. That will allow you to check the hoses and electrical connections. Sometimes a plastic hose connector has broken. You can follow the hoses to the intake connections on the engine.

Also the cruise control vacuum hoses and pump are located down there so you can check those out too. Not uncommon to have hose breaks or air leaks there.

The air pump makes a bit of a rattle when it runs, but nothing harsh. Of course if it quit you would get a code for that, probably P0410. Is that the code you meant instead of P0401? I don't think P0401 applies to the XJ12.