Odd P0443 CEL behavior

[brdavis9]

The basic issue is the P0443 code and the CEL, and no luck with getting the CEL to stay off. It's a 1996 XJ Sport (4.0L HO w/AT and AC)

Condition 1:

1. Turn key to on
2. CEL turns on
3. Start engine, leave running
4. CEL stays on; OBDII scan (with engine running) shows P0443 code
5. Leave running, clear code: CEL stays on, P0443 remains (as expected, I suppose)

Condition 2

1. Turn key to on (engine not running, CEL on)
2. Clear code with scanner; CEL turns off
3. Start engine (do not turn off first). CEL stays off. Run scan; result is zero codes
4. Turn engine off
5. Turn key to on (note - engine remains off): CEL turns on, scan throws P0443 code

Condition 3

1. Turn key to on (engine not running, CEL on)
2. Clear code with scanner; CEL turns off. Run scan; result is zero codes
3. Turn key off (do not run engine)
4. Turn key to on (note - engine remains off): CEL turns on, scan throws P0443 code

1. In a nutshell, the CEL and P0443 code do not seem to be related to a vacuum leak or a sensor issue:
2. The cleared code returns immediately when the ignition is turned off-and-on (engine not running)
3. Clearing the code with the ignition on turns the CEL off, and immediately starting the engine — without turning the key off — (and leaving the engine running, even) the CEL stays off (and running a scan doesn't throw a code)

I'm stumped. Anyone have any suggestions? (One thread on described a similar issue and mentioned a missing/blown fuse in 10; I haven't checked that for a missing fuse, but have checked for blown fuses in general.)

Notes:

1. I've replaced the evap' solenoid. No change.
2. I've replaced the gas cap. No change.
3. Hoses appear fine
4. Wiring appears fine
5. Everything works... though the headliner needs replaced lol
6. I've not done a smoke test... but since the CEL and code reappears when the key is merely turned off-and-on after clearing the errors, a vac' leak wouldn't seem to be the problem
7. The Jeep starts, idles, runs, and drives excellent: no apparent issues, ever. It's a DD... I pay attention to maintenance, and replace worn out parts.

 

[daletec]

Run the smoke test I seen them smoke from a worn throttle body.