Ive looked about the interwebz, but it seems that Google doesnt know the difference between Dodge and Ford/Toyota and any other non-Dodge word.

I plugged my truck up to a code reader and got:

P0751
P0420
P0443

P0751 is Shift Solenoid A, and everything I read on it (mostly from other cars) was that it could either have a valve stuck, or it could be the fact the my OD on/off switch died. Has anyone else had this issue and hopefully a solution?

P0420 is Catalyst Efficiency is not within levels. Which makes sense since I may or may not have one.

P0443 is Evaporative Emission Control. I havent a slightest clue about this one.


I have a:
1998
3.9 V6
4 speed auto

Any ideas would be awesome.

 

0443 is classic. It's just a vacuum leak somewhere between the engine, charcoal canister, and fuel tank.

0420, make sure you have a catalytic convertor. Sounds like one might be plugged

0751, i don't know about.

 

P0751 (M)_ O/D Switch Pressed (Lo) more than 5 Minutes Override switch input is in a prolongated depressed state.
P0751 (M)_ O/D Switch Pressed (Lo) more than 5 Minutes Overdrive off switch input too low for more than 5 minutes (4-speed auto. Trans. Only).

If your OD switch is on your column shifter, replace your column shifter/OD switch from a salvage yard/parts recycler.

If you don't have a cat, you would have been getting this code ever since the cat was removed. You will get better gas mileage if you have a bad cat and replace it. Take a peek underneath. It'll just be a fat object in the exhaust tubing (besides the muffler).

The evap situation could just be a hose has gotten cut or pulled off. Crawl underneath and look around your gas tank and check all of the tubes that are in the area in front of it and run towards the engine bay. Then check the condition of the fat tubes in your engine bay.

 

I guess I shouldnt have been so non commital earlier. The cat was cut long before I got the vehicle.

As to my OD switch, it quit working a while back, and when I tried to replace it the wires pulled apart. I just have them isolated and pushed over now. I figured as long as they didnt hit and engage the OD off all would be good.

The metal hoses from the tank to a black box (I assumed the aforementioned charcoal filter?) look fine. I cant look at it because I have nerf bars in the way, but there used to be a rubber hose hanging off of it. Is there supposed to be a hose running from the cat to the box, I guess to pull overpressure off of the exhaust and feed it back into the motor? I heard my grandad mention that that happened sometimes. Dunno.

So all in all, its nothing to worry about? Or can the OD switch cause some major issues down the road?


Also, I know the tranny has been overheated a time or two before I got it.

 

you're thinking of the old evap system style, diluting the exhaust with other air.

The lack of a cat is triggering the O2 sensors fault, so that explains that code.

the evap is a set of rubber lines from the tank to the black box, and the black box up to the throttle body (i believe). They rot out fairly easily, so most of us have the 044x codes memorized as being a rotted or cracked line.

 

I got under it as best as I could and i only saw metal lines. I'll see if I cant get a better look in the morning.

 

I think the OD switch replacement/repair is worth looking into. At least consider your options. Good luck.