1991 5.2 RWD. I have a code popping up as 12. But my FSM doesn’t list a 12 in it that I’ve seen. Anybody have any ideas?
I did switch to LED on the exterior lights and did not add any resistors and have an idea this may play a part in it.
The other code it’s showing is temp sending unit excessive,(can’t remember the code number off the top of my head). I do have it heating up and some days it almost goes to the overheat mark on the gauge. It sat for a couple years and on my first drive after doing the water pump it did overheat, but that was over a month ago and I believe close to 100 starts since then.
Thanks in advance for any and all ideas!
I just got back and checked the OBD & it’s codes are as I said before 12 and the other code is 22.
22 says coolant temp sensor input below minimum acceptable voltage or above maximum acceptable voltage.

 

12 is "Battery has been disconnected in the last 50 run cycles" (which isn't a start and turn it off, BTW, but a drive cycle of some sort - haven't found out what Chrysler wants for that.)

Perfectly normal if you've had the battery out.

Not so normal if it's been rocking right alone and all of a sudden kicks it.

(It's actually, to quote from my 1988 book, "Direct battery input to PCM was disconnected within the last 50 key-on cycles. " )

22 means the coolant temp sensor is either way low, or way high. And they're talking about the two-wire ECT, not the one wire gauge sending unit.

I'd also check the wiring; my 1988's wiring insulation was shot for that run due to age, so I had to buy a pigtail and splice it partway up into the harness down the passenger side intake.

BTW - Save Dakota Trouble Codes (dakota-truck.net) in your shortcuts or favorites.

RwP

 

Once again, Thank You Ralph.
That explains most of it for me.
a couple of years ago I had parked the truck in our apartment complex and was doing a little work on it when I had extra time and didn’t want to drive it with expired tags. Some punks stole it and took the
stereo and battery then left it in another complex less than 6 blocks away, it was found about 4 days later while I was out of town. I know they were young punks because I had not cleaned out the IAC& had it disconnected and would have to power brake it to keep it running while at lights and such. There is a joke about car anti theft devices for the younger generations, the third petal. After that I took the battery out while I amassed the suspension parts. Once I did my suspension rebuild and brought it back home I was unhooking the battery nightly to keep it safe.
We moved out of that ghetto complex a couple of weeks ago, finally!!!!

 

You should have had code 55 too. That means end of test cycle.

 

It did but it does give that in the FSM

 

Doesn't all code reading sequences start with 12?

 

Actually, no.

Currently my truck will toss a 15, VSS voltage too high or too low, and a 55. But no 12.

RwP

 

Hmmm, mine always starts with a 12. Always has. I always ignored it and went to any codes that flashed before the 55. I think the 12 is a common snafu with those OBD1 readers. Lots of people get that 12 code first.

 

If the battery voltage drops enough, it'll trigger it.

It's not SUPPOSED to be the "always starts with" code, though.

RwP

 

12 just means the battery has been disconnected in the last X (50, I think...) key cycles. So yeah, if you disconnect the battery to reset codes, it takes a while for that one to clear. It won't turn on the check engine lite though.