I have a 1998 Dodge Ram 1500 with 5.9L gas. I was driving home tonight and my pickup just died as I was cruising on the interstate. I was doing 80 mph (that's the speed limit here just fyi) and nothing was wrong according to my gauges or the feel of the pickup in general when it just died. I quickly threw it in neutral and coasted to the side of the road. Once I stopped, the check engine light came on.

I grabbed my computer and found 3 codes.
P0122- Throttle pos. sensor low input
P0505- Idle Air Control
P1296- No 5 Volts to MAP sensor

I tried resetting the computer and couldn't get it to fire. I haven't messed with it much, but figured I would see if anyone had any ideas.

I have tested the fuel pressure at the rail and am running just a hair under 50 psi so I have fuel pressure to the rail.

 

First and third codes are likely related, as I do believe they both get their five volt reference signal from the same source. (the pcm....) Work on those, then see if the IAC code solves itself.

Make sure you are getting five volts TO the TPS, and MAP sensors..... You can grab a service manual for your truck from here. Wiring diagrams are in section 8W.

 

After checking for the +5 volts supply voltage, check your wiring harness. Otherwise, it seems like the PCM is the common item here (bummer!).

 

Yeah I did some testing today and found I have no voltage to either MAP and TPS. I made sure I have 0 ohms between PCM and each sensor and I don't have voltage at the PCM so that means I am looking at a new PCM.

Anyone know of good performance PCMs for a 5.9 gasser? I've kicked around a chip, this could be a good opportunity.

 

I think mopar performance makes one. But, being as yours is OBDII, it is flashable to pretty much whatever you want. Just need to buy a tuner. You can likely get a pcm is most any parts store, but, it will have to be flashed to your VIN, else the ABS, and SRS will whine about it. I don't know if that gets taken care of when you order it, or something you need to deal with once its installed.

 

Yeah I've been searching all night and found a couple options. I called Summit Racing and the guy there said that he only had a Jet Computer/Chip that was # 90002 but a bit of research on it makes me think its a chip for the pcm, not a replacement pcm so I'm waiting to hear back from Jet on that.

Then found some on O'Reilly's and am trying to figure out if they request VIN and mileage then flash them or if they send them to me and I have to take it to a dealer to flash it...which we all know will cost around $100 so trying to figure that deal out.

I was looking at chips as well, thinking on maybe trying to ****** a Superchips 3815 on eBay at some point. I was hoping that I could maybe do some shift point mods but I seen someone mention that the TCM and PCM are separate, which means I can't do that with a chip but power gains are never a bad thing and my shift points might be alright now that I regeared it so looking towards that.

So currently I'm thinking it will be a stock PCM with hopefully a 3815 to give it a boost...and I hope that the PCM is my only issue, then maybe my pickup will see some exhaust and new rims in its future.

 

Well I found a pcm, ordered it and installed it and the pickup is back to life! All the codes are gone and she runs like a champ. Thanks for the help!

 

Great news Chetmotox!