Hi. I am new in this forum and to the Dodge Ram trucks. I bought a 2003 Dodge Ram 1500 5.7 HEMI and the original codes were for misfire 2 and 8. My mechanic troubleshoots and determined it was the PCM. I bought a PCM form the junkyard from an identical truck and upon connecting the new PCM, there were no issues until a few days after, when going in reverse, the ABS, brake, and Airbag lights in the dashboard come up as well as the beeping sound. The Check Engine light came up too.
This part is intermittent; the check engine will go away once the gear is changed to D or N. Sometimes, the check engine will remain on and the codes are P1687 and P1698.
Again, this is just when the car goes in reverse gear. Other than that, it drives well and the dashboard works well.
Just today, while having the Check Engine on for two days, I started the truck and the light was off, just like that and I went in reverse twice to get out of a parking spot and no beeping nor lights went on.
Any suggestions?
Thank you in advance for any help I can get.
Happy Holidays!!!

 

Close. You really wanna be in the Tech Section. I'll move this there for ya.

Was the PCM flashed to the correct VIN for the truck? All the modules chat together, and if they aren't VIN matched, they tend to whine about it.

 

I am sorry and thank you for moving my post.
According to the mechanic, yes, he did re-configured the PCM.

 

The codes are for different modules losing communications. It may be as simple as a bad connection somewhere. Maybe look at what harnesses get stressed when the truck is put in reverse. Maybe the engine torquing over a bit is pulling something loose? (it sounds a lot like just a connection problem to me......)

 

I was thinking the same thing but I just don't know where to look. When the reverse gear is engaged, where in the truck should I look?

 

Have someone else put the truck in gear, you watch under the hood, pay attention to any wiring harness that moves when the truck is put in gear. Make sure it has enough slack that it isn't trying to pull out any connectors/grounds. Probably have to switch from park to reverse several times to actually see anything..... and even then, ya never know.

 

Hi. I did what you suggested but I could not find or see anything being moved while the gear changed.
I continued to drive the truck and what I noticed was that after driving it for a couple of miles, I guess when the truck was warmed, the light (Check Engine light) went off and I try a couple of times to go in reverse and nothing happened. The next morning I drove the truck and when trying to get out of my driveway, I went in reverse and the light went on along with the beeping sound and the instrument going crazy. I just ignored it and continue my journey with the check engine on. I drove about 40 miles, parked and left the car parked for about 15 minutes. When I come back, I turned the truck on and the light was off, I tried the reverse and nothing happened.
I guess, this is only happening with the truck of cold or not warmed up to the normal temperature?
I checked all the fuses and everything looks good. I could unplug every single electrical connection just to check. Would it be a particular electrical connection that I can start with? Or will there be another suggestion?
Your help is greatly appreciated.
Thank you

 

Well the first code is for the cluster..... maybe check the connector(s?) on the back of the cluster. The second one is for TCM... they are both communication codes...... Seems the PCM can't talk to them. I don't have a manual, to see how everything chats together...... Would be a real handy book to have right about now.