i got the p1670 code which apparently is some failure between the pcm and idm i have a scanner so i can scan whenever i want to sometimes just because i am bored and this code isnt there all the time but does show up, i searched this and it seems everyone with this code has a no start issue. i have been trying to figure out a stutter at about 45mph , idle fluctuation when warm issue that is not constant but reoccurring, maybe the uvch harnesses? BTW there i do have some oil on the ICP connector but no codes on that and according to the scanner its doing what its supposed to. thanks for any suggestions.

 

I've been having an intermittent P1670 for about 6 months now. Everything I've read has pointed to a connection issue between the PCM, IDM and UVCH. One day soon I plan to pull the driver's fender insert (to get to the IDM), pull the connections for all 3, clean them and then reconnect to hopefully fix the issue.

I don't think I have a failure because, like you, my truck runs fine. It just occasionally throws the code and gives me the SES light. If I don't reset it, it goes away on it's own in a few hundred miles.

Just my .02. I hope it helps. When you do get it solved, don't forget to post it so the rest of us can learn.

 

It could have been caused by low battery power. I believe the cutoff between IDM and PCM is 10.1V... Try clearing the codes and then drive the truck. I would also test batteries and alternator...

 

Good call! The OP might be having that problem. I'm putting out 14.2VDC from the alternators and in the morning my Optimas are 12VDC so I'm pretty sure my issue is a connector. After 7 1/2 years and over 190K miles they are bound to get a little dirty!