Error code question??
 

I have a 1705 tuner with diagnostics and I've been showing a few error codes that I hope I can get some help with.

For some time I've gotten a check engine lite error that is triggered by a 0683 error code (Glow Plug Ctrl Mod to PCM
Comm Circuit). It always happens when starting the vehicle. It will in time go away, but it intermittently comes back when starting. I asked a tech at the Ford garage and he said he had never heard of it before. I thought it might be related to the tuner so I ran stock for a while and the code still triggered once in a while. I didn't think it affected the vehicles operation until about a month ago when my Excursion wouldn't start. The truck had always popped right over. They way it eventually started - very rough - gave me the impression that the glow plugs hadn't functioned properly. It did this same thing once more about a week ago. All other times it starts fine. Any thoughts on what might go wrong in the glow plug system??

A second code 0470 ( Exhaust back pres sensor curcuit error) is now on along with 1000 (Monitorchecks not complete - more driving required). These codes won't clear, so I'm assuming there is some kind of a sensor problem. These codes don't trip the Check engine lite like the 0683 code does.

My Excursion runs great and I think the only affect has been the couple times it didn't start right up. I'm in MN and it was cold the couple times it didn't start.

Thanks for your help - Dan Ward

P0683 Glow plug diagnostic signal communication fault

On that I would suspect a bad wire on the glow plug relay, possibly corrosion in the main harness to the PCM, or an intermittantly bad glow plug relay.

P0470 Exhaust Back Pressure Sensor Circuit Malfunction

On that one either the sensor has failed or the tube the sensor is mounted in has plugged up with exhaust soot.