I have had a SES light for a while now but been neglecting it. Just recently, past week or two, i've noticed that the transmission hesitates when pulling away from a stop and periodically when placing into park the rpm will accelerate slightly then drop back down. Then yesterday my wife said that the overdrive light was flickering. I'm assuming that my trans problems have to do with the P0720 code, so change that sensor?
The P0670- i have an 2000 Diesel excursion so I know it's the GPCM but i havent' found a good way to trouble shoot this thing. The engine seems to run fine outside of the transmisison problem so I was suprised to see this code.
Any recommendations would be great.

 

TSB 03-21-36 on FTE web site. Hopfully this will help, i don't know to create a link sorry!

Let us know what you find, i had the same problem with my 2000 X only i had one clyinder the was not glowing, one day i was looking at our 2005 X and it has the same GPCM on it so i swaped it out and it started like the day i bought it new so i replaced it. I just googled it and it came right up!

Good Luck!

 

Thats for that, i'll take a look and see what i find. Question, where is the PCM? Is that the one behind the stereo that is almost impossible to reach. If so, is their a way to check the voltage at the GPCM for the test vs. at the PCM.

 

I think the pcm is behind the kick panel on the drivers side by your left foot. You might want to clear the codes and see if it shows up again, it might have had a brain fart one day

 

i've got multiple problems so i'm trying to figure it all out. It looks like it will be easy enough to do the test like the bulletin calls for. Now i just have to figure out where this Output shaft sensor is and how i'm going ot get to it. 4x4 excursion, i think i found it but I have no idea how i'm going to get in their to test it, let alone replace it. The transmission is acting wierd so hopefully this will fix it.

 

OSS is on the top rear of the tranny



PCM is the square box next to the e-brake pedal as mentioned.

GPCM wiring is as follows

 

Are these sensors all the same p/n. Also, Chris with that picture does that apply to the 4wd vehicles as well?

 

I don't think they're the same part #. Location should be the same for 2wd & 4wd. One sensor measures RPM on the input side of the tranny, the other measures the RPM's going out the back end to the drive shaft.

 

I can't seem to locate the p/n for that sensor anywhere. I've a few places where people have said that all three of these speed sensors are the same but looking the VSS and then based on how the OSS feels they don't feel like they are the same. I think i found it on the transmission now i just have to figure out how to get to it.

 

So i put in a new glow plug module and a new OSS sensor. Took care of the 720 code but I still have the 670. Has anyone trouble shot this before that could step me through the process. I have read the bulletin and it talks about using a break out box, which i obviously don't have. Thier has got to be a way to check this without having to take it to the steelership.
Also, does anyone see any issues driving the truck with it throwing the P0670 code. It seems to run fine.

 

P0670 Glow plug Control Circuit Error. Being that the GP's only come on to start the truck I wouldn't think this would be an issue. Here's a bump so someone more knowledgeable can get back to you.