2008 GXP 72,000 mi W/P0700 CODE HELP!!!!

**ray51** · 12-05-2015

I'm new to this forum and looking for info, experience and guidance as how to proceed. Last night as I was driving home I noticed the speedo needle started to freak out and frantically move around and then go to zero. It would stay at zero for a few seconds then start to freak out again. That was followed by the transmission acting up. This morning I drove it and the check engine light was on. The transmission wasnt shifting properly, the 1-2 shift was harder than usual and the 2-3 wasnt happening all the time. The check engine light gave me codes P0700, P0722, P0723. Checked the fluid this a.m. and the color and level were good. After reading what I could find this morning, it seems these transmissions are known to have problems. P0700 indicates TCM and I'm wondering how to proceed and if this is indicating and transmission rebuild etc. Is it possible that its not a trans rebuild and something else? The car has been relatively trouble free until now. Just had mufflers replaced 3 days ago and suddenly…….. One other thing, when the outside temp falls below 45, my brights come on when I hit the right hand turn signal, so thats nice. Anyone?

A concern I have is that because this is all codes and computers, a shop could tell me I need a rebuild when that may not be the case.

Any advice, info or experience is greatly appreciated.

**Fivefingerdeathpunch** · 12-05-2015

P0700 is just a run a mill code saying you have a transmission fault, otherwise the code really means nothing else.

The P0722 and P0723 are both for the same exact issue. They are for the Output Speed Sensor No Signal.

So you are going to want to look into the output speed sensor for the transmission, it's going to be why the speedo is freaking out and transmission doesnt know how fast it's going.

**ray51** · 12-05-2015

Originally Posted by Fivefingerdeathpunch

P0700 is just a run a mill code saying you have a transmission fault, otherwise the code really means nothing else.

The P0722 and P0723 are both for the same exact issue. They are for the Output Speed Sensor No Signal.

So you are going to want to look into the output speed sensor for the transmission, it's going to be why the speedo is freaking out and transmission doesnt know how fast it's going.

Thanks for the info. The speedo wasnt freaking out today, while I was out this morning it was obvious the transmission wasnt acting right or shifting enough.If it cant sense the speed that would make sense. I tried to manually shift it and the shifts were really hard so I just brought it home and parked it fearing I could damage it by driving it. So is my next move to get to someone with a legit TECH II device so they can look deeper at things like the OUTPUT SPEED SENSOR etc?
Again, Thanks!

**Fivefingerdeathpunch** · 12-05-2015

If it was me, I'd take the passenger side tire off and inspect the speed sensor on the transmission.

It should be somewhere close the diff housing where the axle enter the transmission. Inspect the wires and connector. Or even just replace the sensor because a new AC Delco sensor is under $25.

**Fivefingerdeathpunch** · 12-05-2015

Pictures.

**ray51** · 12-06-2015

Thanks. Gonna check that today.

**jteske88** · 12-06-2015

i went from behind on mine, 20 minute job at most. the bolt on the back of the heat shield will piss you off

**ray51** · 12-06-2015

Indeed it did piss me off. Took me about an hour to get it out and about 5 min to put it back together. I took the car for a drive and it seems to be back to normal, had it out on the freeway and it was shifting like normal. THANK YOU for helping me out and the diagrams were very helpful!!!!!!!!! Im sooooo relieved that it was a quick inexpensive fix. The check engine light is still on, will it turn itself off after some driving or do I need to reset it? Grateful for this forum!!

**Fivefingerdeathpunch** · 12-06-2015

It will/should reset on it's own but it could take up to 40 drive cycles.

I'd go to a parts store that has a free code reader and just reset it. It's best to do it now just incase the light wants to pop back. Otherwise you'd have no clue if something else was going wrong if the light is already on.

**ray51** · 12-10-2015

Good morning. Well...... on the way to work this a.m. the same issues are back. About a half mile down the road the speedo freaked out again and the transmission shifts were hard and random. I made it to work thankfully. When I pulled the old
VSS out it had a fair amount of metal particles on it. The guy at AUTOZONE told me that the VSS works off of magnetism, is it possible that the new VSS has picked up more particles which may interfere with its operation? I had three days of what seemed to be normal transmission function and now its gone crazy doing exactly the same thing. However, no check engine light this morning. I suppose that could change the next time I start it.

**jteske88** · 12-10-2015

Do you have a cai? I would look around the pcm harness. I have had wires shaved down multiple times from my filter sagging. Just check wire color and go from there