Hello All!

After doing much research on here, I've found a few articles on this, but not much that turn up any information on the 2003 specifically, as it seems 04+ has a decent fix method of soldering a trace on the TCM.
After getting the P1716 Turbine revolution sensor code, it stayed for a few weeks and then after hitting a really big pothole it went away and i had my overdrive back. The next day it was gone again, so i assumed a loose wire somewhere.
From what research I've done it looks like my TCM is somewhere inside my vehicle on the passenger's side and a TCM re-flash might be needed.
I've dropped my pan and checked the wires (2 small 2 wire harnesses and two fat 10+ wire harnesses) and all seem to be fine and jiggling them around did nothing for it, but at least i renewed some fluid for now.

If anyone has any suggestions for the 2003 G35 Sedan please let me know, my only other option is to take it to a transmission shop for an expensive repair.

Thank You!
Mike

 

It's typically not a TCM issue, it's a valve body issue and yes it can affect the early models. They don't have the wire bussing like the 2004.5+ models, they use individual stranded/insulated wire, but the exact same thing can be happening and it also can be soldered.

It's also possible that your transmission is just starting to slip though, have you checked your fluid level lately? When you punch it WOT does it have a nice linear acceleration or does the engine rev but sort of stops pulling in 2nd/3rd gear?

 

It shifts hard from 1-2 and 2-3 so i go easy on it when starting out. The fluid was changed when I dropped the pan to check the 2 pairs of stranded insulated wires, and they are in good condition as well with no breaks and the connectors are nice and tight. Fluid level is ok.
The transmission shifts nicely with no slip, as long as i go easy on it. If I'm going in 4th gear and go WOT, it will just continue pulling in 4th and not down shift (at higher speeds) it will down shift at lower speeds though. If i go WOT from stop it will shift hard but still land the gears well.

Hope this answers your question
Thank You!
Mike

 

Sounds like you need to check your TCM ground wire, it's on the timing chain cover, very top, right in the middle. You'll see two wires landed on two separate bolts that are GREEN in color. Disconnect the battery, unbolt each, use a wire brush to clean up the lug, the threads on the bolt, the flange on the bolt where it mates to the 1-hole lug, and the aluminum mating surface on the timing chain cover. Then apply a small amount of electrical anti-oxidation grease to everything and bolt it back together.

 

I will do this with my wire brush dremmel, as soon as it stops raining, and let you know.
I really want to keep this car as I inherited it from my uncle a couple of months ago with only 92K on it. When it was his, I did most of the maintenance on it, but this one bewilders me.
I have a year to figure it out before my state inspection is due again, lol. I would also love my gas mileage back with overdrive, most trips are 4,500 RPM for 30-45 mins.

Thank You!
Mike

 

I've just done this, except the wires i see on the chain cover are all black, i'll show a picture. I've cleaned them all and applied anti-ox on them. I will take it for a ride in a little bit and let you know.



Thank You
Mike M

 

Yep those are the ones, the insulation on the wire is black yes, but the factory bolts are (or used to be, yours looks pretty oxidized) GREEN COLORED to signify they're grounding bolts.

 

OK, good. I took all of them off and cleaned them up. The issue is still persisting though.
Do you think it might actually need the sensor, or do we think the wire is broken somewhere between the sensor and the TCM in the passenger compartment?
Do you know the location of the sensor?
Also, I can manual shift up to 3 or 4 the first time I start it, but then it jumps to D no matter if it's in D or Manual mode until I turn it off and restart. Either way, still no overdrive.

Thank You,
Mike M

 

Hello All,

This has finally been resolved. After going to 4 different transmission shops, we have finally fixed the issue. The first two looked at it for 5 minutes and gave up. The third suggested replacing the TCM with a like version (this did not work). The final shop tried to order a re-manufactured valve body but found they do have them available anymore and purchased a low mileage used transmission and swapped out the valve body (The TCM is not attached to the valve body on this model) I believe the turbine revolution sensor is located somewhere in or on the valve body as this fixed the issue. Total cost was just under $900.

Thank You All For Your Input!
Mike M