so in my efforts to diagnose and fix this problem that I have I learned that the throttle position sensor may be the issue. Cool it’s a nothing part. Relatively inexpensive or so I thought. I’ve recently learned that you can’t just replace the throttle position sensor and after talking to the dealer, I have to replace the whole throttlebody at the cost of $2397.

So let me tell you what’s going on. I have the sport model with paddle shifting on the steering wheel those don’t work, however neither does the cruise control because I assume the clock spring needs to be replaced. But that’s not even what the problem is.

The problem is that while driving, the car will just suddenly downshift or upshift at a very improper time whenever it does this the little tiny display in the tachometer lights up with the gear that it has shifted it into. I remember the same thing would happened before when the paddle shifters did work. I would be in drive mode and then with the paddles downshift or upshift and it would light up with what gear I was in.

So honestly, I don’t know if the problem is the clock spring shorting out and electronically/manually shifting up or down while in drive mode. Or if the TPS is sending wrong signals and making the car shift down or up almost like gear hunting. But if it is gear hunting, why is it lighting up the display as if the paddles are being touched?

very confusing. I did find a 2007 fit in a junkyard that I can pull the throttlebody off of. but I’d rather not go replacing a part if I don’t need to. Maybe I could just clean it or reset the TPS?
Any help would be greatly appreciated.
and before anybody says check the archives I did look and everything seems to be all mixed up. People are talking about their second GEN in the first GEN forum and so on.
thanks.

 

The throttle body is a drive-by-wire system, where the throttle plate is controlled by a servo motor. When you step on the gas pedal, you're moving the accelerator pedal position sensor, which tells the ECM how much power you want. The ECM then shifts gears and commands the throttle plate according to conditions, to get the desired acceleration. The throttle servo has (at least) two TPS sensors - if the sensors don't agree, the ECM throws an error code (check-engine light) and probably goes into limp mode. If you're not getting throttle position sensor error codes, your throttle body is fine.

Deal with the cable reel/clock spring first. Maybe somebody pinched a wire during one of the airbag recall services. The airbag needs to come out to remove the steering wheel to replace the cable reel - point being to give the steering wheel wiring harness a good looking-at while you're in there. I don't have a wiring diagram handy, but it wouldn't surprise me if the steering wheel controls all shared a common ground wire - that's also worth checking.

 

Oh! Great point about the steering wheel controls sharing a common ground. That’s probably what’s going on. It makes sense b/c sometimes when turning the wheel the “cruise main” light illuminates on the dash. And it seems to shift up/down more when the wheel is being turned. I headed to junk yard today to pull a new “cable reel” or clock spring so when I take mine apart I have it if needed.
thanks for the info about the throttle body, I thought it was weird that I wasn’t getting an error code for a possible sensor malfunction.
Cheers

 

Sounds like you're aware, but be careful about keeping the cable reel/clock spring centered when you remove it. Center the steering in the junk yard car, then put a zip tie through the center of the reel to keep it from accidentally "winding up" or "unwinding" in transit. The "reel" and "clock spring" names come from the long flat electrical cable wrapped up inside. It can only rotate so many turns in each direction before the cable runs out of slack, bunches up and damages the wiring. That sort of damage could also cause the problems you're seeing.

 

So to follow up with this little project, after replacing the clock spring, aka cable reel, it has completely fixed the problem. When I pulled the old one out, it had was so dirty and grimy.
It’s odd to think that this would have caused the car to shift up and down erratically. But sure enough all better now. And bonus my cruise control is operable again! Yay.

 

I may be late to the thread. Doesn’t Acuity make a TPS sensor?

 

You stated above that you have paddle shifters. The signal for up/down shifts goes through the clock spring, so it's not surprising that you had unexpected shifts.