I have an '05 Z51 M6. Normally I shift to reverse before I shut the car off so the electronic shutdown sequence can run its course to finally shut all of the accessories off and lock the steering. I stop at a gas station the other day, press the off button and the DIC indicated "Shift to Reverse". Thinking I had missed "R" and hit 5th, I slam it to the far right and push up. Still get the message. I decide I will deal with this when I get home, get out, close the door, get the obnoxious triple honk from the horn and the doors won't lock.

I get back in, cranks right up. I have all ten fingers and all ten toes crossed that this was a fluke and everything would be okay when I got home. Sadly, this wasn't the case. Pull in and get the exact same behavior. I know I was in reverse when I parked because I always back into my parking space.

First thing I do is hit the forums and to no surprise I am not the only one who has this issue. I'm glad I read some post before taking action, because if I was unable to shut the car down I was going to pull the battery leads. This, according to other post, is not a good idea. Once power has been removed, the car will not start until shifted into reverse. Meaning, if you can't get it to recognize reverse, you are looking a towing bill.

I have seen other post that mentioned the person walked away for a few minutes, came back and was able to get the car to shut down. This is case with mine. It may take several visits, but I can eventually get it to recognize reverse. The difference between myself and the gentleman that wrote the post, is his rarely did it. Mine does it every time.

I have found that shifting to neutral before I shut it off, wait for the "Shift to Reverse" message, then shift to reverse seems to work better than just cutting it off while in reverse. My reverse lights are on when my parking brake is down and I'm in reverse.

Now that you are tired of reading this post, I guess I only have one question. I want to replace the reverse sensor. I know there is a reverse sensor on the passenger side of the T56 transmission, but is this the sensor the body control module uses to verify the car is in reverse? My reverse lights working, but the signal not making it to the BCM has me wondering if there are two different reverse sensors. One for the lights and one for the computer. Can anyone verify where the BCM reverse sensor is located?

Thanks in advance for your help.

 

There are 2 sensors on the '05 T56 trans. One for the BCM, the other for the Column Lock. I have no personal experience so here's a thread discussing a trans swap, '06 into an '05 car, and the hassle with those 2 sensors. Others may have more details.


http://forums.corvetteforum.com/c6-t...swaps-wtf.html


And though this doesn't affect you here's a follow-up thread to the one above just for info.

http://forums.corvetteforum.com/c6-t...-help-pls.html

 

Just a little update to what is going on. I have found a temporary fix for my "shift to reverse" problem. When I shut down, I have the car in neutral and wait for the "Shift to Reverse" message in my DIC. I then shift fully into reverse using the clutch of course. The message still appears on the DIC. I then slowly move the shifter to the rear until the message disappears and I hold it there for a couple of seconds and viola. Total shutdown!!! It may take a couple of times to hit the right spot, but be persistent. This is the temp fix.

I hope to have the long term fix in the mail as I type. A new switch of course. The 2005 has two reverse sensors in the transmission on the driver side. They are stacked one on top of the other spaced by an inch or two vertically. I haven't changed it out yet, but I'm anticipating the switch to be above the fluid level so I don't get a face full of dexron. I will testing each of the switches with a digital multimeter (DMM) so hopefully the culprit will be evident. Attach the leads (usually red and black) to the two prongs on the switch. The DMM should be set to measure resistance. Touch the leads together and you should get a short (zero ohms on display) and an open loop when they are apart (0L on most displays). Using alligator clips to attach the leads to the prongs will probably be very helpful as you will need your hands to push on the mechanical side of the switch. Once the leads are attached, push the mechanical portion in and out and the resistance reading on the DMM should cycle between zero ohms and an open loop.

I'm totally speculating this is the correct way to test the switch as I have not personally done it yet, but I specialize in controls for Navy ship construction so I've seen a couple of switches I will report back when I have actually touched it.

Cheers!!!

 

Unfortunately as per my PM to you there is more to it than that. The switch may well pass the "switch open/switch closed" test but the problem in some cases is one of the switches internally grounds.

The 12v just runs to earth though the tranny then and never tells the BCM it's in reverse or more importantly never tells the SCLCM that reverse is selected. It is because of this failed logic in the SCLCM that the car will not shut down.

When I discovered the faulty switch on mine I could make it behave correctly by rotating the terminals slightly on the switch itself. By fettling the shifter you are probably just making the switch work correctly now and again as the pressure changes on the switch head.

You won't lose any oil by removing both switches. A deep 22mm socket will help immensely. You will see how poorly they are built when you remove them.

It really would be the easiest thing in the world to bypass, you could even loop both into one switch.

Cheers and good luck.