Why am i not moving in 1st and 2nd?

[Robf]

Update.... got the new speed sensor in plugged it in and immediately I noticed it wasn't fixed. I'm also having some idle issues since cleaning the throttle body. I've tried doing the relearn procedure numerous times and can't seem to get it to idle right.

I have a new peddle assembly I'm going to try this weekend. I also have a laptop coming to try and get some more live data with the mpvi3 to see if I can get this figured out.

 

[Desert Sasqwatch]

There has to be a wiring issue somewhere between the speed sensor and PCM. Recommended checking connections end to end in the wiring and probably reseating the PCM connectors. If it's working with it disconnected, but not when plugged in, it has to be a crossed or shorted signal.

 

[Robf]

There has to be a wiring issue somewhere between the speed sensor and PCM. Recommended checking connections end to end in the wiring and probably reseating the PCM connectors. If it's working with it disconnected, but not when plugged in, it has to be a crossed or shorted signal.

When I got my wiring back I noticed the ground for the driver side brake light and license plate light didn't work. I ran it's own ground and now they work correctly. Also the auto light sensor isn't working. I didn't think these Issues are connected but maybe they are?

 

[jennam]

I'm also having some idle issues since cleaning the throttle body. I've tried doing the relearn procedure numerous times and can't seem to get it to idle right.

I had the same issue. It took several hours of starting it and trying to keep it running before the computer finally figured it out. Once it did, it calmed down and started running normally.

 

[Robf]

Hey you hp tuners guys can anyone tell what's going on during this short trip around the block a couple times. I plan on being able to get more data this weekend if iowa weather allows.

 

[Robf]

Thank you to Chuck for working with me through the tune. We figured out the issue. It was the brake torque limits tab now she runs like a top!

 

[comegetjoe]

Hell yeah! Thats teamwork!!

 

[Robf]

Hell yeah! Thats teamwork!!

Now that I think about it there may be more related to the brakes than originally thought. My guess is there is an issue somewhere in the harness that would tell the computer the brakes are active. Like previously posted when I installed the brake lights the drivers side brake light and the license plate light wouldn't work. I added a seperate ground and now it works fine. Does anyone know where the brake lights wound ground to? I had df do the wiring. So I'm not as familiar .

 

[Robinjo]

I want to say just back to one of the ground ring terminals that attaches either under the fuse box, by there steering column or by the battery. Under the fuse box makes more sense to as it’s the shortest path but I’m by no means electrically proficient.

 

[Gtstorey]

It’s not going to be an issue with the actual light wiring. I’m pretty sure that the brake lights are triggered by a signal from the BCM, which is itself triggered by the pedal. I’ll check the service manual when I get home.

 

[Robf]

It’s not going to be an issue with the actual light wiring. I’m pretty sure that the brake lights are triggered by a signal from the BCM, which is itself triggered by the pedal. I’ll check the service manual when I get home.

The weird thing was on the wiring in back the passenger light worked right away. The drivers side light as well as the license plate light didn't work until I gave them their own ground. Then it worked. If anyone has pinout all data for the 07 cobalt ls that would be awesome. Now that everything is working correctly it's not a huge deal I just don't want there to be an electrical fire or gremlins that plague the car.

 

[Gtstorey]

It’s very possible that DF missed a ground for the lights on the driver side. I just don’t think it has anything to do with the power issue.

 

[Robinjo]

Harnesses are hand built, even for OEM car manufacturers. Mistakes happen, trust me here.

 

[Robf]

It’s very possible that DF missed a ground for the lights on the driver side. I just don’t think it has anything to do with the power issue.

Let me know what you find in your service manual.

Harnesses are hand built, even for OEM car manufacturers. Mistakes happen, trust me here.

Oh I'm not saying this is a DF mess up at all they have been absolutely amazing in the whole process and have been very helpful. I'd like to find the root cause. Instead of just telling the computer not to listen to it. I don't want to be mistaken, Adam has helped a ton as well as Lonny talking to me on the phone for almost an hour trying to find data issues. I'm very impressed with their customer service to say the least. I'm just happy it's drivable now!

 

[Gtstorey]

My later model service manual has no tie from the brake lights into the Ecm. The brake pedal position sensor ties to the bcm which triggers the brake lights, The bcm also can talk to the ECM so I assume that it relays brake position over the network.