Truck sat for a couple weeks, now lots of trans codes and instrument cluster issues.

[Alex_M]

Hey all! Looking for a bit of help on what appears to be an electrical problem, but I'm not sure where to start diagnostically.

The truck sat for a couple weeks; lost the keys. The battery died during that time and it sat dead for the majority of that period.

A couple days ago a buddy needed to borrow a vehicle and I was going to loan him the Tahoe. Started it up, sent to pull out, and it felt gutless. Wasn't shifting. Only one gear. It's also having instrument cluster issues. No speedo, no tach, other funkiness. Video is linked below.

Tonight I hooked up and scanned for codes and below is pictured what I came up with.

This truck ran perfectly when I parked it. This is the vehicle my wife and I took to Colorado and back and it was solid as a rock. Has been since I built the trans right after I bought the thing about a year ago.

Now, to compound matters, tonight it died on my. It started up fine. I cleared codes and then tried to move it back and forth, acted the same is has the last couple days. Then it suddenly died. I tried to start it again and it would idle low a second and die again, repeatedly. Feathering the throttle only made it die quicker. It was pretty low on fuel when I parked it, so that is a possibility, but it would be a good coincidence. I'll throw a few gallons in it tomorrow night and see if that helps that specific issue.

If anyone has any suggestions it would be greatly appreciated. My fear currently is an ECU problem. I do have another ECU from a Silverado, but it goes along with a motor I have set aside for a swap into a Land Rover and I'd like to save it if I can.

Thanks everyone,

Alex

https://imgur.com/a/zMy3uUn

 

[Fless]

I'd say charge the battery and have it load tested. Your KOEO voltage looks pretty low, if the gauge is any indication.

 

[iamdub]

Hey all! Looking for a bit of help on what appears to be an electrical problem, but I'm not sure where to start diagnostically.

The truck sat for a couple weeks; lost the keys. The battery died during that time and it sat dead for the majority of that period.

A couple days ago a buddy needed to borrow a vehicle and I was going to loan him the Tahoe. Started it up, sent to pull out, and it felt gutless. Wasn't shifting. Only one gear. It's also having instrument cluster issues. No speedo, no tach, other funkiness. Video is linked below.

Tonight I hooked up and scanned for codes and below is pictured what I came up with.

This truck ran perfectly when I parked it. This is the vehicle my wife and I took to Colorado and back and it was solid as a rock. Has been since I built the trans right after I bought the thing about a year ago.

Now, to compound matters, tonight it died on my. It started up fine. I cleared codes and then tried to move it back and forth, acted the same is has the last couple days. Then it suddenly died. I tried to start it again and it would idle low a second and die again, repeatedly. Feathering the throttle only made it die quicker. It was pretty low on fuel when I parked it, so that is a possibility, but it would be a good coincidence. I'll throw a few gallons in it tomorrow night and see if that helps that specific issue.

If anyone has any suggestions it would be greatly appreciated. My fear currently is an ECU problem. I do have another ECU from a Silverado, but it goes along with a motor I have set aside for a swap into a Land Rover and I'd like to save it if I can.

Thanks everyone,

Alex

https://imgur.com/a/zMy3uUn

View attachment 355129

Any chance mice chewed some wires? Check your grounds! Start at the battery.

 

[04Z71w]

Any chance mice chewed some wires? Check your grounds! Start at the battery.

I second that...had that happen to my work truck sitting for 2 weeks on the side of the shop.

 

[OR VietVet]

What @Fless. @iamdub and @04Z71w said. Gotta start at the heart and make sure you have a GOOD battery and not one that is charged up. They don't like to be drained of juice and let sit that long. Mice/rodent chewing a definite possibility and check all the grounds.

 

[Alex_M]

Thanks guys! The battery is still good. It's pretty new, still holding charge good and cranks over fast so it's putting out plenty of amperage.

I'll do some digging through the harness and see if I can find anything. Are there any specific grounding points I should double check?

 

[OR VietVet]

Read thru this for help:

Fix the Chevrolet Intermittent Electrical Problem for Good

The Chevrolet intermittent electrical problem can drive you crazy. These vehicles intermittently lose power to the dashboard, radio and electrical system. See two causes.

www.fixmyoldride.com

 

[Alex_M]

I got it sorted out. I forgot to feed power to the small white wire in the ignition switch after converting to pushbutton start.

Thanks for everyone's help.

 

[OR VietVet]

The OLD "operator malfunction trick" ayyyy! Glad it is fixed.

 

[Alex_M]

Yep! Problem was between the seat and the steering wheel the whole time.