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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29515
Experience:  GM Grand Master Technician 2007. 14 years experience.
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Took off negative cable to change throttle body when I

Customer Question

Took off negative cable to change throttle body when I reconnected the cable no crank no start when in start position fuel pump turns on instrument panel warning lights, radio hvac also on remote entry parking indicator gages power door locks and Windows not working cleaned all Barry connections Battery is good as well as the starter and Altinator did the same thing when I changed the throttle body gasket I cleaned and tightened battery terminals started right up no codes r found 07 chevy silverado extended cab 5.3 2wheel drive
Submitted: 1 year ago via Mitchell1DIY.
Category: Chevy
Expert:  GM Tech (Cam) replied 1 year ago.

Hi there, I am Cam.

Sorry to hear about this issue. L:Et see what we can do.

First is to try a reset. Take the battery cables off the battery, hold the ends together for 10 seconds then attach them to the battery and see what happens. This will reset the whole vehicle.
If you have 2 batteries, then remove both and touch only one set.
This reset is more about touching the cables together when off the battery than taking them off. The act of touching them drains the capacitors and forces it to reset.

If this does not help, post your VIN so I can see some of the options your truck has.

Customer: replied 1 year ago.
Didnt work the vin# *****
Expert:  GM Tech (Cam) replied 1 year ago.

Ok, do you have the means to check for diagnostic trouble codes?

Customer: replied 1 year ago.
no codes came up the truck ran fine before I took off negative cable off I've even added another ground wire to the end of the head to the battery I've read numerous forums about trucks with same issue some say buy needs reprogrammed or replaced but I've not found anything info other than random forums that that could be the solution same thing happened when the throttle body was taken off to be cleaned tightened the ground terminals
and it started right up I've checked and cleaned both terminals along with ground wires in engine campartment
Expert:  GM Tech (Cam) replied 1 year ago.

Its possible that the surge when you connected it did damage the PCM. For this I would see if I could communicate with the PCM on the scanner. IF not then follow diagnosis for that, which is checking power, ground and the data line to the PCM. IF there is no issues identified then it requires a new PCM. This requires that scanner that views live data. Without that we are guessing.

Customer: replied 1 year ago.
I shouldn't have taken the battery terminal off then. How many cars or trucks have u worked on or heard of someone elses working on a car or truck have a serge burn out the pcm by simply re connecting the negitive battery cable when every repair manual and/or directions for replacement parts#1 thing disconnect the negitive battery cable. Personally ive never had it happen nor have I heard it ever happening curious to know how often this happens
Expert:  GM Tech (Cam) replied 1 year ago.

I have not worked one one personally with this issue but have assisted a handful of people with this issue. It is very unlikely and I can only assume the pcm was weak to start with if that surge took it out.

Customer: replied 1 year ago.
Personally I think the bcm would be effected before the pcm would u happen to know how to test the bcm
Expert:  GM Tech (Cam) replied 1 year ago.

IT could be the BCM As well, This is where testing with scanner and seeing which you can communicate with is the start.