Chevy SS Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
56 Posts
Discussion Starter #1
Problem is no voltage present at can bus connector. I can't get my scan tool or HP tuner to talk to anything. Using a break out box I am showing no volts at the Battery port. Battery shows charged and I am reading 14.4 at every circuit panel, battery terminal and jumper terminal up front. Verified breakout box good on another vehicle.

Is there a circuit breaker that powers this? Where to start? I have the FSM and run some basic checks using a volt meter.

I swapped engines and had the car with out an engine for about 3 months due to the current world crap. I have put it all back together with no obvious crimps/breaks shorts in the wiring harness.. I've double checked the pins at the control module in the engine bay and nothing looks broken or missing.
 

·
Registered
Joined
·
110 Posts

·
Registered
Joined
·
1,131 Posts
Yep, looks simple, no power from the fuse if we are talking DLC. There are wiring diagrams on this site somewhere, I'm sure I've seen them.
Edit: here, look at power distribution, it shows F2 on this also.
Also, you mentioned pulling the engine? I would suspect a missed ground under the hood too. Perhaps just a connector. Does everything else fire up? like the dash ? There is a ground distribution PDF here too.

Break out box? On the PCM? No power there using the ground on the box too? how about using chassis ground? Man I bet you just forgot/missed a connector or ground.
Check for power and ground at the DLC too.
 

·
Registered
Joined
·
56 Posts
Discussion Starter #5 (Edited)
Thanks guys. I found the bad CB-- 20 or 2 depending on which FSM schematic I looked at. Got power.

SS Scott-- Did you know that not connecting your power steering rack will send you down a bunch of%^& rabbit holes??? I should have learned my lesson that this isn't fun from my last 2 cars...lol

Got comms. now I am dealing with a hard PCM fault.

Is our car one of those that you have to re write some modules if it has been left dead for too long?
 
  • Like
Reactions: SS_Scott

·
Registered
Joined
·
1,131 Posts
Thanks guys. I found the bad CB-- 20 or 2 depending on which FSM schematic I looked at. Got power.

SS Scott-- Did you know that not connecting your power steering rack will send you down a bunch of%^& rabbit holes??? I should have learned my lesson that this isn't fun from my last 2 cars...lol

Got comms. now I am dealing with a hard PCM fault.

Is our car one of those that you have to re write some modules if it has been left dead for too long?
Never heard of modules "forgetting". I think they would have some type of EPROM type of memory that doesn't loose anything because of power loss.

If all was well before you removed the engine, seems a good visual inspection of all the plugs, grounds, ect is the best bet.

I bet your PCM fault could be a power or ground problem too.....Check the voltage of the PCM with your scan tool.
 

·
Registered
Joined
·
14 Posts
Is our car one of those that you have to re write some modules if it has been left dead for too long?
Don’t know specifically about SS, but normally the computer must collect data for a certain period of time after power is restored. During this time, CEL is not set, but it will fail emission tests. A good scan tool will show whether it is ‘ready’ or ‘not ready’.
 
1 - 7 of 7 Posts
Top