LT4 Check engine Light

[C4 Collector Edition]

we have a 96 LT4 that we cannot seem to track down the what the issue is with the Check Engine Soon light. Car has been stored so I am just beginning the search. we did replace a O-2 sensor. 2 years ago we had to put in a new fuel pump and assembly. That was done while on road trip and it seems like the Check engine light became an issue after that. Any experience or advice would be appreciated.

 

[Hib Halverson]

What fault codes are set?

 

[C4 Collector Edition]

Will have to take car to Chevy dealer and have codes ran . might get that done in the next few days.

 

[C4 Collector Edition]

Attempted to have code(s) ran at two different Auto Stores. A total of 3 instruments between both stores could not connect. Their thought is the ECM is not communicating with or through the terminal connection. They could not help me. I think I am going to have to take the Vette to a Chevy dealer or a shop that can perform diagnostics through the ECM...if anyone has had this issue or has suggestion please share I would appreciate.

 

[Kevin Doyle]

Tuner

Someone might of had it reprogrammed or aftermarket programmer would it cause this?Just a thought,Kevin.

 

[jcdouglass]

no diags?

When is the last time you had a saftey inspection? Has the conn pin ever worked? I used to unhook the battery. If light comes back on , you have a real problem.

 

[redvett]

The ALDL port is powered by the liter circuit, check the fuse.

 

[gmjunkie]

Attempted to have code(s) ran at two different Auto Stores. A total of 3 instruments between both stores could not connect. Their thought is the ECM is not communicating with or through the terminal connection. They could not help me. I think I am going to have to take the Vette to a Chevy dealer or a shop that can perform diagnostics through the ECM...if anyone has had this issue or has suggestion please share I would appreciate.

Start Here............................................

Remove Battery,Clean and Inspect "ALL" Body,Chassis and Engine Grounds and the B+ connections at power distribution blocks and fuse pin's!

Then go from there!

I find Non-Existent or High Resistance Grounds as the major culprit on these cars,I clean allot more wiring connections than replacing electronics!

I rarely have to replace electronic components!

 

[C4 Collector Edition]

thanks everyone. Looks like I have a punchlist of ideas I can work through. Appreciate it.