I have a 90 GTA 5.7 I am getting a code 43 that is the Electronic Spark Control where is it located and if you have replaced this part where did you buy it?
Steve 706-594-8810

 

On my Camaro, it is located on the upper left side of the firewall, just to the left of the brake booster. It has a connector with around 4 to 7 wires IIRC, all in line. This should be a standard part at the local auto parts stores.

 

For the '85 - '89s the ESC module is where oscarfromla mentioned. CCC, TPI & TBI engines.

In '90, for the TPI cars, the ESC module was moved into the ECM.

The knock sensor is located in the block, in front of the starter, right above the pan rail. Note that the connector could have gone bad and fell off. This too will cause a code 43 in the '90 - '92 TPI cars.

You can test the sensor ('90 - '92 TPI) from checking the resistance between the center terminal and engine ground. Should be in the area of 3.9K ohms.

RBob.