[ChevyTech]

Clear the code by pulling the ECM fuses for 30 seconds and then reinstall the fuses. Make sure the key is OFF when you do this.

Check the code to make sure it is gone.

Then start the vehicle and see if the code 42 comes back.


A code 42 is set when the ECM loses communication with the distributor.

Code 42 can be set by a bad distributor module, a bad ECM or wiring problems between the ECM and distributor.

A bad distributor module is a common cause for this code.

Many stores like NAPA in my area will test the module for free if you bring it in.

Make sure when you install or reinstall the distributor module that you use heat sink compound/grease under it. The grease helps dissipate heat from the module. Without it, the module will fail.

Look very carefully at the terminals on the connectors that plug onto the distributor module. Make sure they are not corroded and the fit tight (wire terminals not stretched open).