how can i test my egr switch?


thanks
If you don't have a vacuum pump device, unplug the electrical connector to the EGR Sol. under the front of the plenum and start the engine. Then connect one side of the Sol. to ground and jumper the other side to the + battery terminal. This will simulate the ECM command to the EGR Sol. and cause it to apply manifold vacuum to the EGR valve which should then open.
You can even clip a DMM lead onto the top of the EGR Temp. Sw to see if it pulls the EGR feedback line to ground as exhaust gasses reach it and heat it. Before the EGR Temp. sw closes the reading should be +5Vdc.
This will give you a nearly complete analysis of the EGR circuit, except for the ECM control signal to the EGR Sol. But it should be enough to isolate the problem.




