How do you test the PCM?

[marktruck]

How do you test the PCM? how do you know its bad?
thanks,
marktruck

[bringselpup]

I imagine the dealership has the ability to test them.

A common symptom of one going bad is a start sequence that begins to get longer and longer. Because what is really happening is that the PCM isn't telling the fuel pump to do the brief prime burst to pressurize the fuel line so you can start up. If you sit in the seat, turn the key only to on, you should see the Check engine light and the abs light go on for a sec and hear the pump spin for a moment.

If this does not happen, just sit there and wait to hear the pump go. You will hear this buzz/hum from the back by the gas tank. Once you hear the pump, try to start the engine. If it fires right up after hearing the pump it's very likely the PCM. I had to do one a little over a year ago and the symptom was a longer and longer wait before hearing the pump spin.

I made sure it wasn't my fuel pump by opening the PDC and taking the cover off the fuel pump relay and manually activating it to be sure the pump was running if it was told to.

[marktruck]

(I made sure it wasn't my fuel pump by opening the PDC and taking the cover off the fuel pump relay and manually activating it to be sure the pump was running if it was told to.)

How do you or,which terminals do you jump to activate the pump?

thanks,
marktruck

[bringselpup]

Pull the relay out of the PDC and pop the plastic cover off it with a really small flathead screwdriver or a dental tool. Put it back in without the cover and it will be obvious what portion of the relay to move to make contact.

When I did it I found that the circuit was live even with my ignition off so be careful not to short anything and use a pencil or something to push with.