Ive only known the brake switch to cause issues with torque converter lockup. The pcm. Has a built in voltage regulator and it is possible it is shot. I have seen people go through 3 refurbd pcms before getting a good one. Wherw did you buy the pcm? Was it new or a reman? Has it ran since the new pcm was installed? Check all your grounds and add some new ones for good measure. I would add 3, one to block, one to chassis and one to the tranny. Make sure your grounds on the power steering bracket is good as well.

Also if it was a new pcm then it needs to be programmed. They usually come blank.

 

Pcm was refurb from adnanced auto. They said it is pre flashed and needed the vin to order it. I have grounds from blick to firewall block to battery battery to body and battery to chassis. There is another from firewall beside brake booster just not sure where it goes.

 

Did you check the ground by the PS pump @ front of engine? that one caused all kinds of hell for me last week, including symptoms of a bad PCM.

 

Checked all grounds. Took them off dipped in baking soda water wire brushed and put back on with dielectric grease. Did voltage drop on all grounds and they are perfect. ALSO, put my pcm on a buddies truck identical to mine, and his fired right up perfect. So pcm is good but I still have power to obd2 but no link, no check engine light when first key on, and no five volts from computer to sensors. MAP, TPS, CSPS, and pickup coil are only getting 2.2v

 

Anyone have any input?

 

I assume you have also pulled all the fuses everywhere and checked them all with an ohm meter?

 

Yeah. All fuses good relays all check out. All the normal stuff is right. Its gettin to be twilight zone now. Everythings works EXCEPT 5 v from computer to sensors. I wont give up but its damn frustrating

 

New update. Put another engine wiring harness on today and still have 2v to csps pick up coil tps and map sensors instead of 5v. Any ideas now

 

all those sensor get their power from the PCM, check and see what voltage you are getting right at the PCM.....

 

See post #13 in this thread.