2001 F550 no WTS, no tach

[two-lane]

Well, i've been having issues for the past 3 weeks almost now.

up untill today the truck would start fine cold, WTS worked, Tach worked.

Truck stalls after being run for 10 -30 mins

Won't restart for several hours.

I have done all the easy stuff

oil change, fuel filter, CPS, unplug ICP, rebuilt IPR.

When the motor cranks warm the ICP reads .5 - .55 volts

When cold cranked it reads .935 and fires up.

I read somewhere that the ICP is suppost to have 12 volts to it. Mine had 5 volts

So I jumpered a wire from the battery to the ICP and tried that.

Bad move. I read now that it should have 5 volts...

Now no WTS, no tach signal.

Changed out the CPS again and still no tach.

Checked fuses with DVOM and all zeroed out.

I should specifically check fuse 19, 22, and 30 again but I checked every single fuse under hood and under dash.

Did I fry my PCM trying to jumper 12v to the ICP?

[two-lane]

Double checked fuses, all good. What about the PCM relay in the engine fuse box? Could I have shorted that by jumping the ICP.

I tried to pull codes and my superchips would not connect.

It read codes yesterday, now after my lapse in judgement, it wont read codes.

How can I check the PCM with a DVOM?

[Patrick Feeley]

My guess is that the PCM is fried. Tach gets its signal from the PCM. I don't know if you can check the PCM with a DVOM, but I'll look at a PCED (Powertrain Control Emissions Diagnosis) manual to see what might be able to be checked (although I can only go to a 96 PCED and your's is a 2001. Cheers!