CANBUS question on voltage

[Whyjustwhy]

The way I understand it the Canbus system low side should be 2.5 V or below and the canbus high side should be 2.5 V or higher. At the resting state with no information being transmitted each side will have 2.5 V.

I am getting all kinds of canbus errors and I decided to rig up my multimeter where I could monitor the voltage while I'm operating and it's always 2.5 V on both sides no matter what's happening. Do you think this would trace back to a bad PCM or should I start checking modules?

 

[Richard320]

A multimeter doesn't react fast enough to read the signals on a CAN bus. You'd need an oscilloscope.

Look for any dealer add-ons that may have tapped into the CAN wiring. If anything starts to glitch, it can short the bus so nothing can communicate, which will set a whole slew of communication lost codes.

 

[Cbty2050]

Where are you tapped into? Your meter can help diag a communication fault, it works best for hard, constant bus drop outs/failures.

 

[Whyjustwhy]

I checked at the OBD2 port ground to Canbus high and ground to Canbus low.
I'm getting lots of electrical issues and warning lights on the dash. Lose all throttle response within 10 minutes of starting up the truck and it just revs up to about 1500 RPMs which allows me to continue moving but definitely not ideal or particularly safe. There's also a couple of fuses under the hood that seemed to not have power going to either side of them.