Then cap's description of "grounded" includes every single electonic unit that uses power.
It's just not true.
Grounding Vref and having it not affect an ecu only applies to two wire sensor which are resisted to sensor ground from the 5v feed.........or 8v in the case of many chryslers which feature both 5v and 8v reference voltage lines.
In those cases, you will see the reference voltage being lower depending on how much resistence there is.
In a 3 wire sensor, the regulator works to keep the Vref at a constant 5v relative to sensor ground.
Like I said before, I've rebuilt thousands of ford ecus as well as supported all of the products of Standard Motor Products and Blue Streak.
This includes dpfe sensors and the ecus we receive when a mechanic with a bad DPFE sensor sends it in to us.
The reasons I was diagnosing these is a bit different from Tiggers experience because I was brought in after technicians had already spent considerable time diagnosing and had already thrown an ecu at the problem as if it were a magic bullet that would fix thier woes.
I did no brakes or anything else but diagnose electrical issues related to the products that blue streak and standard motor products sells.
In the case of shorted to ground dpfe and other sensors, we either saw an ecu that had no errors and tested good or found the 5v regulator burned out because it was trying to push 5v direct to ground.
I know the runtime algorithms and ecus down to each and every component.
Hell.....I wrote the test proceedures on the newer ford ecus as well as many sensors for standard and blue streak.
