Lxjoshxl

Hi, I’m having an issue with my tps it’s 2001 Silverado 6.0 drive by cable. The sensor will show normally in the data logger but when I hold it wide open it goes to 100% then drops to 50% and continues to do so like a heartbeat. Tried multiple different sensors not sure if anyone else has ran into this issue

91 Z28

iTrader: (3)

Get a multimeter and start checking wires

Lxjoshxl

So at gray there should be 5v constant? Black is ground and the other is signal wire?

Lxjoshxl

I have 5 volts and 12 volt when I jump to ground it bounces up and down from 100 percent to 50percent

91 Z28

iTrader: (3)

I didn't know a TPS could have 12v it should only be a 5v sensor. Are you sure you've got the right harness plugged in??

91 Z28

iTrader: (3)

Pin A: Grey - 5 volt
Pin B: Black - sensor ground
Pin C: Dark Blue - TPS Signal

You'll take the red probe on the multimeter and go to pin C and the black probe to ground (battery or chassis) then open and close the throttle

Lxjoshxl

Pin a gray is 5v
blue and black I probed the positive to see ground and it’s -12v on the blue and black so that would be it’s completing a circuit?

91 Z28

iTrader: (3)

Black is the only ground. The Blue wire is your TPS Signal the ECU will see. Sounds like you've got other problems you need to get sorted

Lxjoshxl

Could a bad pcm cause this issue?

91 Z28

iTrader: (3)

Possibly, try another PCM and see if it fixes the issue