Mechanics

WHY WOULD TPS SIGNAL WIRE HAVE 4.8 VOLTS COMING FROM THE ECM? IS THERE A LIMP MODE THAT DOES THIS OR IS IT A SHORT COMING OUT OF THE ECM?

2000 Dodge Neon • 165,000 miles

My understanding is that this wire is read by the computer and there isn't supposed to be voltage coming out of the computer through it. I'm not sure if the car will do this for a reason or if I have a short. I get the same results with two different computers so I'm pretty sure it's not the problem. Should I start testing every plug on the car with an ohm meter to find a short. I have been digging on this for quite some time... Please help.
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Pelwynf2009
April 23, 2012.




Computer sends a 5 volt signal down the line to the sensor. There is a ground wire and a sensor return wire back to the pcm.

Roy

ASEMaster6371
Apr 23, 2012.
I understand, when the sensor is unhooked the sensor return wire reads 4.8 volts from the computer. 5 volt supply wire and ground wire are normal.

Tiny
Pelwynf2009
Apr 23, 2012.
That is normal also.

Roy

ASEMaster6371
Apr 23, 2012.
So, testing the tps plug with the key on and the tps unhooked I have 5 volts, 4.8 volts, and ground. That's normal? Why would the computer send 4.8 volts out the signal wire. Shouldn't that wire be an input to the comp not an output?

Tiny
Pelwynf2009
Apr 23, 2012.
The return signal when hooked up will lower the voltage back to the pcm.

Roy

ASEMaster6371
Apr 23, 2012.
I noticed that earlier. Thanks, as long as I know that it's acting normal.
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Tiny
Pelwynf2009
Apr 23, 2012.
Good luck

ASEMaster6371
Apr 23, 2012.

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