Im measuring the TPS voltage right now and with the key in the on position it reads. .39 volts. It fluctuates though between .39 to .14 etc...it becomes steady then fluctuates again...

Is this a bad sensor? I still have a low voltage code and the car seems to miss or stumble at very light throttle...

 

Well mine reads .86 Volts at idle(blades closed) and I know for sure .39 is too low which is why u are getting that code..adjust the tps and you should be fine..
I had to adjust mine when I put my BBk TB on..

Cody

 

Alright I just measured between the black and gray wires with the key in the on position and the harness connector off and I got 1.0 I measured between the blue and black again and got .39...but it wasnt even connected to the sensor???

Does this all mean anything?

 

I have, Ive sloted it just about as much as I can...Ill try to readust again....

 

New development...I went to move the sensor forward and the voltage doesnt go above .39....

 

Im just going to try a new sensor I guess....I dont know what else to do...

 

Do you have any kind of scanning software like FreeScan or anything? AutoTap should have it also...Just have a friend watch the voltage and you adjust it..the tps is just a "pot" which means it varies resisitance depending on which way you turn it..When mine broke you could turn it one way and it would stay..it should return back unless the spring/coil is broken..


Cody

 

On my scanmaster i get a constant .60 at idle which the scanmaster book says it is what it should be..........................go figure.



Chris

 

A 0% throttle position TPS voltage of 0.39 volts is just fine. However, it fluctuating down to 0.14 volts without you doing anything is NOT!!! The fluctuating down to .14 volts is what is giving you your SES code... not the steady .39 volts.

Sounds like a bad spot in the sensor. If not a bad sensor then it could be a wiring issue. Check the wires at the sensor and also at the PCM and make sure all connections are tight before spending money on a new TPS sensor.

 

The TPS is a potentiomater
a variable resistor.
A Low input voltage or poor ground will cause a low voltage on the return side

you have 3 wires, but I cant re-member off hand which is which

Refrence
signal
ground

The computer send a 5 volt refrence to the TPS. this is regulated by the PCM. As long as you have a good high impedance multi-meter you can measure voltage between refrence and batt -
This should be very close to 5 volts.
Figure out which is ground.
On the resistance setting on your multimeter measure resistance to ground
should be .1 ohm but would probibly work ok with .2 or .3
Do not measure resistance from refrence to batt -
this creates a direct path for high current to flow through the ECM to ground. that can fry the computer. In the Voltage setting your meter acts as a resistor and only lets a very small amount of current pass through, thats why I said "If you have a good meter" up above. really anything other than a 10$ walmart meter should be ok. The wire you were seeing .39 volts on was the signal wire. If I remember right the PCMs normal range is .9 - 4.X
so your are out of range. I should warn you that is usually NOT a bad TPS. More times than anything its a ground. Try keyon and check signal voltage at WOT should be 4.X might want to look up the actual spec here.

Also make sure all electrical connectors going back to the PCM are secure/dry/not corroded.


You can test the TPS by connecting you multimeter to the refrence and signal pins in the resistance function and actuatiing the throttle and watching for a range of resistances. compare to OEM specs.
If all of this fails and you havent done any mods lately I would condem the TPS. Any mods that touch your throttlebody, computer or electrical system. Including subs could be responsible. If you installed any of this lately disconnect it and see if that fixes your problem.

 

.3v-.9v is supposed to be acceptable for key ON, startup 0% throttle position. Like Brent said, if it is dropping down or fluctuating, that's no good.

 

Well I went to autozone and had the TPS tested, and it failed. As you rotate it the signal comes on slowly, flickers, than dies...

Ill have to get a new one tommorow...

Thanks for all your help guys..

 

Well I got a new one on and it looks like everything is better. The code is gone, and the car drives much better and is gettting much better gas mileage....

 

cool. glad I could help.