I had posted this under Diamante, but I think ths forum has more of the tech help.

I own a 97 Diamante that has set a P0120 Code indicating a failed throttle position sensor. Before I spend the money for a replacement (>$100 USD), I would like to confirm the failure. Is there an way to read the voltage at the sensor? If so between what wires? Between what values would the sensor be set as idle?

I have been to two bookstores and two autoparts places and they do not have either Chiltons or Hayes in stock,

my E-mail is artsemail@comcast.net.

Thanks for the help

Art

 

has it been running ok??

 

The idle is high and when you are stopping the car gives a little jerk and the RPMs jump up a couple hundred RPM. Other than at idle, the car runs fine.

Art

 

Maybe yours is the same as mine on the Talon.

This is a 3 terminal potentiometer.

If you disconnect it and measure resistance it should range like any potentiometer resistor.

If you check the voltage with the ignition on, you should see 5volts (supply B+)
on one pin, 0 volts (ground conn.) on the other pin and 0 to 5volts variable on the third pin as you vary the position.

Sometimes you will get the code if the 3 pin plug works its way loose, or I even seen it appear when the 5 volt source in the ECM went bad (this will give you a less than 5volt source @ the sensor, low like about 1 to 4 volts ) or else if the 5 volt source in the ECM looses its regulation then it could also go high and result in a reading of 11 or 12 volts @ the sensors.

This is not good because sensors operate on a regulated source of 5V for accuracy.

You are right to troubleshoot this before buying a new sensor because probably the throttle position sensor itself is O-kay as these do not usually break.

Does it need adjusted to find a good range ? Maybe try loosening the bolts then centering the mechanical range to match up with your accelerator position so that the sensor can range a true 0v to 5v increase or decrease.

Hope this helps.

DT

 

The Diamante uses a four pin TPS. The computer looks for switch closure at idle. I now have the pin out and checked the TPS. Resistance appears to be good with no drop out (hard to tell on a digital VOM but do not have an analog one). The switch read high for the closed position. I read over 150 ohms. I believe it should be close to zero. Looks like I need a new TPS.

Thanks for all the responses.

Art

 

If you have 12v to it, you've definately got something wrong.

You should be reading .9 ohms and 4-5volts.