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Discussion Starter #1
my tps is reading too low voltage, it is at 4.705v on the voltmeter when i disconnect the plug and check it's reading, which should be 5v.

that means it isn't the calibration position of the tps but is actually based on the amount of power the battery is sending to the plug which powers the tps, i am stumped on how to increase the amount of power the tps is receiving, i thought i would just calibrate the thing.

any advice?
 

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If you do not have a 5vdc reference at the sensor, there is a bad wire or connection between the sensor and ECU.

... Philip
 

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Discussion Starter #4
[solved]

hey there, just in case anyone finds this, i want to share my solution.

i had some low voltage i couldn't calibrate the tps, always getting the nasty drive situation of weird revving, stalling before the engine warms up, ect.


i unplugged the tps sensor, wiggled around all the connections, cleaned all the connections, cleaned and resealed the electrical wiring running to the sensor from the battery, i cleaned out the housing between the throttle body and the sensor, then when i reconnected the sensor, i pushed it in so that it made contact with the throttle pin, checked my readings for 5 volts, tried to make have more voltage than less voltage, got it adjusted, cleared the code and the car accepted it as good, no more tps low volts. all clear.
 

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Sometimes it helps to have perspective.

The reality of your situation was that you were looking in the wrong place for the problem - 4.7v ~ 5v - on the supply line is pretty much the same thing to the electronics, and since the supply is coming from the ECU, it knows what to expect - your problem was that the voltage on the "wiper" connection of the TPS was too low.

The TPS sensor is what we call a potentiometer, or variable resistor, a three terminal electronic device, that most people are familiar with as the volume control on a radio - in this case one terminal is grounded, one terminal is connected to the "5v nominal" reference supply, and the last terminal is the "wiper" that moves as the throttle plate is opened and closed - the voltage on this last terminal will vary between 0v and the 5v nominal reference as the throttle plate is opened or closed - it's usually not at zero when the throttle is closed, but at some very small (<1v) - if the ECU sees it at zero at switch on, you'll get the error you're reporting.

What can cause it to go to zero? Look at Aqua's response above - you probably had a bad contact where the harness connects to the sensor.

Notice I keep saying "5v nominal" - that's because it's not actually 5v, it may be a little lower or a little higher - grab your meter and check the battery voltage on the car - that's a 12v nominal - and can be anywhere from about 11v ~ 15v depending on the batteries state of charge and whether or not the engine is running and the alternator charging the battery.
 
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