Throttle position sensor issue
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Joined: Jun 2013
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Throttle position sensor issue
My throttle position sensor is reading backwards when I backprobe the sensor wire and the ground wire with key on . At closed throttle it is reading 4.5V and and at WOT it is reading .3V . The reason I am doing this in the first place is cause my truck is experiencing a rough idle and issues of misfiring when I get above 45-50 mph . In the middle range it seems to run just fine . Which in my mind makes sense to me in my mind if the TPS signal is flipped flopped cause I am getting way too much fuel at idle and not enough while a creating at higher speed and load . But I kinda confused on how it would fail like that because it is just a variable resistor . Correct ? Anybody out there have any experience with a problem similar to this .
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Joined: Jan 2013
Posts: 165
Likes: 13
Only thing I can think of is as you mentioned, yes it is a variable resistor and if the resistor has a "dead spot", then you may see a low value at certain points throughout the range......as for the high value off idle, could be a couple things.
Here is a good writ up for checking / adjusting your TPS with tuner and multimeter...double check everything again before you head out to get a new TPS.
T.P.S. Adjustments;
Via Diablo;
If you have a Diablo Predator then you don’t need pins or any special connector or volt meter.
Just plug predator in,
Turn key to on but don’t start it
Select Diagnostics
The scroll down and select Gas Trans.
Then select Choose From List
Scroll down and select TPV
Then select Fast Rate
Then Select NO for Data log
You will then see the TPV
You have enough cable on the predator to make it out of the CAB and into the Engine Bay so that you can look at it and adjust the TPS to .99.
Your T.P.S. is located on the front passenger’s side of the Plenum.
Once located Loosen the two mounting screws just slightly, you should be able to just turn it.
Clockwise will increase the number count and counter clockwise will decrease the number count.
An Alternative route;
Tools needed:
8mm socket & ratchet (to adjust idle set screw, usually not needed. 02 - 03 won't have the nut set screw)
Phillips screw driver (to loosen TPS screws)
Multimeter (to measure TPS voltage)
Pins (To stick thru the insulation on the wires to the TPS) - optional
How to check your TPS voltage:
Turn key on, but don’t crank engine.
Put positive lead of multimeter on Grey w/ White stripe wire (middle wire)
Put negative lead of multimeter on Grey w/ Red stripe (bottom wire)
One can use straight pins and poke them through the insulation. You can also use them to stick into the back of the connector as not to put holes in the wires.
Here is a good writ up for checking / adjusting your TPS with tuner and multimeter...double check everything again before you head out to get a new TPS.
T.P.S. Adjustments;
Via Diablo;
If you have a Diablo Predator then you don’t need pins or any special connector or volt meter.
Just plug predator in,
Turn key to on but don’t start it
Select Diagnostics
The scroll down and select Gas Trans.
Then select Choose From List
Scroll down and select TPV
Then select Fast Rate
Then Select NO for Data log
You will then see the TPV
You have enough cable on the predator to make it out of the CAB and into the Engine Bay so that you can look at it and adjust the TPS to .99.
Your T.P.S. is located on the front passenger’s side of the Plenum.
Once located Loosen the two mounting screws just slightly, you should be able to just turn it.
Clockwise will increase the number count and counter clockwise will decrease the number count.
An Alternative route;
Tools needed:
8mm socket & ratchet (to adjust idle set screw, usually not needed. 02 - 03 won't have the nut set screw)
Phillips screw driver (to loosen TPS screws)
Multimeter (to measure TPS voltage)
Pins (To stick thru the insulation on the wires to the TPS) - optional
How to check your TPS voltage:
Turn key on, but don’t crank engine.
Put positive lead of multimeter on Grey w/ White stripe wire (middle wire)
Put negative lead of multimeter on Grey w/ Red stripe (bottom wire)
One can use straight pins and poke them through the insulation. You can also use them to stick into the back of the connector as not to put holes in the wires.
