The three pin RSX TPS sensor in your 2.0 liter DOHC K series Acura is designed to read the angle of your RSX throttle blade. This sensor is mounted opposite of your throttle blade and cable, and works as a basic potentiometer. Your throttle sensor is mounted to the K20 throttle shaft and as your throttle body opens this sensor reads how far the throttle is being opened.
Your Acura RSX ECU uses this data to properly deliver the right amount of fuel. When this TPS sensor goes bad, your engine computer won’t know how to control your DOHC fuel curves. The problems that are caused from your Acura RSX TPS sensor going bad can lead to issues with your fuel curves or you may find your Acura RSX won’t start.
Today I’ll be showing you how to test your RSX TPS sensor in a 2003 Acura. In order to complete this test correctly you will need to use a digital multimeter. You will be testing the wiring harness that leads to your Acura RSX TPS sensor to determine whether or not your throttle sensor is working correctly.
When your TPS sensor fails you will see several common Acura RSX problems. These can range from annoying to serious although the most obvious sign is your RSX check engine light.
When your OBDII RSX check engine light is turned on, you’ll need a scan tool to read the trouble codes.
If your RSX check engine light comes back as a TPS related failure, you’ll need this guide to test your throttle sensor.
Some of the more obvious throttle position sensor trouble codes include P0122 Throttle Position Sensor/Switch A Circuit Failure. When your K20 RSX is showing this error, you’ll need to use this DIY guide to testing your RSX TPS sensor.
To begin open your hood and locate the throttle sensor. This sensor is located near your firewall and mounted opposite of your throttle cable.
Before you can begin this How To Acura RSX TPS sensor guide, you’ll need to insert your key and turn the ignition to the ON position.
This powers up the sensors in your K20 engine. Now disconnect the Acura RSX TPS sensor harness.
The first wire we’ll be starting with is the power wire. Refer to our Acura RSX TPS sensor wiring diagram below to see what wires you’ll be testing on the ENGINE side of the throttle sensor.
The Acura RSX TPS sensor wiring diagram to the left is shown from the SENSOR side.
Once you have the throttle sensor unplugged, you’ll be using your multimeter to check for power.
The wire that leads to PIN 3 is the VCC2 wire. This wire should be transmitting 5 volts of switched power with your ignition turned to the ON position.
This wire is a YELLOW wire with a BLUE stripe in it. If you have power here the next wire to check is the SG2 wire at PIN 1, which should be a GREEN wire with a YELLOW stripe in it. This should have a ground signal for your RSX TPS Sensor.
If you have power and ground at these wires, the next part of this guide is to check the Acura RSX TPS sensor signal.
Test the Acura RSX TPS sensor signal wire
The next part of this guide will show you how to test the RSX TPS sensor signal. Connect the black lead of your multimeter to the negative battery terminal, and reconnect the TPS harness. Now pierce the wire that leads to PIN 2 with the red lead of your multimeter.
With your throttle in the closed position, this wire should read between .5 and .9 volts of signal. Now manually open your throttle body until it’s fully open. Monitor the voltage at PIN 2, it should sweep slowly and smoothly until it stops between 3.9 and 4.5 volts of DC signal.
Now you can test the RSX TPS sensor by testing at the sensor itself. This part of the test will require you to unplug the RSX throttle sensor again.
Now turn the dial of your multimeter to read resistance. Probe PIN 2 and PIN 3 of the SENSOR to read the internal resistance with your throttle in the closed position.
There should be between 0.5 and 0.9 kΩ at these two wires. If this part of the test checks out, now connect your multimeter leads at PIN 1 and PIN 2.
With the throttle plate closed there should be around 4.5kΩ at these two wires. If your RSX TPS sensor does not respond in the following fashion you will need to remove and install a replacement throttle sensor.
You will need to calibrate the throttle position sensor once you’ve installed it for proper operation. Have any questions about our RSX TPS sensor testing guide? Leave them for us below and let us know!
What is procedure for resting light after new tps is installed.
Hi Rob,
You can either disconnect the battery, and turn on the headlights for a minute or so OR you can go with an ODBII reader to help you clear your RSX check engine light.
Good luck!
If it’s reading 3.3 when throttle body fully open
Is that a sign that it’s bad or when I turn it on and disconnect the tps and if it runs better are those signs it bad?? Because mine doesn’t go to 3.9 or 4.5 when opening it
Hi Jeiel, thanks for reading
If your TPS only reads 3.3volts at wide open throttle, then it’s not going to adversely affect your vehicle too much. You may want to play with the idle screw or adjust your throttle body stopper. You simply aren’t getting as much performance when your voltage reads that low. Does the TPS read fine at closed throttle?
Well it reads 0.45 at closed it doesn’t read 5v max 0.46 when just checking on the 3rd pin I ordered a new tps I don’t know if this will help because I turn my car on and it idles at 2500 rpm at cold start then when warm it idles at 1500 rpm it’s acting up ever since I changed the iacv . any ideas ? Very helpful if you help
And I have a check light that says p1122 throttle position higher than expected I’m guessing that is either recalibrate it or new tps??
Hi Jeiel,
I would test the signal from the TPS sensor first to see if it’s bad. As far as calibration, you’ll need an aftermarket one that has provisions for modification. This is the cheaper way to fix RSX TPS sensor problems.
Check into a BLOX or Skunk unit. Good luck!
Hi Jeiel, the replacement RSX TPS sensor should definitely help. Thanks for reading!
I replaced it before you wrote back but I didn’t know what brand to go with so I went with a cheaper one and it doesn’t seem to fit or make a click and my tb won’t read open to 4.50 when calibrating the tps to 0.48v it max open to 4.34 I believe so is it the cheap tps that won’t fix the issue . ?
Hi Jeiel,
unmount the TPS if possible and plug it into your wiring harness. What voltage do you get when you manually deflect the RSX TPS sensor?