P0122 Acura RSX – Test TPS Sensor

P0122 Acura RSX – Test TPS Sensor


The RSX TPS sensor in your Acura is also known as the K series throttle sensor. It can also be called the throttle position sensor as well. This potentiometer style sensor is mounted into the throttle body, and it’s primary duty is the convert the angle of your throttle body into a voltage your engine computer understands. In other words as you open the throttle or apply pressure to the gas pedal, this sensor reads how far the throttle is opening. Today I’ll be showing you how to correct the P0122 Acura RSX trouble code in a 2.0 liter.

Your Acura RSX engine computer is also known as the ECU. It takes the signal from your RSX TPS sensor and uses it to deliver the right amount of fuel to your 2.0 liter DOHC i-VTEC engine. When the RSX TPS sensor goes bad or there’s a problem with your TPS sensor wiring, your Acura will run poorly.

How to Test Acura RSX TPS Sensor 122

The reason for your Acura RSX problems are due to the RSX TPS sensor not functioning. Because your RSX ECU won’t know how much air is entering the engine, fuel delivery will be rough to say the least.

Today I’ll be showing you how to test the RSX TPS sensor in a 2003 Acura. If you have an existing K series swap this test also applies to you.

When your RSX TPS sensor goes bad or your ECU sees a problem, your RSX check engine light will turn on. In order to read the stored Diagnostic Trouble code, you’ll need the right OBDII scan tool. Although you can use your scan tool to erase the RSX trouble code, you’ll need to test or fix the TPS before the P0122 Acura RSX will be cleared. The translation for this P0122 Acura RSX code is Throttle Position Sensor Circuit Low Input.

Symptoms of a P0122 Acura RSX trouble code

When the throttle position sensor in your RSX goes out, there’s several RSX issues that will arise. Some of these related P0122 Acura RSX problems are below.

  • Bad throttle response
  • Poor gas mileage
  • RSX won’t start
  • Poor RSX idle

Fixing your P0122 Acura RSX code

In order to test the low voltage signal in your TPS, you will need to use a digital muitimeter. You will be using this meter to test the voltage that’s being sent to your Acura ECU or engine computer. Before you can do this however, you’ll need to take some action to access the throttle position sensor.

Before you begin our guide to the P0122 Acura RSX trouble code, you should disconnect your Acura battery. Once that is done open the hood and locate your K series engine cover.

P0122 Acura RSX 1There are two 10mm bolts that hold the intake manifold cover in place. Remove these 10mm bolts to begin our P0122 Acura RSX tutorial.

Once the bolts have been removed in your engine bay, you can lift up to remove the K20 cover. Make sure to take care when removing the post that runs into the intake piping as shown below.

P0122 Acura RSX 33

Now that the K20 engine cover has been removed you can remove the intake piping. Before you do this however you’ll need to disconnect the RSX MAP sensor. This is the pressure sensor that’s mounted on top of your K20 throttle body.

How to P0122 Acura RSX 4

Unplug the manifold pressure sensor as shown above, and now you are ready to remove the RSX IAT sensor. Unplug the two pin IAT sensor to begin with and then you can unclip the temperature sensor.

P0122 Acura RSX 11

Now that is done you can start to loosen the worm clamps that connect the intake pipe to the air box and the RSX throttle body.

How to P0122 Acura RSX 12

Now with the intake piping taken out of the way, you can begin testing your TPS sensor signal. Don’t forget that the P0122 Acura RSX trouble code is for a low voltage error, so we’ll be testing the signal wire after checking for power and ground.

Reach behind the throttle body and disconnect the RSX TPS connector. Now prepare your multimeter by turning the dial to read voltage. Now insert your RSX ignition key and turn to the ON position.

How to P0122 Acura RSX 15

This powers up the sensors in your Acura RSX. The wire you will be testing is shown above in our RSX TPS sensor wiring diagram. The first wire you will be checking is PIN A, and this wire should be transmitting a ground signal for your throttle sensor.

If you have a ground circuit here, now check PIN C for a switched 5 volt signal. If you have power and ground here at these two pins, the last part of the test will involve you plugging the TPS sensor back in. The wire you will be checking is the middle wire, or PIN B.

Reconnect the TPS to fix your P0122 Acura RSX trouble code. Once the throttle sensor is plugged back in, strip back a section of the wire that goes to PIN B. Now leave the ignition turned to the ON position, and measure the voltage at this wire with the TPS connected. With the throttle plate closed, you should read between .7-.9 volts of signal. Now manually deflect the RSX throttle open, and at wide open throttle it should read between 4.4-4.8 volts of signal.

If your RSX throttle body does not respond correctly, it’s time for a replacement TPS. Replace your throttle sensor and calibrate it to clear and erase your P0122 Acura RSX OBDII code. Have any questions about our guide on how to fix a P0122 Acura RSX code? Leave us a comment below and let us know!