How To Test: Throttle Position Sensor (Ford 1.9L, 2.0L)

The throttle position sensor (TPS) is one of the easiest sensors to test on your Ford 1.9L or 2.0L 4 cylinder engine.

The best part of testing the TPS is that you don't need any expensive tools. You can test it with a simple multimeter. Yep, no scan tool is required for the TPS test.

Also you don't need to remove the TPS from its place on the throttle body to test it since it can be tested while its still on the engine.

In this tutorial I am going to explain the whole test in a step by step manner.

Symptoms Of A Bad Throttle Position Sensor (TPS)

Your vehicle's computer needs to know how much the throttle plate opens, when you step on the accelerator pedal, so that it can inject more fuel.

It also needs to know when the throttle plate closes, as you're letting your foot off of the accelerator pedal, so that it can inject less fuel.

So, when the TP sensor fails, the fuel injection computer isn't able to effectively control the amount of fuel injection (and a host of other things) and you're gonna' feel it as you drive your vehicle down the road.

Here a other symptoms of a bad throttle position sensor (TPS) your Ford vehicle may experience:

1. Trouble codes lighting up the check engine light (CEL):
   • Code P0120: Throttle Position (TP) Circuit Performance Problem.
   • Code P0123: Throttle Position (TP) Circuit High Input.
   • Code P0122: Throttle Position (TP) Circuit Low Input.
2. Hesitation when accelerating your vehicle down the road.
3. Intermittent lack of power when accelerating.
4. Bad gas mileage.
5. Extended cranking time.
6. Idle lopes (idle RPMs go up and down).

Basics Of The Throttle Position Sensor (TPS)

The throttle position sensor (TPS) is located on the side of the throttle body.

As you're already aware, the throttle position sensor (TPS) on your 1.9L or 2.0L equipped Ford has 3 wires coming out of its connector.

Each wire starts and ends at the fuel injection computer (known in today's tech lingo as the Powertrain Control Module = PCM).

Each one carries a specific type of signal and in this section I'll briefly go over each one.

NOTE: You'll notice in the descriptions below that I did not include the color of the wires. This shouldn't worry you because the circuits are the same regardless of the color of the wires on your specific Ford model. (as long as they're covered by this tutorial -see the ‘Applies To:’ box on the right).

TPS circuit descriptions:

• Circuit labeled 1:
  • Ground (provided by the PCM).
• Circuit labeled 2:
  • Throttle Position (TP) Signal Circuit.
  • The TP signal's voltage increases as the throttle angle increases.
  • The TP signal's voltage decreases as the throttle angle decreases.
• Circuit labeled 3:
  • Power in the for of 5 Volts DC (provided by the PCM).

START HERE: Throttle Position Sensor (TPS) Tests

As I mentioned at the beginning of the article, testing the TPS on your Ford vehicle is it hard but you do have to keep certain safety precautions in mind and these are:

• The TP sensor has to remain connected to its connector for the tests to work. This is because the connector will provide both power and Ground (with the Key On Engine Off) for us to test the sensor.
• All three TP sensor wires connect directly to the PCM, so be careful and don't short them to 12 Volts or you'll fry the computer.
• The TP sensor test is done with the Key On Engine Off (KOEO).

The tests in this tutorial are:

1. Checking that the TPS is producing a increasing/decreasing voltage signal.
   • This test simply involves connecting your multimeter to the correct TP sensor wire and manually opening the throttle as observe the voltage reading the sensor is creating.
   • TEST 1: Checking The Throttle Position Sensor (TPS) Signal.
2. Making sure that the TPS is receiving 5 Volts and Ground.
   • TEST 2: Checking Throttle Position Sensor (TPS) Power And Ground.