The throttle position sensor is probably one of the easiest engine management system components to test.
It can be tested with a simple multimeter, no scan tool required! In this tutorial, I'll explain how to test it in a step-by-step manner.
You'll be able to easily find out if it's bad or not with 3 simple multimeter tests.
Contents of this tutorial at a glance:
You can find this tutorial in Spanish here: Cómo Probar El Sensor TPS (1995-1997 2.7L Honda Accord) (at: autotecnico-online.com).
NOTE: This tutorial applies to the following vehicles since they use the exact same throttle position sensor:
- 2.7L V6 Honda Accord: 1995, 1996, 1997
RELATED TROUBLE CODES:
- P0122 -What Does It Mean? (1996-1997 2.7L Honda Accord).
- P0123 -What Does It Mean? (1996-1997 2.7L Honda Accord).
Symptoms Of A Bad Throttle Position Sensor
The throttle position sensor has the job of measuring the amount the throttle plate opens as you step on or off the accelerator pedal.
The way it works is that the throttle position sensor produces a voltage signal that increases as you step on the accelerator pedal and the throttle plate opens.
When you step off the accelerator pedal and the throttle plate starts to close, the TPS voltage signal decreases back to its original base voltage.
All of these throttle plate angle changes are constantly reported to your 2.7L V6 Honda Accord's fuel injection computer.
Since the throttle position sensor (TPS) is such an important component of the fuel injection system of your 1995-1996 2.7L Honda Accord, when it fails you're gonna' definitely feel the engine resent it.
You're going to see the following TPS diagnostic trouble code lighting up the check engine light:
- P0122 TPS Voltage Too Low.
- P0123 TPS Voltage Too High.
You can find out more about what these trouble codes mean here:
- P0122 -What Does It Mean? (1995-1997 2.7L Honda Accord).
- P0123 -What Does It Mean? (1995-1997 2.7L Honda Accord).
You're also going to see one or more of the following symptoms:
- Won't pass the state mandated emissions test.
- Bad gas mileage.
- Lack of power, rough idle, or hesitation.
- Engine cranks a long time before starting.
Throttle Position Sensor (TPS) Circuit Descriptions
Below are the circuit descriptions of the 3 wires of the throttle position sensor's connector.
| Terminal | Wire | Description |
|---|---|---|
| 1 | Green with blue stripe (GRN/BLU) | Ground |
| 2 | Red with black stripe (RED/BLK) | TPS Signal |
| 3 | Yellow with blue stripe (YEL/BLU) | 5 Volts |
Where To Buy The TPS And Save
The 1995-1997 2.7L Honda Accord's TPS is a pretty inexpensive component. The following link, to a well known national brand name (Dorman), will help you to comparison shop and hopefully save you a few bucks on its purchase:
NOTE: The above throttle position sensor (TPS) fits the following vehicles: 1995, 1996, 1997 2.7L Honda Accord.
TEST 1: Testing The TPS Voltage Signal
As mentioned before, the TPS signal voltage increases/decreases as the throttle plate opens/closes.
So, to find out if it's good or bad, we're gonna' connect a multimeter to the TPS signal wire and see if the signal voltage increases/decreases as you open/close the throttle plate.
The signal wire, that we need to connect the multimeter to, is the red with black stripe (RED/BLK) wire of the TPS 3-wire connector.
IMPORTANT: The throttle position sensor (TPS) must remain connected to its electrical connector for this test to function properly. To be able to access the voltage inside the signal wire, you'll need to use either a back probe or a wire piercing probe. You can see an example of this tool here: Wire Piercing Probe.
Let's get started:
- 1
Place your multimeter in Volts DC mode.
- 2
Connect the red multimeter test lead to the RED/BLK wire of the TP sensor harness connector.
The RED/BLK wire is identified with the number 2 in the photo above. - 3
Ground the black multimeter test lead directly on the battery negative (-) post.
- 4
Manually rotate the throttle plate.
You'll get the best results by opening and closing the throttle plate directly on the throttle body instead of stepping on the accelerator pedal. - 5
The multimeter should show an increasing voltage as you (or your helper) open up the throttle plate.
You'll get the best results by opening and closing the throttle plate directly on the throttle body instead of stepping on the accelerator pedal. - 6
The multimeter should show a decreasing voltage as you begin to close the throttle plate.
- 7
Using a screwdriver's handle, gently tap the TP sensor as you open and close the throttle plate and observe the multimeter.
The purpose (of tapping the TP sensor with the screwdriver's handle) is to see if the TP sensor shows gaps in the voltage signal. Why? Because a good TP sensor will show a continuous increasing or decreasing voltage signal even while getting tapped by the screw-driver's handle.
Let's analyze your test results:
CASE 1: The TPS voltage signal increased/decreased as you opened/closed the throttle plate. This is the correct test result and it indicates that the throttle position sensor is good.
With this test result you can also conclude that the TPS sensor is getting both power (5 Volts) and Ground from your 2.7L Honda Accord's fuel injection computer.
CASE 2: The TPS voltage signal DID NOT increase/decrease as you opened and closed the throttle plate. This test result usually indicates that the TPS sensor is defective.
To make sure the TPS sensor is bad the next step is to check that the red wire is feeding the TPS with 5 Volts. For this test go to: TEST 2: Making Sure The TPS Has 5 Volts.
CASE 3: The multimeter DID NOT register any voltage. This test result usually indicates that the TPS sensor is defective.
To make sure the TPS sensor is bad the next step is to check that the red wire is feeding the TPS with 5 Volts. For this test go to: TEST 2: Making Sure The TPS Has 5 Volts.
