The throttle position sensor, on the 2.2L Toyota Camry, is two sensors in one assembly. One part of the TPS assembly is an idle switch and the other is the actual throttle position sensor.
In this tutorial, I'll show you how to test the TPS part of the assembly in a step-by-step way.
The contents of this tutorial at a glance:
- Symptoms of a Bad Throttle Position Sensor.
- Circuit Descriptions of the TPS.
- TEST 1: Testing the TPS Voltage Signal.
- TEST 2: Verifying Throttle Position Sensor Has 5 Volts and Ground.
- Where to Buy Your Throttle Position Sensor and Save.
You can find this tutorial in Spanish here: Cómo Probar El Sensor TPS (1992-1996 2.2L Toyota Camry) (at: autotecnico-online.com).
NOTE: This tutorial applies to specific 2.2L Toyota Vehicles. Take a look at the Applies To: box on the right column to check application.
NOTE: If you need to test the idle switch portion of the TPS or if you need to adjust the TPS, take a look at this tutorial: TPS Idle Switch Multimeter Test (1992-1996 2.2L Camry)
Symptoms of a Bad Throttle Position Sensor
The throttle plate opens and closes, to let more or less air into the engine, when you step on or off the accelerator pedal. It's the TP sensor's job to measure how much it opens and report this throttle angle to your Toyota Camry's fuel injection computer.
Since the TPS is such a critical role in your 2.2L Camry's engine management system, when it fails you'll see or more of the following symptoms:
- If your 2.2L Toyota is OBD II equipped (1996+), you'll see one of the following trouble codes:
- P0120: Throttle Position Sensor Circuit.
- P0121: Throttle Position Sensor Circuit.
- If your 2.2L Toyota is OBD I equipped, you'll see one of the following trouble codes:
- 41: Throttle Position Sensor Signal.
- Hesitation when accelerating the engine.
- Lack of power.
- Bad gas mileage.
Circuit Descriptions of the TPS
The table below has a brief description of the 4 wires that make up the TPS connector.
|TPS Circuits (1992-1996 2.2L Toyota Camry)|
|2||BLU||Idle Switch Signal|
NOTE: The above circuit descriptions apply only to the 1992-1996 2.2L Toyota Camry throttle position sensor.
TEST 1: Testing the TPS Voltage Signal
The very first thing that we'll do, to find out if the TPS has failed or not on your Camry, is to check the throttle angle voltage signal with a multimeter connected to the sensor's black (BLK) wire.
If the TPS is good, then the voltage signal that your multimeter reports should increase as you manually open the throttle plate. This voltage signal should then decrease as you close the throttle plate.
If the TPS is bad, your multimeter will report a single value that won't increase/decrease as you open/close the throttle plate.
IMPORTANT: You don't need to remove the TPS to bench test it, since the instructions below are for an on-car test. Since the TPS needs to remain connected to its connector, you'll need to use a back-probe or a wire-piercing probe to measure the TP signal voltage.
Here are the steps:
Turn the key to the ON position but don't start the engine, and place your multimeter in Volts DC mode.
Probe the BLK wire with the RED multimeter lead. This is the wire that's identified with the #3 in the illustration above.
Ground the BLACK multimeter test lead on the battery negative terminal.
Your multimeter should report a voltage between .2 to .9 Volts DC with the throttle plate closed. If your multimeter doesn't, don't worry about it just yet, continue with the other steps.
Slowly open the throttle (by hand and from the engine compartment). The voltage numbers should increase as the throttle plate opens.
This increase in voltage should be smooth and without any gaps or skips. Once the throttle is wide open, your multimeter should read somewhere between 3.5 to 4.5 Volts DC.
Slowly close the throttle. As the throttle is closing, you should see the voltage decrease smoothly and without any gaps or skips, to the exact same voltage you noticed in step 3.
Lightly tap on the throttle position sensor with the handle of a screw-driver (or something similar, and I want to emphasize the words ‘lightly tap’) as you slowly open and close the throttle and observe the multimeter.
If the TPS is bad, the tapping will cause the voltage numbers to skip or go blank. If the TPS is OK, the tapping will have no effect on the voltage numbers.
Repeat step 6 several times to make sure of your multimeter test results.
Let's take a look at your test results:
CASE 1: The throttle angle voltage increased and decreased as you opened and closed the throttle plate. This test result confirms that the TP sensor is OK and not defective.
CASE 2: The throttle angle voltage DID NOT increase (and/or decrease) as you opened and closed the throttle plate. This test result confirms the throttle position sensor trouble code lighting up the check engine light on your 2.2L Toyota Camry.
If I where in your shoes and to be sure that the TPS has truly failed, I would still make sure that the TP sensor is getting both power and ground. To check for power on the LT GRN wire, go to: TEST 2: Verifying Throttle Position Sensor Has Power.
CASE 3: Multimeter DID NOT register any voltage, this test result doesn't condemn the TP sensor as BAD just yet. Why? Because...
... the TP sensor may be missing either power or ground. So the next step is to check that the TP sensor is getting power, go to TEST 2: Verifying Throttle Position Sensor Has Power.