How To Test The Throttle Position Sensor (1992-1999 2.2L Celica)

TEST 2: Verifying Throttle Position Sensor Has 5 Volts And Ground

If you've reached this point, your TP sensor did not pass TEST 1. Before you buy it and replace it, you need to make sure that it's getting both power and Ground.

This is a very fast and simple multimeter test. The two wires that you need to check for power and Ground are:

• The brown (BRN) wire, of the TP connector, supplies Ground to the TP sensor.
• On the 1992-1993 2.2L Celica, the wire that supplies power is the pink with blue stripe (PNK/BLU) wire of the TPS connector. On the 1994-1999 2.2L Celica, the wire that supplies power is the red (RED) wire of the TPS connector.

Now, if after checking and confirming that the TPS is getting power and Ground (after confirming the TPS did not pass TEST 1), then you can confidently conclude it's bad and needs to be replaced with a new one.

IMPORTANT: The PCM is the one that feeds this Ground to the throttle position sensor (TPS). Be careful and don't short this wire to battery voltage or you'll fry the PCM.

With your multimeter in Volts DC mode, this is what you need to do:

1. 1

   Verify that the PNK/BLU (or RED) wire has 4.5 to 5 Volts with the key on but engine off.
   
   A.) Connect the red multimeter test lead (using the appropriate tool) to the PNK/BLU (or RED) wire.
   
   B.) Connect the black multimeter test lead to the negative (-) battery terminal.
   
   C.) Your multimeter should read 4.5 to 5 Volts DC.

2. 2

   Verify that the BRN wire has Ground with the key on but engine off.
   
   A.) Connect the black multimeter test lead (using the appropriate tool) to the BRN wire.
   
   B.) Connect the red multimeter test lead to the positive (+) battery terminal.
   
   C.) Your multimeter should read 10 to 12 Volts DC.

Let's take a look at what your test results mean:

CASE 1: The TP sensor is being fed power and Ground. This is the correct and expected test result.

You can conclude that your 2.2L Toyota Celica's TPS is bad only if all tests have confirmed that:

1. The TP sensor IS NOT providing a varying voltage signal when manually opening/closing the throttle plate.
2. The TP sensor is being fed 5 Volts DC.
3. The TP sensor is being fed Ground.

You'll need to adjust the TPS assembly if you replace it. The following Toyota Camry tutorial explains the adjustment procedure: Adjusting The Throttle Position Sensor Assembly (this heading is found in the tutorial: TPS Idle Switch Multimeter Test (1992-1996 2.2L Celica)).

CASE 2: The TP sensor IS NOT being fed power or Ground. Double check your connections and make sure that you're testing the correct wires.

If your multimeter still does not show power and/or ground then you can conclude that there's an open in the wiring between the TP sensor harness connector and the PCM's harness connector. In the extreme of cases, the PCM has an internal problem (although this is very rare).

Although testing these two conditions are beyond the scope of this article, you have now eliminated the throttle position sensor (TPS) on your 2.2L Toyota Celica as being the cause of the problem and/or the TP sensor diagnostic trouble code (DTC) lighting up the check engine light (CEL).