How To Test The TPS (1997-1999 1.6L Nissan Sentra)

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

If the TPS sensor failed TEST 1, then there's a possibility that it's lacking a supply of 5 Volts or Ground.

So, before concluding that the TP sensor has failed and needs to be replaced it's a good idea to confirm that it has power (5 Volts) and Ground.

The fuel injection computer is the one that supplies this voltage and Ground to the TP sensor. These are the wires you'll be testing:

• The PNK/BLU (pink with blue stripe) wire, of the TP connector, supplies 5 Volts to the TP sensor.
• The BLK (black) wire, of the TP connector, supplies Ground.

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 wire has voltage ( 4.5 to 5 Volts DC ) with the key on but engine off.
   
   1.) Connect the red multimeter test lead (using the appropriate tool) to PNK/BLU wire.
   
   2.) Connect the black multimeter test lead to the negative battery terminal.
   
   3.) Your multimeter should read 4.5 to 5 Volts DC.

2. 2

   Verify that the BLK wire has Ground with the key on but engine off.
   
   1.) Connect the black multimeter test lead (using the appropriate tool) to BLK wire.
   
   2.) Connect the red multimeter test lead to the battery positive (+) terminal.
   
   3.) Your multimeter should read 12 Volts DC.

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

CASE 1: The multimeter confirms you have power and Ground. This is good since you can rule out electrical wiring issues as behind the cause of the TPS trouble code lighting up the check engine light on your 1.6L Nissan Sentra.

You can conclude that the 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.

Therefore, you can conclude that the throttle position sensor is bad and needs to be replaced (and that this will solve the TP sensor code lighting up the check engine light).

CASE 2: Multimeter confirms that power or Ground are missing. Double check that you're testing the correct TP sensor harness terminal wire and repeat the test.

If your multimeter still doesn't show the indicated voltages, then we can conclude that there's an open in the wire 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 1.6L Nissan Sentra as being the cause of the problem and/or the TP sensor diagnostic trouble code (DTC) lighting up the check engine light (CEL).

More 1.6L Nissan Tutorials

You can find a complete list of tutorials in this index: Nissan 1.6L Index Of Articles.

Here's a small sample of the 1.6L Nissan tutorials you'll find in the index:

• How To Test Engine Compression (1.6L Nissan).
• How To Test For A Blown Head Gasket (1.6L Nissan).
• How To Test The Idle Switch (1997-1999 1.6L Nissan Sentra).
• Mass Air Flow (MAF) Sensor Test Nissan Sentra 1.6L (1995-1999) (at: easyautodiagnostics.com).