The throttle position sensor (TPS) can be tested using a simple multimeter and in this tutorial I'll show you how in a step-by-step way.

To test the TPS you don't need a scan tool (although having one is major plus).

The contents of this tutorial at a glance:

The throttle position sensor's job is to tell the PCM how much the throttle plate opens/closes as you step on/off the accelerator.

The PCM then uses this info to calculate fuel injection, advance/retard ignition timing, etc. So, when the TPS fails... your 4.7L Dodge engine is gonna' resent it.

Here are some of the symptoms your 4.7L Dodge will experience when the throttle position sensor fails:

  1. A TPS diagnostic trouble code (DTC) stored in the PCM's memory:
    1. P0121: Throttle Position (TP) Circuit Performance Problem.
    2. P0122: Throttle Position (TP) Circuit Low Input.
    3. P0123: Throttle Position (TP) Circuit High Input.
  2. Your 4.7L Dodge fails the smog check (state mandated emissions test).
  3. Bad gas mileage.
  4. Hard start and/or extended cranking time (after shut off).
  5. Black smoke coming out of the tailpipe.
  6. Hesitation when accelerating your vehicle down the road.

As mentioned at the beginning of this tutorial, the TPS can be tested without a scan tool and in the next section we'll start with the very first test.