With the help of this tutorial, you'll be able to accurately test the throttle position sensor (TPS) on your 3.3L equipped Chrysler/Dodge mini-van with a multimeter.
The test I'm gonna' show you is an on-car test of the TPS, so there's isn't any need to remove it to test it.
This tutorial will also help you diagnose any one of the following TPS diagnostic trouble codes that may be lighting up the check engine light on your mini-van:
- P0121: TPS Voltage Does Not Agree With MAP.
- P0122: Throttle Position Sensor Circuit Low Input.
- P0123: Throttle Position Sensor Circuit High Input.
Contents of this tutorial:
You can find this tutorial in Spanish here: Cómo Probar El Sensor TPS (2001-2007 3.3L Chrysler) (at: autotecnico-online.com).
Basics Of The Throttle Position Sensor (TPS)
The throttle position sensor's job is to measure the angle of the throttle plate as you step on (and step off) the accelerator pedal since the throttle plate is connected to the accelerator pedal via the accelerator cable.
Your 3.3L Chrysler mini-van's PCM receives this throttle angle info on the middle wire. The other two provide power and Ground (to the TPS).
In the table below, you'll find a short description of what each wire does:
| 3.3L Chrysler Mini-Van TP Sensor Circuits (2001, 2002, 2003, 2004, 2005, 2006, 2007) |
||
|---|---|---|
| Pin | Wire Color | Description |
| 1 | DK BLU/DK GRN | Ground |
| 2 | BRN/ORG | Throttle Plate Position Signal |
| 3 | PNK/YEL | 5 Volts |
Where To Buy The TPS And Save
Any of the auto parts stores in your neighborhood will have the throttle position sensor but you'll spend a whole lot more because they mark it up quite a bit.
My suggestion is to buy it online or at least comparison shop to get an idea of how much it costs and how much you can save.
The following links:
TEST 1: Checking The Throttle Position Sensor (TPS) Signal
As you're already aware, the TP sensor's job is to create an increasing voltage signal as the throttle plate opens.
Then, this same voltage signal decreases back to its closed throttle voltage value when the throttle plate closes.
This voltage signal is sent to your Chrysler mini-van's PCM on the BRN/ORG (brown/orange) wire of the sensor's engine wiring harness connector.
So, in this test section, you'll connect your multimeter to the throttle position sensor's middle wire and check to see if the signal is actually increasing/decreasing as you manually open/close the throttle plate.
If the TPS is bad, then the voltage output will stay stuck at one value.
IMPORTANT: This is an on car test of the sensor and the throttle position sensor must remain connected to its harness connector.
Here are the test steps:
- 1
Place your multimeter in Volts DC mode and connect the red test lead to the BRN/ORG wire of the TP sensor harness connector.
NOTE: The TP sensor connector needs to be connected to the TPS, so you'll need to either back-probe the connector or use a wire piercing probe to get to the signal inside the wire (to see what a wire piercing probe looks like: Wire Piercing Probe Tool). - 2
Ground the black multimeter test lead directly on the battery negative (-) post.
- 3
Manually rotate the throttle.
You'll get the best results by opening and closing the throttle directly on the throttle body instead of stepping on the accelerator pedal. - 4
The multimeter should show an increasing voltage as you (or your helper) open up the throttle.
You'll get the best results by opening and closing the throttle directly on the throttle body instead of stepping on the accelerator pedal. - 5
The multimeter should show a decreasing voltage as you begin to close the throttle.
- 6
Using a screwdriver's handle, gently tap the TP sensor as you open and close the throttle and observer the multimeter.
The purpose (of tapping the TP sensor with the screwdriver's handle) is to see if the TP sensor shows gap's 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.
OK, let's examine your test results:
CASE 1: The TP sensor signal's voltage increased and decreased smoothly and without gaps. This is the correct and expected TPS test result. This result tells you that the TPS is working correctly.
This test result also tells you that:
- Circuit #1 is providing Ground.
- Circuit #3 is providing power (5 Volts DC).
CASE 2: The TP sensor signal's voltage did not increase or decrease. In the majority of the cases this TPS result tells you that the sensor is bad. But not always.
To be sure that the TPS is truly fried, we need to do 2 more tests. These tests involve checking that the sensor is getting both power and Ground. For the first of these two tests, go to: TEST 2: Making Sure The TPS Is Getting Power.
CASE 3: The TP sensor signal's voltage showed gaps in its voltage output as you tapped the sensor with the screwdriver. If the gaps in the multimeter's voltage readings only showed up when you were tapping on the TPS (with the screwdriver's handle) then this test result tells you that the TPS is bad and needs to be replaced.
