TEST 2: Verifying The TPS Has Power
If you've reached this test step, your Chrysler/Dodge vehicle's TPS did not pass TEST 1.
In this test section, we're gonna' make sure that the TPS is getting power. This power is in the form of 5 Volts and are supplied by the PCM.
The wire that feeds power to the TPS is the:
- 2.5L (H) engine: Violet with white stripe (VIO/WHT).
- 2.5L (N) engine: Green with yellow stripe (GRN/YEL).
The 5 Volt supply wire is identified with the number 1 in the photo above.
Here are the test steps:
- 1
Set your multimeter to Volts DC mode and turn the key on but don't crank or start the engine.
This will power up the TP sensor's connector. - 2
With the red multimeter test lead, probe the VIO/WHT (or GRN/YEL) wire of the TPS engine wiring harness connector.
IMPORTANT Do not probe the front of the TPS connector. Probing the metal terminal of the TPS connector could damage it and require that you replace the connector. Use a back probe or a wire piercing probe instead of probing the front of the connector. - 3
Connect the black multimeter test lead to a good and clean Ground point on the engine or directly on the negative (-) battery terminal.
- 4
When you've set up the test, have a helper turn the Key On Engine Off (KOEO).
- 5
Your multimeter should display 4.5 to 5 Volts on its screen.
Let's examine your test result:
CASE 1: The VIO/WHT (or GRN/YEL) wire has 5 Volts present. This is the correct test result.
Now that you've made sure the TPS is getting power, the next step is to make sure it's getting Ground. Go to: TEST 3: Verifying Throttle Position Sensor Has Ground.
CASE 2: The VIO/WHT (or GRN/YEL) wire DOES NOT have 5 Volts present. Without these 5 Volts the TPS will not function.
Several things can cause this problem. The three most common are:
- The MAP sensor is shorted internally (the MAP sensor shares the same 5 Volt circuit as the TPS).
- The A/C Pressure Transducer is shorted internally (the A/C Pressure Transducer shares the same 5 Volt circuit as the TPS).
- There's an open in the VIO/WHT wire between the TPS sensor connector and the PCM connector.
TEST 3: Verifying The TPS Has Ground
The wire that supplies Ground to the TPS is the:
- 2.5L (H) engine: Black with light blue stripe (BLK/LT BLU).
- 2.5L (N) engine: Black with green stripe (BLK/GRN).
The Ground wire is identified with the number 3 in the photo above.
To find out if the Ground is present in this wire, we're gonna' do a simple multimeter voltage test (like the one we did to find out if power was present on the 5 Volt wire).
IMPORTANT: This Ground is supplied by the PCM. Do not short this wire to Ground (accidentally or intentionally) or you're gonna' fry the PCM.
OK, let's find out if Ground is present:
- 1
Set your multimeter to Volts DC mode.
- 2
Probe the TPS connector's BLK/LT BLU (or BLK/GRN) wire with the black multimeter test lead.
IMPORTANT: Avoid probing the front of the TPS connector. Probing the metal terminal of the TPS connector could damage it and require that you replace the connector. Use a back probe or a wire piercing probe instead of probing the front of the connector. - 3
Now, with the red multimeter test lead, probe the battery positive (+) terminal.
- 4
Turn the key to its ON position but don't start the engine. This will power up the fuel injection computer.
- 5
Your multimeter will display 11 to 12 Volts if Ground is present in the wire.
Let's take a look at what your test results mean:
CASE 1: The BLK/LT BLU (or BLK/GRN) wire has Ground present. This is the correct test result.
If you've reached this point, you can conclude that the TPS is defective if you have:
- Confirmed that the TP signal is not increasing/decreasing as you open the throttle plate (TEST 1).
- Confirmed that the TPS is getting 5 Volts (TEST 2).
- Confirmed that the TPS is getting Ground (TEST 3).
CASE 2: The BLK/LT BLU (or BLK/GRN) wire DOES NOT have Ground present. Without Ground the TPS will not function.
The most common problem causing this lack of Ground is an open in the BLK/LT BLU (or BLK/GRN) wire between the TPS sensor connector and the PCM connector.
