TPS TEST 2: Making Sure The TPS Is Getting Power
The throttle position sensor (TPS) on your 2.0L (SOHC & DOHC) vehicle needs power to work. This power comes in the form of 5 Volts DC from the fuel injection computer.
On the Dodge Neon, Plymouth Neon and Breeze, the wire that feeds the TPS with 5 Volts is the violet with white stripe (VIO/WHT) wire.
On the 1995-1999 2.0L DOHC Avenger, Talon, and Sebring, the wire that feeds the TPS with 5 Volts is the dark green with yellow stripe (DK GRN/YEL) wire.
Regardless of the color of the wire that feeds the TPS with 5 Volts, this wire connects to the female terminal labeled with the number 3 in the image above.
If the TPS is getting 5 Volts DC, then the next step is to make sure that it's getting Ground (in TEST 3).
These are the test steps:
- 1
Grab your multimeter and select Volts DC mode on it.
- 2
Probe the wire that connects to the female terminal labeled with the number 3 with the red multimeter test lead and an appropriate tool.
IMPORTANT: If you probe the front of the connector, be careful and do not damage the female terminal with your multimeter test lead. - 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 everything is set up, have a helper turn the key on but don't start the engine.
- 5
The multimeter should display 4.5 to 5 Volts on its screen.
OK, now let's interpret your test results:
CASE 1: The multimeter registered 4.5 to 5 Volts. This is the correct test result and confirms that the fuel injection computer and the circuit is supplying the TPS with power.
The next step is to test the Ground circuit of the throttle position sensor, go to: TEST 3: Making Sure The TPS Is Getting Ground.
CASE 2: The multimeter DID NOT register 4.5 to 5 Volts. This tells you that the computer or the wire are NOT providing the voltage that the TPS needs to operate.
The two most likely reasons for this are: 1) an open-circuit problem in the wire or 2) the fuel injection computer may be fried.
Altho' it's beyond the scope of this tutorial to test these two conditions, you have now eliminated the throttle position sensor (TPS) on your 2.0L (SOHC & DOHC) vehicle as being the cause of the problem and/or the TPS diagnostic trouble code (DTC) lighting up the check engine light (CEL).
TPS TEST 3: Making Sure The TPS Is Getting Ground
So far you have verified that the TPS is not creating a throttle position signal (TPS TEST 1) and that the TPS is getting power (TPS TEST 2). The second step, before condemning the throttle position sensor, is to verify that it also has a good Ground.
On the Dodge Neon, Plymouth Neon and Breeze, the wire that feeds the TPS with Ground is the black with light blue stripe (BLK/LT BLU) wire.
On the 1995-1999 2.0L DOHC Avenger, Talon, and Sebring, the wire that feeds the TPS with 5 Volts is the black with dark green stripe (BLK/DK GRN) wire.
Regardless of the color of the wire that feeds the TPS with Ground, this wire connects to the female terminal labeled with the number 1 in the image above.
NOTE: The fuel injection computer is the one that provides this Ground internally. Be careful and don't accidentally or intentionally apply power (12 Volts) to this circuit or you'll fry the fuel injection computer.
These are the test steps:
- 1
Place your multimeter in Volts DC mode.
- 2
Probe the wire that connects to the female terminal labeled with the number 1 with the black multimeter test lead.
IMPORTANT: If you probe the front of the connector, be careful not to damage the female terminal with the multimeter test lead. - 3
Now, with the red multimeter test lead, probe the battery positive (+) terminal.
- 4
Have your helper turn the Key to its ON position but don't start the engine.
- 5
Your multimeter will display 10 to 12 Volts, if Ground is present in the wire.
Let's interpret your test results:
CASE 1: The multimeter showed 10 to 12 Volts. This is the correct and expected test result. You can conclude that the TPS is getting Ground.
This multimeter test result also confirms that the TPS sensor is bad and needs to be replaced if you have:
- Confirmed that the TPS is not producing a TPS signal that increases/decreases as you open/close the throttle plate (TEST 1).
- Confirmed that it is getting 5 Volts and Ground (TEST 2 and TEST 3).
CASE 2: The multimeter confirms that Ground IS NOT present. This test result usually indicates a problem with either the fuel injection computer (internal fault/problem) or an open-circuit problem in the wire between the TPS and the computer itself.
Altho' testing these two conditions are beyond the scope of this article, you have now eliminated the throttle position sensor (TPS) on your 2.0L (SOHC & DOHC) vehicle as being the cause of the problem and/or the TPS diagnostic trouble code (DTC) lighting up the check engine light (CEL).
TPS Code Won't Go Away
So you've tested the throttle position sensor (TPS) and according to the test results, the TPS is good, but the check engine light keeps coming back on even after you erased the diagnostic trouble code (DTC) from the computer's (PCM) memory. Well, here are a couple of suggestions that might inspire your next diagnostic move:
- 1
The throttle plate's idle-stop screw's factory adjustment has been altered so that the engine could be idled up and mask a miss/misfire and/or rough idle. This increases the TP sensor's signal to the PCM. The PCM doesn't like it and lights up the check engine light (CEL).
- 2
The throttle cable is binding and causing the throttle plate to not fully close.
This can be verified by simply having someone inside the vehicle pushing the accelerator pedal to the floor and releasing it, with the engine OFF, while you visually check that the throttle plate and cable are not getting stuck somewhere in their travel. - 3
The TPS is failing intermittently. Which means that it works fine most of the time, but every now and then it doesn't:
I have found that the best way to test these intermittent problems is to road-test the vehicle with the multimeter hooked up to the TP signal wire with a long wire so that I can comfortably observe the signal going up and down as I or someone else drives. - 4
The TP sensor's connector is bad, usually the locking tab is broken and the connector has worked itself loose, causing an intermittent false connection.
If this info saved the day, buy me a beer!
