TEST 2: Making Sure The TPS Is Getting 5 Volts
If you've reached this point, you've confirmed that the throttle position sensor is signal is not increasing/decreasing as you open/close the throttle plate.
In this test section, we're going to make sure that the sensor is getting 5 Volts. These 5 Volts are provided by the fuel injection computer.
The wire that delivers these 5 Volts to the sensor is the blue with red stripe (BLU/RED) wire of the TPS 4-wire connector.
The check for the presence of these 5 Volts, we'll do a simple multimeter voltage test on the female terminal that connects to the BLU/RED wire.
- 1
Disconnect the TP sensor from its 4-wire connector.
- 2
Turn the key to the ON position but don't crank or start the engine.
- 3
Place your multimeter in Volts DC mode.
- 4
Connect the black multimeter test lead to the battery negative (-) terminal.
- 5
With the red multimeter test lead, probe the female terminal of the connector that connects to the BLU/RED wire.
- 6
Your multimeter should read 4.5 to 5 Volts DC.
Let's take a look at what your test results mean:
CASE 1: 4.5 to 5 Volts are present. This is the correct and expected test result.
Your next step is to make sure the TPS is getting Ground. Go to: TEST 3: Making Sure The TPS Is Getting Ground.
CASE 2: 4.5 to 5 Volts ARE NOT present. Double check your connections and make sure that you're testing the correct terminal.
If your multimeter still does not show 4.5 to 5 Volts, you can conclude that there's an open-circuit issue in the wiring 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 2.0L Toyota Camry as being the cause of the problem and/or the TP sensor diagnostic trouble code (DTC) lighting up the check engine light (CEL).
TEST 3: Making Sure The TPS Is Getting Ground
So far, your tests have confirmed:
- The TPS voltage signal does not increase/decrease as you open/close the throttle plate (TEST 1).
- The TPS is getting power (TEST 2).
In this test section, we're going to make sure that the sensor is getting Ground (which is provided internally by the fuel injection computer).
The wire that delivers this Ground to the sensor is the brown (BRN) wire of the TPS 4-wire connector.
The check for the presence of Ground in the BRN, we'll do a simple multimeter voltage test on the female terminal that connects to the BRN wire.
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.
- 1
Disconnect the TP sensor from its 4-wire connector.
- 2
Turn the key to the ON position but don't crank or start the engine.
- 3
Place your multimeter in Volts DC mode.
- 4
Connect the red multimeter test lead to the battery positive (+) terminal.
- 5
With the black multimeter test lead, probe the female terminal of the connector that connects to the BRN wire.
- 6
Your multimeter should read 10 to 12 Volts DC.
Let's take a look at what your test results mean:
CASE 1: The multimeter registered 10 to 12 Volts. This is the correct and expected test result.
You can conclude that your 2.0L Toyota Camry's TPS is bad if you have confirmed that:
- The TP sensor IS NOT providing a varying voltage signal when manually opening/closing the throttle plate (TEST 1).
- The TP sensor is getting 5 Volts DC (TEST 2).
- The TP sensor is getting Ground (this test section).
You'll need to adjust the TPS assembly if you replace it. The following Toyota Camry tutorial explains the adjustment procedure: Adjusting The Throttle Position Sensor Assembly (this heading is found in the tutorial: TPS Idle Switch Multimeter Test (1987-1991 2.0L Toyota Camry)).
CASE 2: The multimeter register DID NOT 10 to 12 Volts. Double check your connections and make sure that you're testing the correct wires.
If your multimeter still does not show Ground, you can conclude that there's an open-circuit problem in the wiring 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 2.0L Toyota Camry as being the cause of the problem and/or the TP sensor diagnostic trouble code (DTC) lighting up the check engine light (CEL).
More 2.0L Toyota Camry Tutorials
You can find a complete list of 2.0L Toyota Camry tutorials and wiring diagrams in this index:
Here's a sample of the tutorials you'll find there:
- How To Test The TPS w/ Manual Transaxle (1987-1991 2.0L Toyota Camry).
- How To Test For A Blown Head Gasket (1987-1991 2.0L Toyota Camry).
- How To Test The Engine Compression (1987-1991 2.0L Toyota Camry).
- How To Test The MAF Sensor (1987-1991 2.0L Toyota Camry).
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