TEST 2: Verifying Throttle Position Sensor Has 5 Volts And Ground
If your 1.5L Honda Civic's TP sensor failed TEST 1, then the next step is to make sure it's getting power and Ground before concluding that it's fried. Why? Because if it's missing power (or ground), it won't produce an increasing/decreasing voltage signal.
These are the 2 wires that you'll be testing in this test section:
- The yellow with white stripe (YEL/WHT) wire. This is the one that supplies 5 Volts.
- The green with white stripe (GRN/WHT) wire. This is the one that supplies Ground.
IMPORTANT: Your Honda Civic's fuel injection computer is the one that feeds both power and Ground to the throttle position sensor (TPS). Be careful and don't short the Ground wire (circuit) to battery voltage or you'll fry it.
You can see this test step performed in this YouTube video here: How To Test The TPS (1997, 1998, 1999, 2000, 2001 2.0L Honda CR-V) (NOTE: Although this video applies to the 1997-2001 2.0L Honda CR-V, the test procedure itself is the same for the 1993-2005 1.6L Honda Civic).
OK, with your multimeter set to Volts DC this is what you need to do:
- 1
Verify that the YEL/WHT wire has voltage ( 4.5 to 5 Volts DC ) with the key on but engine off.
1.) Connect the red multimeter test lead (using the appropriate tool) to the YEL/WHT wire.
2.) Connect the black multimeter test lead to the negative (-) battery terminal.
3.) Your multimeter should read 4.5 to 5 Volts DC. - 2
Verify that the GRN/WHT wire has Ground with the key on but engine off.
1.) Connect the black multimeter test lead (using the appropriate tool) to the GRN/BLK wire.
2.) Connect the red multimeter test lead to the battery positive (+) terminal.
3.) Your multimeter should read 10 to 12 Volts DC.
Let's take a look at what your test results mean:
CASE 1: The multimeter confirms you have power and Ground. Great, this test results tells us that the TPS is getting both and thus you can rule out electrical wiring issues as behind the cause of the TPS trouble.
Now, you can confidently conclude that the TPS is bad only if:
- You have confirmed that the TPS voltage signal IS NOT increasing/decreasing while opening/closing the throttle plate (in TEST 1).
- You have confirmed that the TPS is getting power (5 Volts) and Ground.
CASE 2: Multimeter confirms that power or Ground are missing. Double check that you're testing the correct TP sensor harness terminal wire and repeat the test.
If your multimeter still doesn't show the indicated voltages then we can conclude that there's an open in the wire 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 1.5 Honda Civic as being the cause of the problem and/or the TP sensor diagnostic trouble code (DTC) lighting up the check engine light (CEL).
More 1.5L Honda Civic Tutorials
You can find a complete list of 1.5L Honda Civic tutorials in this index:
Here's a small sample of the tutorials you'll find in the index:
- How To Test The MAP Sensor (1992-1995 1.5L Honda Civic And Honda Civic Del Sol).
- How To Test The PGM-FI Main Relay (1992-1995 1.5L Honda Civic).
- How To Test Engine Compression (Honda 1.5L).
- How To Test The Fuel Pump In 2 Tests (1992-1995 1.5L Honda Civic And Honda Civic Del Sol).
- How To Test The Igniter, Ignition Coil Accord, Civic, CRV, and Odyssey (at easyautodiagnostics.com).
If this info saved the day, buy me a beer!
