How To Test The TPS (1998-2003 2.2L Isuzu Amigo And Rodeo)

TEST 2: Making Sure The TPS Has 5 Volts

The wire that feeds the throttle position sensor with 5 Volts is the red (RED) wire of the TPS connector.

To check for the presence of these 5 Volts in the RED wire, we'll do a simple multimeter voltage test.

These are the test steps:

1. 1

   Place your multimeter in Volts DC mode.

2. 2

   Disconnect the TPS from its electrical connector.

3. 3

   Turn the key the ON position but don't start the engine.

4. 4

   Connect the red multimeter test lead (using the appropriate tool) to the RED wire.

5. 5

   Connect the black multimeter test lead to the negative (-) battery terminal.

6. 6

   Your multimeter should read 4.5 to 5 Volts DC.

Let's analyze your test results:

CASE 1: The RED wire is feeding the TPS with 5 Volts. This is the correct test result.

Now that you have confirmed that your 2.2L Isuzu Rodeo's TPS is getting 5 Volts, the next step is to make sure it's getting Ground. Go to: TEST 3: Making Sure The TPS Has Ground.

CASE 2: The RED wire IS NOT feeding the TPS with 5 Volts. Without these 5 Volts the TPS, on your 2.2L Isuzu Rodeo, will not function.

The most likely cause of these missing 5 Volts is an open-circuit problem in the RED wire between the TPS sensor's connector and the fuel injection computer's connector.

TEST 3: Making Sure The TPS Has Ground

For our last throttle position sensor test, we're gonna' make sure that the green (GRN) wire is providing Ground.

We'll confirm the presence of Ground in the GRN wire by doing a multimeter voltage test.

NOTE: Ground is provided by the fuel injection computer of your 2.2L Isuzu Rodeo. Be careful and don't connect this wire to battery 12 Volts or you'll fry the fuel injection computer. The multimeter voltage test I'm suggesting below is a safe way to test for the presence of Ground in the wire.

Let's get started:

1. 1

   Place your multimeter in Volts DC mode.

2. 2

   Disconnect the TPS from its electrical connector.

3. 3

   Turn the key the ON position but don't start the engine.

4. 4

   Connect the black multimeter test lead (using the appropriate tool) to the GRN wire.

5. 5

   Connect the red multimeter test lead to the positive (+) battery terminal.

6. 6

   Your multimeter should read 10 to 12 Volts DC.

Let's analyze your test results:

CASE 1: The GRN wire is feeding Ground to the TPS. This is the correct test result.

You can correctly conclude that the TPS is defective if you have:

• Confirmed that the TPS voltage signal does not increase/decrease as you opened/closed the throttle plate (TEST 1).
• Confirmed that the TPS is getting 5 Volts on the RED wire (TEST 2).
• Confirmed that the TPS is getting Ground on the GRN wire (this test).

Check my TPS recommendations here: Where To Buy The TPS And Save.

CASE 2: The GRN wire IS NOT feeding Ground to the TPS. Without Ground the TPS will not function.

The most likely cause of this missing Ground is an open-circuit problem in the GRN wire between the throttle position sensor's connector and the fuel injection computer's connector.