How To Test The TPS (1998-2001 2.5L Ford Ranger)

TEST 2: Making Sure The TPS Is Getting 5 Volts

In this section, we're gonna' make sure that the throttle position sensor (TPS) on your 2.5L Ford Ranger (Mazda B2500) is getting power.

This power is in the form of 5 Volts DC and it's supplied to the TP sensor by your 2.5L Ford Ranger's fuel injection computer.

The wire that feeds this power to the TP sensor is the brown with white stripe wire of the TP sensor electrical connector.

We're gonna' do a simple multimeter voltage test to check for the presence of these 5 Volts with the Key On Engine Off.

NOTE: The locking tab of the TPS connector is a common failure point. There's a good chance that it's already broken or will break when you disconnect it. You can buy the TPS electrical connector here: Standard Motor Products S-867 Pigtail and Socket.

These are the test steps:

1. 1

   Place your multimeter in Volts DC mode.

2. 2

   Connect the red multimeter test lead to the brown with white stripe wire of the TP sensor connector.

3. 3

   Ground the black multimeter test lead on the battery negative (-) terminal.

4. 4

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

5. 5

   Your multimeter should read 4.5 to 5 Volts DC.

Let's interpret your test results:

CASE 1: 5 Volts are present in the BRN/WHT wire. This is the correct test result.

Now that we know that the TPS is getting power, the next step is to make sure that it's getting Ground. For this test go to: TEST 3: Making Sure The TPS Is Getting Ground.

CASE 2: 5 Volts ARE NOT present in the BRN/WHT wire. The TP sensor will not function if it's missing these 5 Volts.

The most common cause of this missing voltage is an open in the BRN/WHT wire between the TP sensor connector and the fuel injection computer's connector.

TEST 3: Making Sure The TPS Is Getting Ground

The fuel injection computer, of your 2.5L Ford Ranger (Mazda B2500), is the component that supplies the TP sensor with Ground.

This Ground is supplied to the TP sensor through the gray with red stripe (GRY/RED) wire of its 3-wire connector.

Finding out if this Ground is present simply involves doing a multimeter voltage test (just like the one we did to check for the 5 Volts on the BRN/WHT wire).

Let's get testing:

1. 1

   Place your multimeter in Volts DC mode.

2. 2

   Connect the black multimeter test lead to the GRY/RED wire of the TP sensor connector.

3. 3

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

4. 4

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

5. 5

   Your multimeter should read 10 to 12 Volts DC if Ground is present in the GRY/WHT wire.

Let's interpret your test results:

CASE 1: Ground is present in the GRY/WHT wire. This is the correct test result.

You can conclude that the throttle position sensor is defective if you have:

• Confirmed that the TP signal does not increase/decrease per the instructions in TEST 1.
• The TP sensor is getting power (TEST 2).
• The TP sensor is getting Ground.

CASE 2: Ground is NOT present in the GRY/WHT wire. The TP sensor will not function if it's missing this Ground.

The most common cause of this missing Ground is an open in the GRY/WHT wire between the TP sensor connector and the fuel injection computer's connector.

Broken TPS Connector

One of the most common problems you're going to encounter on your 2.5L Ford Ranger (Mazda B2500) with the throttle position sensor is a broken connector.

It doesn't matter how carefully you disconnect the throttle position sensor from its connector, the locking tab (on the connector) will break.

There's a good chance, that if the locking tab (on the TP connector) isn't broken on your Ford Ranger, you have already broken it by disconnecting it.

If the locking time is broken, you should replace it. The connector itself is not expensive and you can buy it here: Standard Motor Products S-867 Pigtail and Socket.

More 2.5L Ford Ranger Tutorials

You can find a complete list of tutorials here: Ford 2.5L Index Of Articles.

Here's a sample of the tutorials you'll find there:

• Ignition System Circuit Diagram (1998-2001 2.5L Ford Ranger).
• Oxygen Sensor Circuit Diagram (1998-2001 2.5L Ford Ranger).
• How To Test The Front O2 Sensor Heater (1998-2001 2.5L Ford Ranger).
• Rear O2 Sensor Heater Test (1998-2001 2.5L Ford Ranger).