Oxygen Sensor Heater Test -P0141 (1996-1997 2.5L Dodge Dakota)

TEST 2: Testing The Heater Element's Resistance

If you've reached this point, you've confirmed that the rear O2 sensor on your 1996-1997 2.5L Dodge Dakota is getting battery power and Ground.

In this test section, we're now gonna' check that the heater element's resistance is within specification. The heater element resistance specification is: 5 to 7 Ohms.

If the O2 sensor heater is not within specification, you can confidently conclude that the O2 sensor is defective and that replacing it will solve the P0141 trouble code lighting up the check engine light on your Dodge Dakota's instrument cluster.

NOTE: Perform this test with a completely cold engine. Specially because the heater element specification is with the rear O2 sensor at room temperature.

OK, let's get started:

1. 1

   Locate the round male terminals #1 and #2 of the O2 sensor connector itself (not the engine wiring harness O2 connector).

2. 2

   With your multimeter in Ohms mode, probe terminals 1 and 2 of the O2 sensor itself.
   
   Remember, the connector on the O2 sensor itself has female terminals.

3. 3

   If all is OK, you should see about 5 to 7 Ωs on your multimeter.
   
   If the heater element is fried, your multimeter will show an open (usually indicated by the letters OL) or a number over 10 K Ωs.

Let's examine your test results:

CASE 1: The rear O2 sensor's heater resistance is within spec. This is the correct and expected test result and confirms that your 2.5L Dodge Dakota's rear O2 sensor is not defective.

CASE 2: Your multimeter showed an open circuit (OL). This test result tells you that the O2 sensor's heater element is defective.

Since you have checked and confirmed that the O2 sensor is getting power and Ground and that its resistance IS NOT within specification, you can replace it with a new one.

Where To Buy The Oxygen Sensor And Save

The rear O2 sensor on your 2.5L Dodge Dakota is an inexpensive component. Since it never hurts to save a few bucks on anything, the following links will help you to comparison shop for it and hopefully save you a couple of dollars on its purchase:

NOTE: If you're not sure if the above downstream O2 sensor fits your particular Dodge Dakota Pick Up, don't worry, once you get to the site, they'll make sure the sensor fits, if not, they'll find you the correct one.