Throttle Body Temp Sensor Tests (1989-1991 5.2L, 5.9L V8 Dodge Ram Pickup)

TEST 2: Hot Temperature Resistance Check

OK, so now that you've checked the throttle body temp sensor cold during TEST 1, let's heat it up and see if its internal resistance changes.

At 200°F, the sensor should show an internal resistance of between 400 and 1,500 Ohms. To check it at that temp, we're gonna dunk it in hot, boiling water –which boils at 212°F.

At this temperature (of the boiling hot water), if it's internal resistance doesn't match the specification, we can conclude it's toast.

CAUTION: Boiling water can cause burns, so take these precautions:

• Never touch the sensor or wires with bare hands while it's hot.
• Don't submerge the electrical connector —only the metal sensing tip goes in the water.
• Keep the sensor connected to your multimeter with long jumper wires with insulated alligator clips to avoid putting your hands near the hot water. Need to buy some? —Jumper Wires With Insulated Alligator Clips (at: amazon.com).
• Don't try to test resistance while the sensor is plugged into the vehicle —this test is done off the truck.
• Allow the sensor to cool fully before handling it afterward.

OK, let's begin:

1. 1

   Connect your multimeter leads to the sensor's terminals.
   
   IMPORTANT: Use jumper wires with alligator clips to keep your hands away from the hot water or hot surfaces during the test.

2. 2

   Set your multimeter to its Ohms (Ω) setting.

3. 3

   Boil a small pot of water using a stove or hot plate.
   
   You can use a kitchen thermometer to confirm the water is around 200–212°F (93–100°C).

4. 4

   Lower only the metal tip of the sensor into the boiling water.
   
   CAUTION: Do not submerge the plastic housing or electrical terminals.
   
   IMPORTANT: Use tongs or suspend the sensor with a wire —never hold it by hand.

5. 5

   Watch the resistance reading on your multimeter.
   
   At this temperature, the sensor should show a resistance between 400 and 1500 Ohms.

6. 6

   Remove the sensor and allow it to cool completely before touching it or reinstalling it.

Let's interpret your results:

CASE 1: The resistance is 0 Ohms. This confirms the TB temp sensor is bad and needs to be replaced.

CASE 2: The multimeter displayed infinite Ohms (OL). This confirms the TB temp sensor is bad and needs to be replaced.

CASE 3: The resistance does NOT fall within the indicated range. This is telling you that the TB temp sensor is faulty and should be replaced.

CASE 4: The resistance is within the indicated range. This is the correct and expected test result.

If the throttle body temp sensor passed TEST 1, you can conclude that the sensor itself is OK. If the TB temp sensor code is still popping up, the issue may be in the wiring between the sensor's connector and the FI computer.

More 5.2L, 5.9L V8 Dodge Ram Pickup Tutorials

You can find a complete list of tutorials for the 5.2L/5.9L V8 Dodge Ram Pickup in this index:

• 5.2L, 5.9L V8 Dodge Ram Pickup Index Of Articles.

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

• How To Test The Fuel Pump (1992-2003 5.2L, 5.9L Dodge Ram Pickup).
• How To Test The TPS (1992-1996 5.2L, 5.9L V8 Dodge Ram Pickup).
• How To Test The MAP Sensor (1992-1996 5.2L, 5.9L V8 Dodge Ram Pickup).
• Troubleshooting A Blown Head Gasket (1989-2003 5.2L, 5.9L V8 Dodge Ram Pickup).