How To Test The MAP Sensor (1999-2006 V8 Silverado, Sierra, Suburban, Tahoe, Yukon)

The manifold absolute pressure (MAP) sensor, on the 1999-2006 V8 Chevrolet Silverado (Suburban, Tahoe) and GMC Sierra (Yukon, Yukon XL) can be easily tested with a simple multimeter.

In this tutorial, I'll explain how to do it in a step-by-step way. You'll be able to easily find out if it's bad (or not) in 3 simple tests.

You can find this tutorial in Spanish here: Cómo Probar El Sensor MAP (1999-2006 V8 Silverado, Sierra, Suburban, Tahoe, Yukon) (at: autotecnico-online.com).

NOTE: This tutorial applies to the following vehicles:

Chevrolet:

• Silverado (1500, 2500):
  • 4.8L, 5.3L: 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
• Silverado (2500):
  • 6.0L: 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
• Suburban (1500):
  • 5.3L: 2000, 2001, 2002, 2003, 2004, 2005, 2006
• Suburban (2500):
  • 6.0L: 2000, 2001, 2002, 2003, 2004, 2005, 2006
• Tahoe:
  • 4.8L, 5.3L: 2000, 2001, 2002, 2003, 2004, 2005, 2006

GMC:

• Sierra (1500, 2500):
  • 4.8L, 5.3L: 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
• Sierra (2500):
  • 6.0L: 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
• Yukon:
  • 4.8L, 5.3L: 2000, 2001, 2002, 2003, 2004, 2005, 2006
• Yukon XL (1500):
  • 5.3L: 2000, 2001, 2002, 2003, 2004, 2005, 2006
• Yukon XL (2500):
  • 6.0L: 2000, 2001, 2002, 2003, 2004, 2005, 2006

RELATED TROUBLE CODES:

• P0106 -What Does It Mean? (1999-2006 V8 Silverado, Sierra, Suburban, Tahoe, Yukon).
• P0107 -What Does It Mean? (1999-2006 V8 Silverado, Sierra, Suburban, Tahoe, Yukon).
• P0108 -What Does It Mean? (1999-2006 V8 Silverado, Sierra, Suburban, Tahoe, Yukon).

Symptoms Of A Bad MAP Sensor

A manifold absolute pressure (MAP) sensor problem will always cause the check engine light with one of the following trouble codes:

• P0106: MAP Sensor Performance Problem.
• P0107: MAP Sensor Voltage Too Low.
• P0108: MAP Sensor Voltage Too High.

You're also going to see one or more of the following symptoms:

• Won't pass the state mandated emissions test.
• Bad gas mileage.
• Lack of power, rough idle, or hesitation.
• Engine cranks a long time before starting.

MAP Sensor Circuit Descriptions

Below are the circuit descriptions of the 3 wires of the MAP sensor's connector.

Terminal	Wire	Description
A	Orange with black stripe (ORG/BLK)	Sensor Ground
B	Light green (LT GRN)	MAP Signal
C	Grey (GRY)	5 Volts

Where To Buy The MAP Sensor And Save

The MAP sensor, on the 1999-2006 V8 Chevrolet Silverado (Suburban, Tahoe) and GMC Sierra (Yukon, Yukon XL), is not an expensive engine management component.

The following links will help you to comparison shop and hopefully save you a few bucks on its purchase (AC-Delco is the original equipment manufacturer):

NOTE: The above manifold absolute pressure (MAP) sensor fits the following vehicles: 1999-2006 V8 Chevrolet Silverado (Suburban, Tahoe) and GMC Sierra (Yukon, Yukon XL).

TEST 1: Testing The MAP Voltage Signal

To get this show on the road, we're gonna' test the MAP voltage signal and see if it decreases/increases as you apply/release vacuum to the sensor.

If the MAP sensor is good, the MAP voltage signal should decrease when you apply vacuum to the sensor and increase when you release that vacuum.

If the MAP sensor is bad, you'll see that the MAP voltage signal will stay stuck in one value as you apply/release vacuum to the sensor.

IMPORTANT: The MAP sensor must remain connected to its electrical connector for this test to function properly. To be able to access the voltage inside the signal wire, you'll need to use either a back probe or a wire piercing probe. You can see an example of this tool here: Wire Piercing Probe.

Let's get started:

1. 1

   Remove the MAP sensor from the intake manifold. If you had to disconnect the MAP sensor from it's electrical connector to remove it, reconnect it now (the MAP sensor must remain connected to its connector for this test).

2. 2

   Connect the vacuum pump to the MAP sensor's vacuum inlet port.

3. 3

   Select Volts DC Mode on your multimeter.

4. 4

   Connect the red multimeter test lead to the middle wire of the MAP sensor's connector.
   
   In the photo above I've identified the middle wire with the number 2.
   
   NOTE: The MAP sensor must remain connected to its electrical connector to test the MAP signal voltage.

5. 5

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

6. 6

   Have your helper turn the key On but don't start the engine.

7. 7

   You should see a voltage around 4.5 Volts DC registering on your multimeter. If it doesn't, don't worry about it just yet, continue with the other steps.

8. 8

   Apply vacuum to the MAP sensor till the gauge's needle reaches 5 in. Hg of vacuum. These are the approximate readings you should see as you apply vacuum to the sensor:
   
   1.) 0 in. Hg ...... 3-4 Volts.
   
   2.) 5 in. Hg ...... 2.4 Volts.
   
   3.) 10 in. Hg .... 1.9 Volts.
   
   4.) 15 in. Hg .... 1.4 Volts.

9. 9

   Release the vacuum you've applied. The voltage reading should go back up to the value you registered in step 7.

Let's analyze your test results:

CASE 1: As you applied/released vacuum, the voltage decreased/increased. This is the correct test result and it tells you that the MAP sensor is OK.

Now, if the MAP sensor trouble code won't go away, take a look at the info found at: MAP Sensor Code Won't Go Away for a few more suggestions as to what could be causing the MAP sensor diagnostic trouble code (DTC).

CASE 2: As you applied/released vacuum, the voltage DID NOT decrease/increase. This test result usually confirms that the MAP sensor is bad and that it needs to be replaced.

But before you replace it, the next step is to make sure it's getting 5 Volts and Ground. Go to: TEST 2: Making Sure The MAP Sensor Is Getting 5 Volts.

CASE 3: The multimeter DID NOT register any voltage. This isn't good, but doesn't condemn the manifold absolute pressure (MAP) sensor as bad yet.

The next test is to make sure that the MAP sensor is getting 5 Volts. Go to: TEST 2: Making Sure The MAP Sensor Is Getting 5 Volts.