How To Test The MAP Sensor (1993-1996 5.2L Grand Cherokee)

TEST 2: Making Sure The MAP Sensor Has 5 Volts

If you've reached this point, the MAP sensor is stuck producing a single voltage value as you applied/released vacuum to it in TEST 1.

In this test section, we're gonna' make sure that the MAP sensor is getting 5 Volts DC.

On the 1993-1995 5.2L V8 Jeep Grand Cherokee, the wire that supplies 5 Volts DC to the MAP sensor is the violet with white stripe (VIO/WHT) wire its connector.

On the 1996 5.2L V8 Jeep Grand Cherokee, the wire that supplies these 5 Volts is the white with black stripe (WHT/BLK) wire of the MAP sensor's connector.

This wire is identified with the number 1 in the photo above.

If the MAP sensor is getting 5 Volts, then the next step is to make sure it's getting Ground (in TEST 3).

Let's get testing:

1. 1

   Place your multimeter in Volts DC mode.

2. 2

   Disconnect the MAP sensor from its electrical connector.

3. 3

   Turn the key on but don't start the engine.

4. 4

   Connect the red multimeter test lead (using the appropriate tool) to the VIO/WHT (or WHT/BLK) wire.
   
   This is the wire labeled with the number 1 in the photo above.

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 multimeter confirms that 5 Volts are present. This is the correct test result.

Now that you have confirmed that your 5.2L Jeep Grand Cherokee's MAP sensor is getting 5 Volts, the next step is to make sure it's getting Ground. Go to: TEST 3: Making Sure The MAP Sensor Has Ground.

CASE 2: The multimeter confirms that 5 Volts ARE NOT present. Without these 5 Volts your 5.2L Jeep Grand Cherokee's MAP sensor will not function.

Although it's beyond the scope of this tutorial to troubleshoot these missing 5 Volts, the most likely cause is an open-circuit problem in the VIO/WHT wire between the MAP sensor's connector and the fuel injection computer's connector.

TEST 3: Making Sure The MAP Sensor Has Ground

Up to this point, your MAP sensor tests have confirmed that:

• The MAP sensor's voltage signal does not decrease/increase as you apply/release vacuum to it.
• The MAP sensor is getting 5 Volts on the VIO/WHT (or WHT/BLK) wire.

In this last test section, we're gonna' make sure that the black with light blue stripe (BLK/LT BLU) wire is providing Ground to your 5.2L V8 Jeep Grand Cherokee's MAP sensor.

In the photo above, the black with light blue stripe (BLK/LT BLU) wire is labeled with the number 3.

NOTE: Ground is provided by the fuel injection computer of your 5.2L V8 Jeep Grand Cherokee. So be careful and do not apply battery power (12 Volts DC) to the Ground wire or you'll fry the computer. The voltage test I'm describing below is a safe way of verifying the presence of this Ground.

These are the test steps:

1. 1

   Place your multimeter in Volts DC mode.

2. 2

   Disconnect the MAP sensor from its electrical connector.

3. 3

   Turn the key on but don't start the engine.

4. 4

   Connect the black multimeter test lead (using the appropriate tool) to the BLK/LT BLU 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: Ground is present in the BLK/LT BLU wire. This is the correct test result.

You can conclude that the MAP sensor is bad (and needs to be replaced) if you have:

• Confirmed that its MAP voltage signal does not decrease/increase as you apply/release vacuum to the MAP sensor (TEST 1).
• Confirmed that the MAP sensor is getting 5 Volts DC (TEST 2).
• Confirmed that the MAP sensor is getting Ground (this test).

Check my MAP sensor recommendations here: Where To Buy The MAP Sensor And Save.

CASE 2: Ground is not present. Without Ground the MAP sensor will not function.

Although it's beyond the scope of this tutorial to troubleshoot this missing Ground, the most likely cause is an open-circuit problem in the BLK/LT BLU wire between the MAP sensor's connector and the fuel injection computer's connector.