How To Test The MAP Sensor (1995-1996 1.5L Toyota Tercel)

TEST 2: Making Sure The MAP Sensor Is Getting 5 Volts

In this test section we're going to make sure that the MAP sensor, on your 1995-1996 1.5L Toyota Tercel, is getting 5 Volts from the fuel injection computer.

The wire that supplies 5 Volts to the MAP sensor is the light green with red stripe (LT GRN/RED) wire.

If 5 Volts are present in the LT GRN/RED wire, then the next step is to make sure that the MAP sensor is getting Ground (in TEST 3).

Let's examine your test results:

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 LT GRN/RED 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 examine your test results:

CASE 1: The LT GRN/RED wire is feeding the MAP sensor 5 Volts. This is the correct test result and tells you that the MAP sensor is getting power.

The next step is to make sure that the MAP sensor is getting Ground on the brown wire: TEST 3: Making Sure The MAP Sensor Is Getting Ground.

Let's examine your test results:

CASE 2: The LT GRN/RED wire IS NOT feeding 5 Volts to the MAP sensor. This test result usually tells you that there is an open circuit problem in the wire between the MAP sensor connector and the fuel injection computer's connector of your 1.5L Toyota Tercel.

Although it's beyond the scope of this tutorial to diagnose this lack of 5 Volts, your next step is to do a continuity test on the wire.

TEST 3: Making Sure The MAP Sensor Is Getting Ground

In this last text section, we're going to make sure that the brown (BRN) wire of the 3-wire MAP sensor connector is providing Ground to the MAP sensor.

In the photo above, the BRN wire is labeled with the number 3.

Testing for the presence of Ground in the BRN wire can easily be done by doing a simple multimeter voltage test on the wire.

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 BRN 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 examine your test results:

CASE 1: Ground is present on the BRN wire. This is the correct and expect the test result.

You can conclude that the MAP sensor, on your 1994-1995 1.5L Toyota Tercel is defective only if you have:

• Confirmed that the MAP voltage signal decreases/increases as you apply/release vacuum to the MAP sensor (TEST 1).
• Confirmed that the LT GRN/RED wire is feeding the MAP sensor with 5 Volts DC (TEST 2).
• In this test section, you've confirmed that the BRN wire is providing the MAP sensor with Ground.

CASE 2: The BRN wire IS NOT feeding Ground to the MAP sensor. This test result usually tells you that there is an open circuit problem in the wire between the MAP sensor connector and the fuel injection computer's connector of your 1.5L Toyota Tercel.

Although it's beyond the scope of this tutorial to diagnose this lack of Ground, your next step is to do a continuity test on the wire.

More 1.5L Toyota Tutorials

There are several more ‘how to’ tutorials that I've written that are 1.5L Toyota specific, that may be of further help. You can find the ones that are located here, at this site, by going to the Toyota 1.5L Index Of Articles.

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

• How To Test The Ignitor -Step By Step (1995-1996 1.5L Toyota Tercel).
• How To Test Engine Compression (1.5L Toyota Tercel).
• How To Test The Fuel Injectors (1995-1996 1.5L Toyota Tercel).
• How To Test For A Blown Head Gasket (1.5L Toyota Tercel).