The manifold absolute pressure (MAP) sensor can be easily tested with a multimeter and in this tutorial, I'll explain how you can do it in 3 test steps.
With your test results, you'll able to find out if it's bad or not. You'll also be able to diagnose the following trouble codes: P0106, P0107, P0108.
Contents of this tutorial:
You can find this tutorial in Spanish here: Cómo Probar El Sensor MAP (1995-1997 2.7L Honda Accord) (at: autotecnico-online.com).
APPLIES TO: This tutorial, on how to test the MAP sensor, applies to the following vehicles:
- 2.7L V6 Honda Accord: 1995, 1996, 1997.
RELATED TROUBLE CODES:
- P0106 -What Does It Mean? (1996-1997 2.7L Honda Accord).
- P0107 -What Does It Mean? (1996-1997 2.7L Honda Accord).
- P0108 -What Does It Mean? (1996-1997 2.7L Honda Accord).
Symptoms Of A Bad MAP Sensor
The fuel system on your 2.7L Honda Accord is a 'speed-density' system. In this type of fuel system, the fuel injection computer needs to know three things to be able to calculate the correct amount of air entering the engine.
These three things are:
- Intake air temperature.
- Engine RPM.
- Engine load.
Once the computer has figured out how much air is entering the engine, it can now calculate the correct amount of fuel to inject into the engine.
The sensor that informs the computer of engine load is the manifold absolute pressure (MAP) sensor.
Since the MAP sensor is such a critical component of the engine management system, when it fails, you're going to see the check engine light illuminated by one of the following trouble codes:
- P0106: MAP Sensor Range/Performance Problem.
- P0107: MAP Sensor Voltage Too Low.
- P0108: MAP Sensor Voltage Too High.
You're also gonna' see one or more of the following symptoms:
- Bad gas mileage.
- Black smoke coming out of the tail pipe, especially when you accelerate the vehicle.
- No power and/or hesitation as you accelerate the vehicle. It feels like all of a sudden someone cut the power momentarily as you step on the accelerator pedal.
Where To Buy The MAP Sensor And Save
The following links will help you to comparison shop for the MAP sensor and save a few bucks!:
If you're not sure if the above MAP sensor fits your particular 2.7L Honda Accord don't worry, once you get to the site, they'll make sure the sensor is the right one, if not, they'll find you the right one.
TEST 1: Checking The MAP Signal With A Multimeter
The first thing that we're gonna' do is to check the MAP sensor's signal voltage.
To be a bit more specific, we'll check that the voltage signal decreases as vacuum is applied to the sensor.
And as vacuum is released, we'll check that the voltage signal increases.
If the MAP signal voltage stays stuck in one value, as you apply/release vacuum to the MAP sensor, then you can conclude that it is bad and needs to be replaced.
NOTE: You'll need a multimeter to test your vehicle's MAP sensor. If you don't have one and need to buy one or upgrade yours, the following recommendation will help: Buying A Digital Multimeter For Automotive Diagnostic Testing.
IMPORTANT: The MAP sensor must remain connected to its electrical connector to read its voltage signal. You'll need to use a back-probe on the connector or a wire piercing probe on the wire to access the MAP signal. You can see an example of this tool here: Wire Piercing Probe Review.
OK, let's start:
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).
Connect the vacuum pump to the MAP sensor's vacuum inlet port.
Select Volts DC Mode on your multimeter.
Connect the red multimeter test lead to the white with yellow stripe (WHT/YEL) wire of the MAP sensor's connector.
In the photo above I've identified the WHT/YEL wire with the number 3.
NOTE: The MAP sensor must remain connected to its electrical connector to test the MAP signal voltage.
Ground the black multimeter test lead on the battery negative (-) terminal.
Have your helper turn the key On but don't start the engine.
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.
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.
Release the vacuum you've applied. The voltage reading should go back up to the value you registered in step 7.
Let's take a look at what your test results mean:
CASE 1: As you applied/released vacuum, the voltage decreased/increased. This is the correct test result and it lets you know that the MAP sensor is functioning correctly.
If the MAP sensor code won't go away, take a look at the info found at: MAP Code Will Not Go Away.
CASE 2: As you applied/released vacuum, the voltage DID NOT decrease/increase. This test result usually means that the MAP sensor is fried and that it needs to be replaced.
But we still need to make sure it's getting 5 Volts and Ground. For the next test 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.