How To Test: P0107 OBD II Trouble Code (Honda 2.2L, 2.3L)

OBD II trouble code P0107 Manifold Absolute Pressure (MAP) Circuit Low Voltage usually points to a bad MAP sensor.

Although it stinks your Honda (or Acura) is registering this code, the cool thing is that troubleshooting a diagnostic trouble code P0107 is not that hard. In this tutorial I'll go over the basics you need to know to get to the bottom of the problem.

P0107 Basics You Need To Know

The manifold absolute pressure (MAP) sensor's job is to measure the amount of vacuum in the intake manifold. engine vacuum changes as engine load increases or decreases.

The bigger the engine load (think accelerating your Honda to pass someone on the highway), the more fuel needs to be injected into the engine.

The smaller the engine load (think coming to a stop light and the engine idling), the less fuel the engine needs. So, the info that the MAP sensor provides to the PCM is critical for smooth engine operation and performance.

You've probably already noticed that the MAP sensor has 3 wires in its connector. Each one has a specific job. Here's a brief description of the function of each:

1. One wire is the power source.
   • This power is in the form of 5 Volts DC.
   • The PCM (Powertrain Control Module = Fuel Injection Computer) provides these 5 Volts with the Key On Engine OFF (KOEO) or Key On Engine Running (KOER).
   • Provided by the wire that connects to the pin labeled with the number 1 in the image above.
2. One wire is a Ground wire.
   • In tech circles, this circuit is know as the low reference circuit.
   • The PCM provides this Ground internally.
   • Ground provided by the middle wire of the MAP sensor connector. This is the wire that connects to the pin labeled with the number 2 in the image above.
3. One wire is the MAP sensor signal circuit.
   • This wire sends the signal the MAP sensor creates to the computer.
   • MAP signal fed to the PCM by the wire that connects to the pin labeled with the number 3.
   • The higher the vacuum in the intake manifold, the smaller the voltage the MAP sensor outputs to the PCM. In other words, the MAP sensor produces a smaller voltage when more vacuum is applied to it.
   • The lower the vacuum in the intake manifold, the bigger the voltage the MAP sensor creates and sends to the PCM. In simple terms, the MAP sensor produces a higher voltage when less vacuum is applied to it.

When a P0107 Manifold Absolute Pressure (MAP) Circuit Low Voltage lights up the check engine light (CEL), on your 2.2L/2.3L equipped Honda, the PCM is letting you know that the MAP sensor's signal doesn't jive with actual engine operating conditions.

More specifically, that the MAP sensor is stuck reporting a low voltage because it can no longer sense when the engine IS NOT under load.

Symptoms Of A P0107 Diagnostic Trouble Code

Since the PCM depends on the MAP sensor for engine load info (to inject more or less fuel into the engine cylinders), when it fails you'll see one or several of the following symptoms:

1. Check engine light (CEL) is shining nice and bright on the instrument cluster.
2. DTC P0107 is present.
3. Rough idle.
4. ‘Rotten egg’ smell coming from the exhaust.
5. Won't pass the state mandated emmissions test.
6. Bad gas mileage.
7. Lack of power, rough idle, or hesitation.
8. Engine cranks a long time before starting.

Let's go to the next subheading and let's get testing!

How To Diagnose Trouble Code P0107 Manifold Absolute Pressure (MAP) Circuit Low Voltage

Testing and/or troubleshooting the MAP sensor on your 2.2L, 2.3L Honda isn't hard. This is a brief summary of the 4 tests in this tutorial:

1. Check the pressure value that the MAP sensor is reporting.
   • This can easily be done with a scan tool with Live Data capability.
   • Don't have a scan tool? Need a scan tool? check out my recommendation: Actron CP9580 Scan Tool Review.
   • TEST 1: Checking MAP Sensor Output.
2. Check that the MAP sensor is getting power.
   • We'll use a multimeter to make sure the MAP sensor is getting 5 Volts DC from the PCM. This is a very simple and easy test.
   • TEST 2: Verifying The MAP Sensor Has Power.
3. Verify that the MAP sensor has a good path to Ground.
   • We'll be using a multimeter to verify this Ground path.
   • TEST 3: Verifying The MAP Sensor Has Ground.
4. Manually apply and release vacuum to see if the MAP sensor responds to these changes in pressure.
   • You can either use a vacuum pump or the good ole’ lungs for this simple test.
   • TEST 4: Bench Testing The MAP Sensor.

I recommend that you start with TEST 1: Checking The Output Of MAP sensor, but you can modify the following tests to fit your particular diagnostic needs.

Where To Buy The MAP Sensor

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Buying my parts online has been one of the biggest money saving decisions I've ever made and I think you'll benefit from it too.

If you're wondering if this is the MAP sensor that'll fit your particular Honda, amazon.com will ask you for the specifics of your particular Honda or Acura vehicle to make sure it fits. If it doesn't, they'll show you several that will. It's that easy to find the right part!

Give it a try and see for yourself just how much you can save! I think you'll agree that buying it online is a whole cheaper and can be done without having to deal with the hassle of getting to the auto parts store.

TEST 1: Checking The MAP Sensor Output

To get our MAP sensor diagnostic on the way, the first thing we need to do is check the output of the MAP sensor, using a scan tool (with Live Data capability).

If the MAP sensor has failed; we'll be able to see the wrong pressure value it's reporting on the scan tool display.

This a very easy and simple test and I'll show you how to do it.

In case you don't have a scan tool with Live Data capability, check out my recommendation: Actron CP9580 Scan Tool Review

This is what you need to do:

1. 1

   Connect your scan tool to the OBD II connector and turn the key to the ON position.
   
   Once your scan tool powers on, go to its Live Data mode and scroll down to the MAP PID (Parameter Identification). See the image above.
   
   NOTE: Don't start the engine. This test is done with the Key On Engine Off (KOEO).

2. 2

   Take a look at what the MAP sensor PID is registering.
   
   What is your scan tool showing for the MAP sensor value?

3. 3

   The MAP PID should register 29 "HG (± 1 "HG) on your scan tool.
   
   NOTE: "HG stands for inches of mercury.

Let's take a look at what your test results mean:

CASE 1: The MAP sensor PID showed the indicated value. This tells you that the MAP sensor is OK at this time and that the problem is intermittent.

I'll explain: If the problem with the MAP sensor, and which is causing the P0107 Manifold Absolute Pressure (MAP) Circuit Low Voltage diagnostic trouble code (DTC), were present, you would have seen any other value but 29 "HG (± 1 "HG) on your scan tool.

If the P0107 DTC won't go away or keeps coming back, take a look at this subheading: MAP Sensor Is Good But Code Doesn't Go Away! for further testing tips/suggestions.

CASE 2: The MAP sensor PID DID NOT show the indicated value. This test result indicates a bad MAP sensor or a fault in the sensor's circuit. Why? Because with the Key On Engine Off (KOEO), the MAP sensor should only be measuring the ambient (outside) air pressure (known as barometric pressure).

Unless your car is parked on the summit of Mount Everest in the Himalayas, the pressure of the outside air is usually 29 "HG (± 1 "HG). So when the scan tool indicates a big deviation from this number, it's usually due to a bad MAP sensor.

The next step is go to: TEST 2: Verifying The MAP Sensor Has Power.