How To Test The MAP Sensor (1998-1999 3.0L V6 Honda Accord)

  • By: Abraham Torres-Arredondo
  • Created: 13 July 2025
  • Updated: 13 July 2025
  • Articl Id: 625
How To Test The MAP Sensor (1998, 1999 3.0L V6 Honda Accord)

In this tutorial, I'll walk you step-by-step through how to test the MAP sensor that's triggering a P0107 or P0108 code using just a multimeter and a handheld vacuum pump.

You'll learn how to check the MAP signal, verify the 5 Volt reference, and confirm the Ground —so you know for sure if the sensor is bad before replacing it.

This guide is written for DIYers and pros alike, with real-world tips and plain English explanations.

By the end, you'll know exactly how to troubleshoot MAP sensor problems and get your Accord running right again.

Contents of this tutorial:

APPLIES TO: This tutorial applies to the following vehicles:

  • 3.0L V6 Honda Accord: 1998, 1999.

RELATED MAP SENSOR TESTS:

Symptoms Of A Bad MAP Sensor

Your 3.0L V6 Honda Accord doesn't use a MAF (Mass Air Flow) sensor. Instead, it relies on a speed-density fuel injection system —and that system leans heavily on the MAP sensor. Along with engine RPM and intake air temperature, the MAP sensor helps the PCM figure out how much fuel to send into the cylinders.

So, when the MAP (Manifold Absolute Pressure) sensor starts feeding the wrong info to the PCM, engine performance can go sideways real quick. Fuel delivery gets thrown off, the air/fuel ratio takes a hit, and the engine just doesn't run right.

If the MAP sensor's on its way out —or has completely failed— you'll see the check engine light turn on, and it'll usually come with one of these two codes:

  • P0107 – MAP Sensor Circuit Low Voltage.
  • P0108 – MAP Sensor Circuit High Voltage.

If you're seeing either of those codes and want to dig a little deeper into what they mean, check out these step-by-step breakdowns:

Besides a MAP sensor diagnostic trouble code (DTC), you might notice:

  • Hesitation or stumbling when you hit the gas.
  • Rough idle or RPMs that bounce.
  • Worse gas mileage than usual.
  • Hard starts —engine cranks too long before firing up.
  • Black smoke from the tailpipe (usually from running too rich).
  • Low power —car feels bogged down or lazy.

Now, to be fair, these symptoms could point to other issues too —like low engine compression or weak fuel pressure. That's why you should always test the MAP sensor before swapping it out. Guessing can get expensive.

Next up, we'll talk about whether replacing the sensor right off the bat —or if taking a few minutes to test it is the way to go.

Should I Just Replace The MAP Sensor?

When a P0107 or P0108 code shows up on your 3.0L V6 Honda Accord, it's tempting to go straight for the fix and swap the MAP sensor. And you know what? A lot of folks do —even some repair shops— and many times, that takes care of the problem.

I've no issue with that approach. The MAP sensor's easy to get to, not too expensive, and a breeze to replace. If you're pressed for time, or you just don't have the tools, replacing it first isn't a bad move at all.

If that's the route you want to go, here are two replacement MAP sensors I recommend. They fit, work reliably, and come from known automotive brands I trust and use:

Buying through these links helps keep this site alive and free for everyone. It won't cost you anything extra —but it makes a big difference on my end. Thanks for your support!

Now, if you're the type who wants to be sure before replacing anything —I respect that too. And the good news? Testing the MAP sensor on your Honda is quick and easy. All you need is a digital multimeter and a handheld vacuum pump.

So, whether you're looking for peace of mind or just want to avoid guessing and wasting money, this first test section will get you started: TEST 1: Checking The MAP Sensor Signal.

Where To Buy The MAP Sensor And Save

You can find the MAP sensor just about in anywhere. The best place to buy it and save a few bucks is is online.

The following links will help you comparison shop for the MAP sensor:

Standard Motor Products AS64T MAP Sensor
Standard Motor Products AS64T MAP Sensor
Delphi PS10028 MAP Sensor19%
Delphi PS10028 MAP Sensor
$86.60

Disclosure: As an Amazon Associate, I earn from qualifying purchases. Buying through these links helps support this site at no extra cost to you. I truly appreciate it!

Not sure if the MAP sensor fits your particular vehicle? Don't worry, once you get to the site they'll make sure it fits by asking you the specifics of your particular vehicle. If it doesn't fit, they'll find you the right MAP sensor.

TEST 1: Checking The MAP Sensor Signal

Checking The MAP Sensor Signal. How To Test The MAP Sensor (1998, 1999 3.0L V6 Honda Accord)

What we're checking for in this first test section is simple: does the MAP sensor's output voltage signal respond the way it should when we apply and release vacuum to it?

If it doesn't —if the voltage just stays flat or jumps all over the place— the PCM is getting bad info. And that bad info is what's likely causing that P0107 or P0108 code to set and triggering the check engine light.

To test the MAP signal, we'll tap into the red with green stripe (RED/GRN) wire with a multimeter and apply vacuum with a handheld vacuum pump —that's it.

If you don't have these tools yet, here are a couple I recommend. The multimeter is one I've used myself many times, and the vacuum pump is a solid, affordable option that pairs well for this kind of test:

Using these links helps keep tutorials like this one free —and it won't cost you anything extra. I appreciate your support more than you know!

NOTE: If you don't have a vacuum pump, you can use your mouth to apply vacuum to the sensor via a clean vacuum hose.

There's one more tool you're gonna need, and that is either a back probe or a wire piercing probe to access the signal inside the RED/GRN wire. You can see what this tool looks like and where to buy it here: Wire Piercing Probe.

Alright, here's how to check the MAP signal output:

  1. 1

    Remove the MAP sensor from the intake manifold so you can get to its vacuum port.

  2. 2

    Attach your handheld vacuum pump to the MAP sensor's port using a short piece of hose.

    Make sure to leave the sensor plugged into its electrical connector while doing the test.

  3. 3

    Set your multimeter to DC Volts mode. The 20V setting is the sweet spot for this one.

  4. 4

    Ground the black multimeter lead.

    Easiest and best place? Connect it to the battery's negative (-) terminal.

  5. 5

    Now carefully probe the RED/GRN signal wire using your red multimeter lead.

    NOTE: You'll need to use a back-probe on the connector or a wire-piercing probe on the wire.

  6. 6

    Turn the key to the ON position, but don't crank the engine.

  7. 7

    Your multimeter should read somewhere between 3.8 to 4.5 Volts DC with zero vacuum applied.

  8. 8

    Now slowly apply vacuum using your hand pump or your mouth.

  9. 9

    Watch the voltage drop as vacuum builds. It should drop nice and smooth, landing somewhere around 1.1 Volts at full vacuum.

  10. 10

    Let go of the vacuum you just applied to the MAP sensor.

  11. 11

    You should see the voltage climb back up to where it started —right around that 3.8 to 4.5 Volt mark.

  12. 12

    Repeat the applying and releasing vacuum a few times.

    You want a smooth, steady change in voltage every time.

Alright, now let's make sense of the results you just saw:

CASE 1: Voltage dropped when vacuum was applied and came back up when released. Perfect —that's exactly how the MAP sensor should respond. It's doing its job, reacting to vacuum changes just like the PCM expects it to.

If you're still seeing a P0107 or P0108 code even though the sensor passed the test, chances are the problem lies somewhere else. This guide will help you track it down:

CASE 2: Voltage didn't move at all —no matter how much vacuum you added or released, the number on the multimeter just sat there. That usually means the MAP sensor is shot.

Still, before replacing it, let's make sure it's not a power issue. Head over to this next test: TEST 2: Making Sure The MAP Sensor Is Getting Power.

CASE 3: Multimeter showed 0 Volts from the signal wire. Now we're looking at one of two things —either the sensor is completely dead, or it's not even getting power or Ground in the first place.

The next step is to test the 5 Volt reference and the Ground circuit. Start here: TEST 2: Making Sure The MAP Sensor Is Getting Power.

TEST 2: Making Sure The MAP Sensor Is Getting Power

Making Sure The MAP Sensor Is Getting Power. How To Test The MAP Sensor (1998, 1999 3.0L V6 Honda Accord)

If the MAP sensor didn't react the way it should've in TEST 1, there's a real chance it's simply not getting the power or Ground it needs to do its job.

The MAP sensor runs on a steady 5 Volt reference signal supplied by the PCM. Without that power, it can't send a proper signal —even if the sensor itself is fine.

On your 1998–1999 3.0L V6 Honda Accord, this 5 Volt feed comes through the yellow with red stripe (YEL/RED) wire at the sensor connector.

Here's how to check that voltage with your multimeter:

  1. 1

    Unplug the MAP sensor from its connector so you can access the terminals.

  2. 2

    Switch your multimeter to measure DC Volts. Set it to the 20V range.

  3. 3

    Turn the key to the ON position, but don't start the engine.

  4. 4

    Connect the black multimeter lead to Ground —the battery's negative (-) terminal is the best spot.

  5. 5

    Gently probe the front of the YEL/RED female terminal using the red multimeter lead.

  6. 6

    You should see somewhere between 4.5 and 5.0 Volts on the screen.

Here's how to read those results:

CASE 1: You're reading 4.5 to 5 Volts at the YEL/RED wire. That's exactly what we want. The PCM is sending out the proper reference voltage.

Your next step is to confirm the sensor is also getting Ground. On this Honda, that comes through the green with white stripe (GRN/WHT) wire. Go to: TEST 3: Making Sure The MAP Sensor Is Getting Ground.

CASE 2: No voltage at the YEL/RED wire? Double-check your multimeter setup. If you're still reading zero, then the problem is upstream —the 5 Volt feed isn't making it to the sensor. That could mean a break in the wire, a short, or even an issue inside the PCM itself.

And if that's the case, replacing the MAP sensor won't help —it's not the sensor's fault. You'll need to trace the 5 Volt supply wire from the PCM to the sensor connector and check for continuity.

Once you've restored this 5V supply to the circuit, the MAP sensor will start working again.

TEST 3: Making Sure The MAP Sensor Is Getting Ground

Making Sure The MAP Sensor Is Getting Ground. How To Test The MAP Sensor (1998, 1999 3.0L V6 Honda Accord)

Now that you've confirmed the MAP sensor is getting its 5 Volt reference, there's one last piece to check —Ground. Without a solid Ground, the sensor can't complete the circuit. And if the circuit's incomplete, the PCM won't get a signal. Simple as that.

On your 1998–1999 3.0L V6 Honda Accord, Ground comes in through the green with white stripe (GRN/WHT) wire at the MAP sensor connector.

CAUTION: Since this is a PCM-supplied Ground, never connect this wire up to direct battery voltage —you'll deep-fry the PCM. The test below will let you check it safely using just a multimeter.

Here's how to test the Ground step by step:

  1. 1

    Leave the MAP sensor unplugged.

  2. 2

    Set your multimeter to Volts DC mode.

  3. 3

    Turn the key to the ON position, but don't start the engine.

  4. 4

    Connect the red multimeter lead to the battery's positive terminal.

  5. 5

    Gently probe the front of the GRN/WHT female terminal using the black multimeter lead.

  6. 6

    You should see a voltage reading between 10 to 12 Volts on the multimeter screen.

Now let's interpret what that result means:

CASE 1: Your multimeter read 10 to 12 Volts. That's great —the Ground circuit is solid, and the PCM is doing its job.

At this point, you've confirmed all three things the MAP sensor needs to function:

  • TEST 1: It didn't respond to vacuum —so the signal's no good.
  • TEST 2: It's getting the correct 5 Volt supply.
  • TEST 3: It's got a clean and working Ground.

Put it all together, and the MAP sensor itself is toast. It's internally bad —time to replace it.

Here are two MAP sensors I recommend for your Accord. These are from brands I trust, fit right, and hold up well:

These are affiliate links that help support the site without costing you anything extra. Thanks for that, by the way!

CASE 2: You didn't get a voltage reading. That tells us the Ground isn't making it to the sensor. It's an open-circuit somewhere along the way.

First, double-check your connections and test setup. Still nothing? Then it's time to troubleshoot that Ground wire between the MAP connector and the PCM. Restoring Ground to the circuit will get the MAP sensor working again.

More 3.0L V6 Honda Accord Diagnostic Tutorials

Whether you're chasing down a check engine light or just want to understand your Accord a little better, this index is a great place to start. It's full of real-world how-to guides written with both DIYers and experienced techs in mind.

Here's a quick peek at some of the step-by-step tutorials you'll find there:

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