P0108 MAP Sensor Code Explained (1998-2007 3.0L V6 Honda Accord)

  • By: Abraham Torres-Arredondo
  • Created: 13 July 2025
  • Updated: 13 July 2025
  • Articl Id: 627
P0108 MAP Sensor Code Explained (2002, 2003, 2004, 2005, 2006, 2007 3.0L V6 Honda Accord)

In this guide, I'll break down what causes a P0108 MAP Sensor High Voltage code on a 3.0L V6 Honda Accord, what symptoms to watch for, and what kinds of problems —like a shorted wire or a failing sensor— could be behind it.

I'll also point you to step-by-step tutorials that show you how to test the MAP sensor using just a multimeter and a vacuum pump.

By the end, you'll have a clear understanding of what this code means and what your next steps should be troubleshoot and resolve it.

Contents of this tutorial:

APPLIES TO: This tutorial applies to the following vehicles:

  • 3.0L V6 Honda Accord: 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007.

MAP SENSOR MULTIMETER TESTS:

OTHER MAP SENSOR TROUBLE CODES EXPLAINED:

MAP SENSOR CODE WON'T GO AWAY:

What Does P0108 Really Mean?

If your 1998–2007 3.0L V6 Honda Accord is showing a P0108 code, your scan tool might give you one of these descriptions:

  • Generic OBD II Definition: P0108 –Manifold Absolute Pressure (MAP) Sensor Circuit High Input.
  • Honda Factory Definition: P0108 –MAP Sensor Voltage Too High.

So what's that actually telling you? It means the PCM is seeing a MAP sensor signal that's way too high —typically above 4.5 Volts— and it doesn't match what the engine is actually doing.

To really understand what this code is telling us about the MAP sensor signal failure, we need to keep a few key things in mind:

  • Your Accord uses a speed-density fuel system, so the PCM relies heavily on the MAP sensor to calculate engine load and deliver the correct amount of fuel.
  • That MAP voltage should constantly change based on how much work the engine is doing.

More specifically:

  • At idle —foot off the gas and vacuum high— the MAP voltage should stay low (1.0 to 1.5 Volts).
  • As you apply throttle, load increases and vacuum drops —the voltage should rise gradually and predictably (a max of 4.5 Volts).
    • NOTE: Engine "load" refers to any real-world driving conditions —like accelerating, passing, climbing hills, or cruising with the A/C blasting and a full car.

But when that voltage gets stuck at the high end —or spikes suddenly for no clear reason— the PCM sees it as a red flag and sets the P0108 MAP Sensor High Voltage code.

Knowing what the PCM is reacting to gives you a solid starting point. It's your first clue that something's off —and helps you decide where to begin testing the sensor and its wiring.

Next, I'll go over what kind of symptoms show up when the PCM thinks the engine is under heavy load all the time —even when it isn't.

Common Symptoms Of A Code P0108

As I mentioned in the last section, when your 3.0L V6 Honda Accord sets a P0108 MAP Sensor Voltage High code, the PCM is seeing a signal that makes it think the engine is under heavy load —even when you're just idling at a red light.

This high voltage MAP signal can lead to all sorts of drivability problems. Here's what you might notice:

  • Engine running rich —you'll smell raw fuel from the exhaust.
  • Hard to start or longer-than-usual crank time.
  • Rough or unstable idle.
  • Poor fuel economy —you'll notice the extra stops at the gas pump.
  • Weak throttle response or sluggish acceleration.
  • Check engine light is on (CEL).
  • Engine might stall randomly, especially at low speeds or idle.

In the next section, I'll break down what really causes a P0108 —so you can get to the bottom of it ASAP.

What Causes Code P0108?

Here are the most common reasons you'll see a P0108 code on a 1998–2007 3.0L V6 Honda Accord:

  • MAP sensor failure: Internally shorted sensor that's stuck outputting high voltage.
  • Signal wire shorted to the 5 Volt reference —or directly to battery voltage.
  • Wiring damage near the connector —it's common for the insulation of the wires (where they exit the connector) to crack and peel off, exposing the wires' copper strands which then short together.
  • Connector damage —it's possible for the connector to become damaged in a way that the metal terminals inside lose their separation, allowing them to touch each other and short out internally.
  • PCM fault: Rare, but still a possibility if everything else checks out.

NOTE: When we say the MAP signal wire is "shorted," we're talking about it making unwanted contact with another wire.

An example of this would be if the MAP signal and 5 Volt supply wires both have damaged insulation and their bare copper strands are making contact with each other. This "short" would force voltage into the signal line, keeping it stuck at 4.5 to 5 Volts, throwing off the MAP reading and confusing the PCM.

Now the big question —should you go ahead and replace the sensor, or take a few minutes to test it first and be sure? That's what I'll help you decide in the next section.

Should You Replace The MAP Sensor?

When your 1998–2007 3.0L V6 Honda Accord throws a P0108 MAP Sensor High Voltage code, it's easy to think, "Maybe I'll just replace the sensor and see what happens".

And let me tell you, that "diagnostic" approach works more often than you'd think. If the sensor is internally shorted and locked at a high voltage output, swapping it out can clear the issue right away.

And if it doesn't fix the problem —at least now you know it's time to dig deeper. Since the MAP sensor isn't too expensive (if you buy it online) or hard to reach, a lot of folks treat replacement as step one in the diagnostic process.

If you're leaning that way, no shame in it. Here are two MAP sensors I recommend for these Accords —they fit and are from solid automotive brands:

1998-1999 3.0L V6 Honda Accords:

2000-2002 3.0L V6 Honda Accord:

2003-2004 3.0L V6 Honda Accord:

2005-2007 3.0L V6 Honda Accord:

Buying through those links helps support this site and keeps tutorials like this one free —at no extra cost to you. Thanks for that!

That said, if you're the kind who likes to be sure before spending money, I recommend testing the sensor first. You just need a multimeter and a few minutes to check the signal voltage, 5 Volt feed, and Ground.

Whether the problem's in the wiring —like a shorted signal wire— or in the sensor itself, this test will point you in the right direction.

Ready to dig in? I've got a full, hands-on tutorial that walks you through every step:

More 3.0L V6 Honda Accord Diagnostic Tutorials

Trying to get to the bottom of an issue on your 3.0L V6 Honda Accord? This index pulls together all my hands-on tutorials in one place, so you can troubleshoot faster and fix it right the first time.

Here's a quick look at some of the step-by-step guides waiting for you in the index:

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