MAP Sensor Code Won't Go Away (1998-2007 3.0L V6 Honda Accord)

  • By: Abraham Torres-Arredondo
  • Created: 13 July 2025
  • Updated: 13 July 2025
  • Articl Id: 654
MAP Sensor Code Won't Go Away (1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 3.0L V6 Honda Accord)

You've tested the MAP sensor. You've confirmed it works. Heck —maybe you even swapped in a brand-new one just to be sure. And yet… that check engine light keeps coming back with a P0107 or P0108 code. Frustrating, I know.

If the sensor's doing its job but the PCM still isn't happy, there's usually another issue behind the scenes. I've seen this happen a lot —and it almost always comes down to some problem outside the sensor itself.

This guide will walk you through the most common causes behind a persistent MAP sensor code, even after replacement. Whether the problem is electrical, vacuum-related, engine mechanical, or something sneakier, I'll help you track it down —and finally put that code to rest.

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:

MAP SENSOR TROUBLE CODES EXPLAINED:

Was The MAP Sensor Really the Problem?

You already swapped out the MAP sensor. Or maybe you ran through the tests —step-by-step— just like I showed you, and everything checked out fine. But the PCM keeps on nagging about the MAP sensor and triggering the check engine light. That P0107 or P0108 code just won't clear. And now you're wondering… did I miss something?

You're not the only one. I've been in that same spot —double-checking my tests, second-guessing what I thought I knew. Because in stubborn cases like this, the MAP sensor usually isn't the culprit— it's just the one getting blamed.

Something else is interfering with the signal or confusing the PCM —making it think the sensor is bad when it's really not.

In the next sections, I'll break down the most common things I've found that trigger this issue on these Accords —to see if one of those is the real cause of the MAP trouble code.

Wiring And Connector Problems That Trigger MAP Sensor Codes

Even when the MAP sensor itself is working just fine, a wiring problem can fool the PCM into thinking it's not. I've seen this plenty of times —especially on older Accords that have racked up the miles or even the occasional rat chewed-up engine wiring harness under the hood.

On the 1998–2007 3.0L Honda Accord, there are three critical wires tied to the MAP sensor: the signal wire, the 5 Volt reference wire, and the Ground wire.

Here's what you want to inspect:

  • Corrosion at the connector terminals: A little green or white buildup is all it takes to throw off the voltage and trigger false readings.
  • Wire broken right at the terminal crimp: The wires, right where they enter the plastic connector, may look fine from the outside —but inside, the copper strands could've snapped at the terminal. The wire looks OK on the outside because it's being held in place only by the insulation but the circuit is dead (since it's now open).
  • Cracked and peeling insulation: It's common on high-mileage engines. Where the wires enter the connector, the insulation can dry-rot and peel away (due to engine oil contamination), leading to shorts or erratic sensor signals.
  • Signal wire shorted to voltage: If the MAP signal wire gets shorted to power —internally or externally— it can spike the signal voltage and trick the PCM into flagging a high voltage fault like P0108.
  • Open circuit condition: If the 5 Volt feed or Ground wire has an open, the MAP sensor can't function —you'll get no signal, or one that's way off.

Any of these issues can cause the MAP signal to go haywire —even though the sensor itself is perfectly fine. So before replacing more parts, take a good look at the wiring. Inspect the connector closely and test all three circuits (power, Ground, and signal) with a multimeter to make sure they're solid.

If the visual check doesn't reveal anything obvious, go ahead and check continuity from the MAP sensor connector all the way to the PCM connector. And since you'll have the PCM unplugged anyway, it's a good time to check that none of those three wires are shorted together —a quick continuity check between them will tell you if the harness has any hidden internal damage.

Any one of these problems —even something minor— can mimic a bad MAP sensor and keep throwing that code.

Yes —Even New MAP Sensors Can Be Bad

One of the most frustrating things —especially when you've followed all the right steps— is replacing the MAP sensor and still getting the same trouble code or symptoms. You start questioning your diagnosis, second-guessing your test results, and wondering what you overlooked.

But here's something I've learned the hard way: brand-new sensors can be defective straight out of the box.

I've opened sealed packages, straight from the parts counter, only to install a sensor that didn't work at all. Others just gave me sketchy readings that took me awhile to diagnose and pin back to the new sensor.

And I get it, these parts are mass-produced by the thousands, and sometimes a bad one slips past quality control. It's rare, but when it happens, it's a hassle to deal with.

If you installed a new (or used) MAP sensor and nothing changed, don't rule out the possibility that you got a dud. It happens. And the only way to know for sure is to test the sensor you just installed. A few minutes with a multimeter and vacuum pump can save you hours of head-scratching.

If you haven't tested the sensor yet, check out the guide below. It'll walk you through the process and help you confirm whether that "new" part is actually good —or just good-looking.

Vacuum Leaks, Seal Problems, And Oil Contamination

The MAP sensor reads intake vacuum directly from the manifold (no vacuum hose inbetween delivering vacuum) —so anything that disrupts that vacuum signal can cause inaccurate readings and trigger codes like P0107 or P0108. And here's the catch: vacuum issues won't show up on a multimeter test. You've got to inspect them physically.

If you're still chasing a persistent MAP sensor code on your Accord, here are some often-overlooked things to check:

  • Damaged or missing O-Ring at the sensor base: The MAP sensor seals against the manifold using an O-Ring. Over time, that seal can harden, crack, or flatten out —letting in air and messing up the vacuum reading. If it looks worn or brittle, replace it.
  • Leaking intake manifold gaskets: It doesn't happen often, but it can —especially if the gaskets were recently replaced and weren't seated or torqued properly. Vacuum leaks from the gasket area can throw off MAP and oxygen sensor readings. To test this, you can use carb cleaner around the gasket area and listen for RPM changes.
  • Oil contamination inside the MAP sensor: On engines with blow-by, oil vapor can get pulled through the manifold and right into the sensor. That oil collects in the sensor's vacuum port and can coat the internal workings of the sensor —even if the sensor's electronics are still working. Pull the sensor and check for oil buildup inside or around the port.
  • Loose intake bolts (gaskets were recently replaced): If the intake manifold bolts weren't torqued properly, you can get vacuum leaks that cause MAP and oxygen sensor issues. Grab a torque wrench and give those bolts a check.

Engine Problems That Throw Off The MAP Sensor Signal

Sometimes, even when the MAP sensor and its wiring check out, internal engine issues can mess with vacuum and trick the PCM into thinking the sensor is bad. This is especially true on speed-density systems like the one used in your 1998–2007 3.0L V6 Honda Accord.

Here are a few examples that can throw the PCM off:

  • Low engine compression: If one or more cylinders have weak compression, overall intake vacuum drops. That lower vacuum can cause inaccurate MAP readings and set a MAP trouble code.
  • Valve timing that's off: A skipped timing belt tooth or cam-to-crank misalignment —maybe from a recent timing belt job— can throw off intake vacuum. Late valve timing is a classic vacuum killer and will confuse the PCM into thinking the MAP sensor is out of whack.
  • Exhaust restriction: A clogged catalytic converter or collapsed exhaust section can cause excessive backpressure. This reduces airflow and changes how vacuum behaves inside the manifold, often affecting the MAP signal in the process.

Issues like these can mimic a bad MAP sensor. If everything electrical checks out but the code keeps coming back, it might be time to run a compression test or take a closer look at valve timing and exhaust flow, especially if the car has high mileage or repair history.

Weak Fuel Pump Can Throw Off MAP Sensor Readings

A fuel pump that's on its way out —and can't keep up with fuel demand— will cause the engine to run lean, especially during acceleration or heavy load. While this usually sets fuel system codes like P0171 (System Too Lean Bank 1), it can also mess with the MAP sensor's output and lead to a false MAP trouble code.

Here's why: when the engine runs lean due to low fuel pressure, combustion becomes incomplete or unstable. That can reduce the engine's vacuum, particularly under load. The PCM monitors expected vacuum ranges through the MAP sensor —and if what it sees doesn't match what it expects, it may assume the MAP sensor is the problem.

If you're dealing with a persistent MAP code and haven't checked fuel pressure yet, now's a good time to grab a gauge and verify that the pump is delivering what it should.

Could The PCM Be At Fault?

It's not common —but it does happen. In some cases, the PCM itself is what's causing the MAP sensor code to keep coming back. I've seen it a few times over the years, and it's always one of the last things anyone expects.

Here's what usually goes wrong: a failure inside the PCM, especially in the circuit that supplies the 5 Volt reference or reads the MAP signal voltage, can trigger a P0107 or P0108 even when the sensor and wiring are perfectly fine.

The upside? Most PCM issues don't hide quietly. You'll often see other weird sensor readings or additional trouble codes pop up —particularly from sensors that share the same 5 Volt supply or Ground circuit as the MAP sensor.

Before you blame the PCM, though, make sure you've ruled out all of the following:

  • MAP sensor already tested or replaced: Confirm the sensor itself has been verified good.
  • All wires have good continuity: Test each MAP sensor wire from end to end between the connector and PCM.
  • No shorts between wires: Check that the MAP signal, power, and Ground wires aren't shorted together inside the harness.
  • Connector in good condition: Make sure the connector fits snug, has no terminal damage, and isn't corroded.
  • No voltage sag from other sensors: If another sensor that shares the 5V or Ground has shorted internally, it can pull the whole circuit down. Double-check all shared circuits.
  • PCM Grounds are solid: Test all PCM Grounds —do a voltage drop test if needed. A weak Ground can cause all kinds of strange issues.

Only after ruling all that out should you consider the PCM as a potential problem. If you're at that point, it's worth getting a second opinion from an experienced technician.

What really helps is coming in with your testing already done. If you can share solid test results, a good tech will be able to build on what you've found —and help you zero in on the next step.

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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