
If the check engine light, on your 3.8L V6 minivan is illuminated by a P0108 or a P0109 diagnostic trouble code, this is the tutorial that'll help you test the MAP sensor.
In this tutorial, I'll explain the three tests you need to do to find out if the MAP sensor is bad or not. All three are done with a multimeter.
This is a very accurate test that will let you know beyond a shadow of a doubt if the MAP sensor is bad or not.
Contents of this tutorial:
- Symptoms Of A Bad MAP Sensor.
- How The MAP Sensor Works.
- Should I Just Replace The MAP Sensor?
- Where To Buy The MAP Sensor And Save.
- TEST 1: Checking The MAP Signal With A Multimeter.
- TEST 2: Making Sure The MAP Sensor Is Getting 5 Volts.
- TEST 3: Making Sure The MAP Sensor Is Getting Ground.
- More 3.8L V6 Chrysler, Dodge, And Plymouth Minivan Diagnostic Tutorials.
You can find this tutorial in Spanish here: Como Probar El Sensor MAP (2001-2004 3.8L V6 Chrysler, Dodge Minivan) (at: autotecnico-online.com).
APPLIES TO: This tutorial, on how to test the MAP sensor, applies to the following vehicles:
- 3.8L V6 Chrysler Town & Country: 2001, 2002, 2003, 2004.
- 3.8L V6 Dodge Grand Caravan: 2001, 2002, 2003.
HOW THE MAP SENSOR WORKS:
RELATED MAP SENSOR TESTS:
- How To Test The MAP Sensor (1994-1995 3.8L V6 Chrysler, Dodge, And Plymouth Minivan).
- How To Test The MAP Sensor (1996-2000 3.8L V6 Chrysler, Dodge, And Plymouth Minivan).
- How To Test The MAP Sensor (2004-2007 3.8L V6 Chrysler And Dodge Minivan).
Symptoms Of A Bad MAP Sensor
The fuel injection computer, of your minivan, needs to know three things to be able to know how much air is entering the engine and to be able to inject the correct amount of fuel.
These three things are intake air temperature, engine RPM, and engine load.
And as you've guessed it, the sensor that provides the engine load information 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:
- 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 out momentarily as you step on the gas to get the vehicle moving.
If your minivan's PCM is setting either a P0107 or a P0108 and want a better understanding of what they really mean, check out these step-by-step breakdowns:
- P0107 MAP Sensor Code Explained (1996–2009 3.8L V6 Chrysler, Dodge, And Plymouth Minivan).
- P0108 MAP Sensor Code Explained (1996–2009 3.8L V6 Chrysler, Dodge, And Plymouth Minivan).
How The MAP Sensor Works
The MAP sensor (short for Manifold Absolute Pressure) plays a big role in how your 3.8L V6 minivan runs. Its main job is to track the vacuum inside the intake manifold —which tells the computer how much load the engine is under at any given moment.
Here's a simple breakdown of what the MAP sensor does once the engine is cranking and running:
- The PCM (Powertrain Control Module) sends the sensor a 5 Volt reference along with a Ground connection so it can operate.
- When the engine is idling, manifold vacuum is strong. The MAP sensor picks this up and sends back a low voltage signal —usually somewhere between 1.1 and 1.8 Volts.
- As soon as you press the accelerator and open the throttle, vacuum drops. The sensor reacts by increasing its signal voltage —often rising up to 4 Volts or more.
- This change tells the PCM the engine is working harder, so it adjusts things like fuel delivery and spark timing to match the demand.
- When you let off the gas and vacuum builds back up, the signal voltage drops again, and the PCM switches back to managing idle and cruising conditions.
Want to take a deeper look into how this sensor affects performance, fuel economy, and driveability?
Now that you've got a handle on how it works, you'll see that testing it isn't complicated at all —and we'll walk through it step by step.
Should I Just Replace The MAP Sensor?
When a P0107 or P0108 code pops up on your 2001–2004 3.8L V6 Chrysler, Dodge, or Plymouth minivan, it's natural to want a fast fix. Swapping the MAP sensor is a common first move, and in many cases, it really does solve problem and clears the code.
Even professional shops often go this route first. The sensor is easy to access, doesn't cost much, and can be replaced in just a few minutes. So if you're short on tools, pressed for time, or just want to try the quick solution —that's totally understandable.
If that sounds like your plan, here are two MAP sensors from well-known brands I trust and have personally used in my own repairs over the years:
- Walker Products 225-1040 MAP Sensor (Amazon affiliate link)
- Standard Motor Products AS158T MAP Sensor (Amazon affiliate link)
Buying through these Amazon links helps support this site and the tutorials I share —without costing you anything extra. Thanks a ton if you decide to use them!
But if you're more of a "test before replacing" kind of DIYer, this guide will walk you through the diagnostic process step by step. You'll just need a multimeter, a vacuum pump, and a few minutes to check things out properly.
Start with the basics right here: TEST 1: Checking The MAP Signal With A Multimeter.
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!:
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!
If you're not sure if the above MAP sensor fit your particular 3.8L V6 Chrysler (Dodge, Plymouth) minivan 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 very first thing that we're going to do is verify the MAP voltage signal that the sensor is producing.
To be a bit more specific, we're going to remove the MAP sensor from its place on the intake manifold and then connect it to a vacuum pump.
We're going to leave the MAP sensor connected to its electrical connector so that the fuel injection computer can power it up.
Then we'll apply vacuum to it and see if the MAP voltage signal decreases.
If the MAP voltage signal does not decrease, as vacuum is being applied to the sensor, then we can conclude that the MAP sensor is either defective or it's not getting power or Ground.
If you don't have a vacuum pump, no worries. You can use your mouth to apply a vacuum to the MAP sensor.
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:
- Tekpower TP8268 AC/DC Auto/Manual Range Digital Multimeter (Amazon affiliate link)
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:
- 1
Remove the MAP sensor from the intake manifold.
If unplugging the sensor was necessary to remove it, go ahead and plug it back in now —the sensor needs to stay connected during this test. - 2
Set your multimeter to Volts DC mode.
- 3
Touch the red test lead to the wire labeled violet with brown stripe (VIO/BRN) on the MAP sensor connector.
I've marked this wire as number 1 in the image above.
NOTE: Leave the MAP sensor plugged into its connector —you're measuring signal with the circuit live. - 4
Attach the black multimeter lead to the negative battery terminal.
- 5
Have your helper turn the key to the ON position (engine off).
- 6
Your meter should show around 4.5 Volts DC. If the reading is off, no need to stress yet —just keep going with the next steps.
- 7
Hook up your vacuum pump to the MAP sensor using a snug-fitting hose —I like to use a 3/8" fuel hose for this.
Whatever you use, make sure it seals tightly on both ends so you don't get a vacuum leak. - 8
Start applying vacuum with the pump. When the gauge hits 5 in. Hg, take a look at your voltage reading.
Here's what your readings should roughly look like at different vacuum levels:
1.) 0 in. Hg → ~4.7 Volts
2.) 5 in. Hg → ~3.9 Volts
3.) 10 in. Hg → ~3.0 Volts
4.) 15 in. Hg → ~1.1 Volts - 9
Release the vacuum. You should see the voltage rise back to what you got in step 6.
Here's how to make sense of your multimeter results:
CASE 1: The voltage dropped and rose as you applied and released vacuum. That's exactly what you want to see.
This result tells you the MAP sensor is functioning properly and doesn't need to be replaced. No additional MAP sensor tests are necessary.
If you've gone through the full testing process and the MAP-related code is still sticking around —it's starting to look like the sensor itself is not the issue at all. This related article digs into other common causes that can keep the PCM flagging a MAP code, even after replacing the sensor:
CASE 2: The voltage didn't change when vacuum was applied or released. This usually means the MAP sensor is bad —but we don't want to jump to conclusions just yet.
Before replacing the sensor, we need to verify it's actually getting the correct voltage from the PCM. Go to: TEST 2: Making Sure The MAP Sensor Is Getting 5 Volts.
CASE 3: No voltage reading at all from the MAP signal wire. That's not a great sign, but it doesn't automatically mean the MAP sensor itself is toast.
Let's confirm whether the sensor is even receiving its power supply. Continue to: TEST 2: Making Sure The MAP Sensor Is Getting 5 Volts.
TEST 2: Making Sure The MAP Sensor Is Getting 5 Volts

Like any other electrical component on your minivan, the MAP sensor needs power and Ground to function.
In this test section, we're going to make sure that the pink with yellow stripe (PNK/YEL) wire is providing the sensor with 5 Volts.
If 5 Volts are being supplied to the sensor, then we can move on to the next test, which is making sure that it's getting Ground.
In the photo above, I've labeled the PNK/YEL wire with the number 3.
IMPORTANT: On some of the 2001-2004 3.8L Chrysler/Dodge minivans, the wire that supplies 5 Volts to the MAP sensor is an orange with pink stripe (ORG/PNK) wire.
These are the test steps:
- 1
Place your multimeter in Volts DC mode.
- 2
Disconnect the MAP sensor from its electrical connector.
- 3
Gently probe the terminal that connects to the PNK/YEL with the red multimeter test lead.
NOTE: Be careful and don't damage the female terminal. I recommend using a back probe on the connector or a wire piercing probe on the wire. - 4
Connect the black multimeter test lead to the negative (-) battery terminal.
- 5
Have a helper turn the key on but don't start the engine.
- 6
The multimeter should display 4.5 to 5 Volts on its screen.
Let's examine your test result:
CASE 1: The multimeter registered 4.5 to 5 Volts. This is the correct test result.
Now that you have confirmed that the MAP sensor is getting power. The next step is to make sure that it is getting Ground. For this test go to: TEST 3: Making Sure The MAP Sensor Is Getting Ground.
CASE 2: The multimeter DID NOT register 4.5 to 5 Volts. Without these 5 Volts the manifold absolute pressure sensor will not function.
The two most likely reasons for this are:
- An open-circuit problem in the wire between the connector and the fuel injection computer.
- The fuel injection computer may be fried internally (very rare).
While testing those two conditions goes beyond what this tutorial covers, you've now ruled out the MAP sensor as the source of the issue on your 3.8L V6 Chrysler, Dodge, or Plymouth minivan. If the check engine light is still on and a MAP-related trouble code keeps coming back, you can be confident the sensor itself isn't to blame.
TEST 3: Making Sure The MAP Sensor Is Getting Ground

If you've reached this point, the test results of TEST 1 and TEST 2 have confirmed that:
- The MAP sensor is not producing a decreasing/increasing voltage as you applied/released vacuum to it.
- The MAP sensor is getting 5 Volts from the pink with yellow stripe (PNK/YEL) wire.
In this last test section, we're going to make sure that the dark blue with dark green (DK BLU/DK GRN) wire is providing the manifold absolute pressure sensor with Ground.
In the photo above, I have identified the DK BLU/DK GRN wire with the number 2.
IMPORTANT: If you probe the front of the female terminal, probe it very gently with your multimeter test leads. Or you run the risk of damaging the terminal.
CAUTION: The fuel injection computer provides Ground for the MAP sensor. Be careful and don't short the wire to battery 12 Volts or you'll fry the computer. The multimeter voltage test I'm suggesting is a safe way to test for Ground in this wire.
Let's get testing:
- 1
Place your multimeter in Volts DC mode.
- 2
Disconnect the MAP sensor from its electrical connector.
- 3
Gently probe the female terminal that connects to the wire labeled number 2 in the photo above with the black multimeter test lead.
This is the terminal that belongs to the dark blue with dark green (DK BLU/DK GRN) wire of the MAP sensor's 3-wire connector.
NOTE: Be careful and don't damage the female terminal. I recommend using a back probe on the connector or a wire piercing probe on the wire. - 4
Connect the red multimeter test lead to the battery positive (+) terminal.
- 5
Have your helper turn the key on but don't start the engine.
- 6
Your multimeter should display 10 to 12 Volts if Ground is present.
Let's see what this is pointing to:
CASE 1: Your multimeter showed 10 to 12 Volts. That's exactly what you want to see —it confirms the PCM is doing its job and the Ground circuit is functioning correctly.
This result also means you've got enough evidence to call the MAP sensor faulty, as long as these three things check out:
- The MAP sensor's signal voltage didn't respond when you applied vacuum (TEST 1).
- The PNK/YEL wire is feeding the sensor 5 Volts (TEST 2).
- The DK BLU/DK GRN wire is providing a solid Ground connection.
If you're ready to replace it, here are two MAP sensors I recommend —from brands I've personally used and had dependable results with in real-world repairs:
- Walker Products 225-1040 MAP Sensor (Amazon affiliate link)
- Standard Motor Products AS158T MAP Sensor (Amazon affiliate link)
Buying through these links helps support this site and keeps these free tutorials coming —at no extra cost to you. It's a small way to say thanks, and I truly appreciate it.
CASE 2: Your multimeter DID NOT show 10 to 12 Volts. This result points to one of two possible issues: either there's a break in the Ground wire between the sensor and the PCM, or there's an internal problem within the PCM itself.
While digging deeper into those two possibilities goes beyond what this tutorial covers, what you've done here is just as important —you've ruled out the MAP sensor as the cause of the issue or the reason the check engine light is flagging a MAP-related DTC.
More 3.8L V6 Chrysler, Dodge, And Plymouth Minivan Diagnostic Tutorials
If you're trying to get to the bottom of a check engine light or rough running issue on your 3.8L V6 Chrysler, Dodge, or Plymouth minivan, this article index is a great place to start. It's full of step-by-step guides:
Below is a small sample of what you'll find inside:
- How To Check For Vacuum Leaks: Carb Cleaner Spray (1994-2009 3.8L V6 Chrysler, Dodge, And Plymouth Minivan).
- Common Causes Of Spark Plug Failure (1994-2010 3.8L V6 Chrysler, Dodge, And Plymouth Minivan).
- How To Test A Blown Head Gasket (1994-2010 3.8L V6 Chrysler, Dodge, And Plymouth Minivan).
- How To Test Engine Compression (1994-2010 3.8L V6 Chrysler, Dodge, And Plymouth Minivan).

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