If your 3.8L V6 Chrysler or Dodge minivan is showing a check engine light with code P0107 or P0108, this tutorial will walk you through how to test the MAP sensor step by step.
Using just a multimeter and a vacuum pump, you'll check the MAP sensor signal, confirm it's getting power and Ground, and figure out if it's truly the problem.
No scan tool or expensive diagnostic equipment needed —just basic tools and a few minutes of your time.
By the end of this guide, you'll know exactly what's going on and whether the MAP sensor is to blame for that P0107 or P0108 code.
Contents of this tutorial:
- Symptoms Of A Bad MAP Sensor.
- Should I Just Replace The MAP Sensor?
- Where To Buy The MAP Sensor And Save.
- TEST 1: Checking The MAP Sensor Signal.
- TEST 2: Verifying The MAP Sensor Is Getting Power.
- TEST 3: Making Sure The MAP Sensor Is Getting Ground.
- More 3.8L V6 Chrysler And Dodge Minivan Diagnostic Tutorials.
APPLIES TO: This tutorial applies to the following Dodge Ram pickups:
- 3.8L V6 Chrysler Town & Country: 2004, 2005, 2006, 2007, early 2008.
- 3.8L V6 Dodge Grand Caravan: 2004, 2005, 2006, 2007, early 2008.
OTHER MAP SENSOR TESTS:
- How To Test The MAP Sensor (1994-1995 3.8L V6 Dodge And Plymouth Minivan).
- How To Test The MAP Sensor (1996-2000 3.8L V6 Chrysler, Dodge, Plymouth Mini-Van).
- How To Test The MAP Sensor (2001-2004 3.8L V6 Chrysler, Dodge Mini-Van).
Symptoms Of A Bad MAP Sensor
Your minivan's 3.8L V6 engine doesn't use a MAF sensor like some vehicles do. Instead, it relies on a speed-density system, where the PCM calculates fuel delivery using inputs from the MAP sensor, engine RPM, and intake air temperature.
Since the MAP sensor plays a key role in keeping the engine's air-fuel mixture right, when it fails and starts feeding the PCM bad data, engine performance takes a hit.
One of the first signs you'll see, when the MAP sensor fails, is the check engine light with one of these two codes stored in the PCM's memory:
- P0107 –MAP Sensor Circuit Low Voltage.
- P0108 –MAP Sensor Circuit High Voltage.
If you're seeing either of those codes 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).
Besides a MAP sensor diagnostic trouble code (DTC), here are a few other symptoms you might run into when the MAP sensor starts sending the wrong signal to the PCM:
- Engine stumbles or hesitates when accelerating.
- Idle feels rough or inconsistent, especially at a stop.
- Bad gas mileage —you're stopping at the pump more often.
- Hard to start, or long cranking before it fires up.
- Rich-running conditions —black smoke from the tailpipe.
- Low power or sluggish throttle response.
Now, a bad MAP sensor isn't the only thing that can cause these symptoms. You could also be dealing with a vacuum leak, a wiring fault, or even fuel delivery issues. That's why testing it is important.
In the next section, we'll talk about whether you should just replace the sensor —or take the time to test it first.
Should I Just Replace The MAP Sensor?
When a P0107 or P0108 code shows up on your 2004–2008 3.8L V6 Chrysler or Dodge minivan, the instinct is to just swap out the MAP sensor. And honestly, that works more often than not —it usually solves the issue.
The MAP sensor is very accessible, doesn't cost much, and takes less than five minutes to replace, so replacing it right away makes sense.
If that's the route you're thinking of taking, here are two MAP sensors from brands I trust and have used with solid results over the years:
- Standard Motor Products AS217 MAP/BAPP Sensor (Amazon affiliate link).
- Delphi PS10229 MAP Sensor (Amazon affiliate link).
Buying through these links helps support the site and keeps tutorials like this one available to DIYers —and it won't cost you anything extra. I appreciate it more than you know!
Now, if you're the type who likes to verify things before replacing parts —you've come to the right place. Testing the MAP sensor only takes a few minutes, and all you need is a basic multimeter and a hand-held vacuum pump.
This section will walk you through the first step in diagnosing the MAP sensor: 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:
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 GM vehicle. If it doesn't fit, they'll find you the right MAP sensor.
TEST 1: Checking The MAP Sensor Signal
If you've got a P0107 or P0108 code showing up, the first thing to check is the MAP sensor's signal wire —specifically the violet with brown stripe (VIO/BRN) wire. That's the one that feeds pressure info straight to the PCM.
More specifically, we're gonna see if the sensor reacts the way it should when vacuum changes —vacuum that we'll manually apply— or if it's stuck sending a bogus signal that's throwing off the air/fuel mixture and triggering codes.
Like I mentioned earlier, all you need is a standard multimeter and a hand-operated vacuum pump. I'll walk you through how to use both step by step so you can read the signal voltage like a pro.
If you need a multimeter or vacuum pump, here's what I've personally used and trust to get the job done:
- Tekpower TP8268 AC/DC Auto/Manual Range Digital Multimeter (Amazon affiliate link).
- HTOMT 2 In 1 Vacuum Pump Test Set (Amazon affiliate link).
Buying through these links helps keep these tutorials free and DIY-focused —and doesn't cost you anything extra. Really appreciate the support!
NOTE: The vacuum port on the MAP sensor is usually too wide for the small hose that comes with most vacuum pumps. I use a spark plug boot from an old ignition wire to bridge the gap —fits tight and seals perfectly. You can use anything similar that helps adapt the hose size and holds vacuum.
IMPORTANT: The MAP sensor must remain connected to its 3-wire connector during this signal test. You can either use a back-probe on the connector or a wire piercing probe on the wire. You can see an example of this tool (and where to buy it) here: Wire Piercing Probe.
Here's how to run this test step by step:
- 1
Remove the MAP sensor from the intake so you can access the vacuum port on the sensor itself.
- 2
Attach a handheld vacuum pump to the sensor's vacuum port using a short piece of hose.
Leave the electrical connector plugged in during the entire test —that part stays connected. - 3
Set your multimeter to measure DC Volts. If it's got a 20V range, use that.
- 4
Connect the black multimeter lead to a solid Ground.
The negative (-) battery post is your best bet. - 5
Back-probe the VIO/BRN wire at the MAP sensor connector with the red multimeter lead.
You can also use a wire piercing probe on the VIO/BRN wire. - 6
Turn the key to the ON position, but don't start the engine.
- 7
You should see about 3.8 to 4.0 Volts DC with zero vacuum applied —that's your baseline reading.
- 8
Use the hand pump to slowly apply vacuum to the sensor.
- 9
Watch the voltage as vacuum increases. It should drop smoothly to around 1.1 Volts at full vacuum.
- 10
Let go of the vacuum pump and bring the pressure back to zero.
- 11
The voltage should rise back up to where it started —about 3.8 to 4.0 Volts.
- 12
Repeat the vacuum cycle a few times. You want a smooth and repeatable voltage drop and return every time.
Let's go over what your multimeter readings actually tell you:
CASE 1: Voltage dropped with vacuum and rose back up when released. That's the result you want. It means the MAP sensor is doing its job —reacting properly to pressure changes and feeding accurate info to the PCM.
If you're still seeing a P0107 or P0108 even though the sensor tested good, there's probably something else going on in the circuit. This guide will help you figure out what to check next:
CASE 2: Voltage stayed the same the whole time —no change no matter how much vacuum you applied.
Most of the time, this means the sensor has failed internally and is stuck sending bad data to the PCM.
But before you grab a new one, let's make sure it's actually getting the power it needs. Head to: TEST 2: Verifying The MAP Sensor Is Getting Power.
CASE 3: You're reading 0 Volts on the signal wire. That usually points to one of two things —either the sensor is completely dead, or it's not receiving 5 Volts (power supply) or a proper Ground.
The only way to know for sure is to check both power and Ground. Your next step is here: TEST 2: Making Sure The MAP Sensor Is Getting Power.
TEST 2: Verifying The MAP Sensor Is Getting Power
If your MAP sensor didn't respond correctly during TEST 1 —it could just be missing the power or Ground it needs to work. So before replacing it, let's confirm it's actually being supplied with voltage.
The MAP sensor depends on a clean 5 Volt reference signal from the PCM to operate. Without that voltage, it won't produce the right signal —no matter how much vacuum you apply.
On your 2004–2008 3.8L V6 Chrysler or Dodge minivan, this power is delivered through the pink with yellow stripe (PNK/YEL) wire at the sensor connector.
Here's how to check for that voltage using a digital multimeter:
- 1
Disconnect the MAP sensor so you can access the terminals inside the connector.
- 2
Set your multimeter to read DC Volts.
- 3
Turn the ignition to the ON position, but don't crank the engine.
- 4
Connect the black multimeter lead to the battery's negative (-) terminal.
- 5
Carefully probe the female terminal that corresponds to the PNK/YEL wire using your red multimeter lead.
NOTE: Gently probe the front of the terminal to avoid damaging it. - 6
Your reading should fall between 4.5 and 5.0 Volts.
Here's how to interpret your result:
CASE 1: You've got 5 Volts at the PNK/YEL wire. Perfect —that means the PCM is supplying the reference voltage correctly.
Next up, let's make sure the sensor is also receiving a solid Ground through the dark blue with dark green stripe (DK BLU/DK GRN) wire. Continue to: TEST 3: Making Sure The MAP Sensor Is Getting Ground.
CASE 2: No voltage at the PNK/YEL wire. First, double-check your multimeter connections and settings and repeat the test.
If you're still seeing 0 Volts, there's a problem in the 5 Volt reference circuit —could be a broken wire, a short to Ground, or an issue inside the PCM.
In that case, the MAP sensor isn't the culprit. Swapping it out won't fix anything. You'll need to check continuity on the PNK/YEL wire back to the PCM to find where the fault lies.
TEST 3: Making Sure The MAP Sensor Is Getting Ground
Now that you've confirmed the MAP sensor is getting its 5 Volt power, the last piece of the puzzle is verifying that it also has a good Ground. Without Ground, the circuit can't complete —and that means no output signal to the PCM.
On your 2004–2008 3.8L V6 Chrysler or Dodge minivan, Ground reaches the MAP sensor through the dark blue with dark green stripe (DK BLU/DK GRN) wire. This is a PCM-provided Ground that's shared with other engine sensors.
CAUTION: Since the PCM supplies this Ground, never apply battery power to it —doing so could damage the PCM. The test below uses your multimeter to safely confirm that this Ground is present and solid.
Here's how to check for Ground:
- 1
Disconnect the MAP sensor from its connector.
- 2
Set your multimeter to DC Volts mode.
- 3
Turn the ignition key to ON —engine OFF.
- 4
Connect the red multimeter lead to the battery's positive (+) terminal.
- 5
Use the black lead to probe the front of the terminal that corresponds to the DK BLU/DK GRN wire.
- 6
You should see between 10 to 12 Volts DC on the multimeter.
Here's how to read your results:
CASE 1: You measured 10 to 12 Volts. That confirms the PCM is supplying a solid Ground and the circuit is working like it should.
With all three tests done, here's where you stand:
- TEST 1: Sensor didn't react to vacuum input.
- TEST 2: Its receiving proper 5 Volt power.
- TEST 3: It has a Ground connection.
All signs point to the sensor itself being bad. Time to replace it.
Here are two MAP sensors I recommend. Using these Amazon affiliate links helps keep the site running —and doesn't cost you a cent extra. Thanks again for your support!
- Standard Motor Products AS217 MAP/BAPP Sensor (Amazon affiliate link).
- Delphi PS10229 MAP Sensor (Amazon affiliate link).
CASE 2: No voltage reading on the multimeter. That means the Ground path is broken somewhere in the circuit.
Double-check your leads and connections first. If you're still getting no reading, it's time to check the continuity of the DK BLU/DK GRN wire between the MAP sensor connector and PCM connector.
Once Ground is restored to this circuit, the MAP sensor will function again.
More 3.8L V6 Chrysler And Dodge Minivan Diagnostic Tutorials
If you're tackling a check engine light or an engine performance problem on your 3.8L V6 equipped minivan, this index can really help. It's packed with practical tutorials written for DIYers and Pros alike.
If this info saved the day, buy me a beer!
