If you've got a check engine light with a MAP sensor code —or just want to understand what this little sensor actually does— you're in the right place.
This guide explains the MAP sensor on 1990–2009 3.8L V6 Chrysler, Dodge, and Plymouth minivans in plain English.
You'll learn why your engine needs it, how it works, and what can go wrong when it fails.
No tests here —just the background knowledge that makes troubleshooting easier and less frustrating.
By the end, you'll know exactly what the MAP sensor does and be ready to test it with confidence.
Contents of this tutorial:
APPLIES TO: This tutorial applies to the following vehicles:
- 3.8L V6 Chrysler Town & Country: 1994, 1995 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009.
- 3.8L V6 Dodge Caravan: 1996, 1997, 1998, 1999, 2000, 2001.
- 3.8L V6 Dodge Grand Caravan: 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2004, 2005, 2006, 2007, 2008, 2009.
- 3.8L V6 Plymouth Voyager: 1999.
- 3.8L V6 Plymouth Grand Voyager: 1994, 1995, 1996, 1999.
What Does The MAP Sensor Actually Do?
The MAP sensor —short for Manifold Absolute Pressure sensor— keeps the PCM updated on how much pressure is inside the intake manifold. That pressure tells the PCM how much load the engine is under— or put another way, how hard the engine is working.
When you're cruising, there's high vacuum in the intake, and the MAP sensor reports low voltage. Step on the gas, vacuum drops, voltage rises —and the MAP sensor instantly relays that to the PCM. From there, the PCM adjusts fuel injection and ignition timing in real time to keep the engine running smooth.
This type of engine management system is called a "speed-density" fuel management system. The PCM uses the MAP signal, engine RPM, and intake air temp (IAT) signal to estimate air flow and dial in the right fuel mix. No MAP reading? The PCM's flying blind —and that means poor engine performance, hesitation, rough idle, or even a no-start.
Think of the MAP sensor as the PCM's "ears", constantly listening to the engine's breathing so it can fine-tune power, fuel economy, and emissions every second the engine's running.
Where's The MAP Sensor Located On These Minivans?
On the 1990–2009 3.8L V6 Chrysler, Dodge, and Plymouth minivans, the MAP sensor is mounted directly on the intake manifold —in one of two locations, depending on the year:
- 1992–2000: Mounted on the back of the aluminum upper intake manifold plenum, on the side facing the firewall.
- 2001–2010: Mounted on top of the plastic upper intake manifold plenum, near the throttle body.
It's a small, rectangular sensor with a three-wire electrical connector plugged into it. There's no vacuum hose involved —the sensor inserts directly into a machined hole in the plenum itself. No "middle man" hose like you see on other makes and models— it reads vacuum straight from the source.
How The MAP Sensor Works (In Plain English)
The MAP sensor reads vacuum inside the intake manifold and turns that into a voltage signal the PCM can understand. It doesn't move, spin, or open and close —it simply reacts to pressure changes and sends continuous voltage updates.
To do this, the sensor needs three things: a 5 Volt reference from the PCM to power it, a solid Ground to complete the circuit, and a Signal wire that carries its voltage reading back to the PCM.
With power and Ground in place, the MAP sensor continuously tracks intake manifold pressure. Here's how it responds under different engine conditions:
- At idle or coasting: Manifold vacuum is high, and the MAP sensor outputs a low voltage signal —typically around 1.0 to 1.5 Volts.
- Under load or acceleration: Vacuum drops as the throttle opens, and the MAP sensor responds with a higher output —often 4.0 to 4.5 Volts at wide open throttle.
The PCM monitors this voltage in real time and uses it to calculate fuel delivery and spark timing —keeping the engine running smoothly, efficiently, and responsively.
But if the MAP sensor sends a faulty signal —or none at all— the PCM can't make accurate adjustments. That's when you'll start noticing hesitation, poor fuel economy, stalling, or MAP-related trouble codes like P0107 or P0108.
What Happens When The MAP Sensor Fails?
When the MAP sensor fails or sends the wrong signal, the PCM gets confused. It can't calculate engine load correctly, so it ends up delivering the wrong amount of fuel or firing the spark at the wrong time. That throws off the whole balance of the engine.
Here are some common symptoms you'll notice when the MAP sensor isn't working right:
- Rough idle or stalling at stoplights
- Hard starts, especially when the engine is hot
- Black smoke from the tailpipe (running too rich)
- Poor fuel economy
- Hesitation or sluggish acceleration
- Check engine light with MAP sensor codes (we'll cover those next)
Some of these symptoms can be caused by other problems too, which is why a proper test is so important.
MAP Sensor Codes You Might See (And What They Mean)
If the MAP sensor or its circuit has a problem, the PCM will usually set a diagnostic trouble code (DTC) and turn on the check engine light. These are the most common MAP-related codes you'll run into on a 3.8L V6 Chrysler, Dodge, or Plymouth minivan:
- P0106: MAP Sensor Performance Problem —The signal doesn't match expected engine load or changes too slowly. Could be a failing sensor, vacuum leak, or wiring issue.
- P0107: MAP Sensor Circuit Low Voltage —The PCM is seeing a voltage lower than expected. Could mean a short to Ground or a bad sensor.
- P0108: MAP Sensor Circuit High Voltage —The PCM is seeing higher voltage than it should. Could be a short to power or a sensor stuck at high output.
Although these codes don't tell you exactly what's wrong —they do give you a big clue as to what's off with the MAP system.
If you're seeing one of these codes, start with the right test tutorial for your year and model:
- How To Test The MAP Sensor (1996-2000 3.8L V6 Chrysler, Dodge, And Plymouth Minivan).
- How To Test The MAP Sensor (2001-2004 3.8L V6 Chrysler And Dodge Minivan).
- How To Test The MAP Sensor (2004-2007 3.8L V6 Chrysler And Dodge Minivan).
More 3.8L V6 Chrysler, Dodge, And Plymouth Minivan Diagnostic Tutorials
Need help figuring out what's going on with your 3.8L V6 equipped minivan? This index brings together all my step-by-step tutorials in one place, so you can get to the root of the problem faster.
If this info saved the day, buy me a beer!
