When you see a P0105 code pop up, it’s your car’s computer waving a red flag because something’s not adding up with the Manifold Absolute Pressure (MAP) sensor or the Barometric Pressure (BARO) sensor circuit. I can’t count how many times I’ve tracked down weird drivability issues to these two. These sensors are the backbone for figuring out just how much air is getting pulled into your engine. That air info? It tells the computer how much fuel to add and when to fire the spark plugs. In most vehicles, the MAP and BARO are combined into a single sensor, but whether it’s together or separate, their job is to keep an eye on both the air pressure inside your intake manifold and what’s going on outside, in the atmosphere. If your PCM catches a reading that doesn’t make sense-maybe the voltage is stuck, missing, or just totally out of whack-it’ll log the P0105 code and light up your check engine lamp. Think of it as your car’s way of saying, “I can’t do my job right without good info-help me out here!”
DTC P0105
4518
6 minutes of readingCauses of P0105
From experience, the most common reasons I see for a p0105 trouble code are pretty straightforward. Here’s what usually causes it:
- A vacuum hose to the MAP sensor is disconnected, cracked, or plugged up. This is a classic one.
- The MAP sensor itself has failed or is giving bad readings.
- The BARO sensor is faulty (if it’s a separate unit in your car).
- The throttle position sensor (TPS) is malfunctioning, which can throw off the readings.
- Wiring issues-damaged wires, corroded connectors, or loose plugs in the sensor circuit.
- Vacuum leaks somewhere in the intake manifold, which messes with the pressure readings.
- In rare cases, the PCM (the car’s computer) itself is at fault.
Most often, it’s a simple vacuum hose issue or a bad MAP sensor, but I always check everything to be sure.
Symptoms and dtc P0105
When this code is active, you’ll usually notice a few things. The check engine light will come on-that’s the obvious one. But you might also feel the engine running rough, especially when accelerating or idling. Sometimes the engine will misfire, hesitate, or even backfire through the exhaust. In some cases, the car might stall or refuse to idle at all. But every now and then, the only sign is that pesky check engine light, with no real change in how the car drives-at least at first.
This error can also happen on such car brands as Ford, Toyota, and Hyundai.
Diagnosis steps for P0105 engine code
Let me walk you through how I tackle a P0105 code in the shop, step by step:
- First thing I do-pop the hood and hunt down all the vacuum hoses tied to the MAP sensor and intake manifold. I’m feeling for cracks, loose connections, or lines that have just plain fallen off. Always best to do this with a cool engine.
- Once the hoses check out, I give the MAP sensor a close look. I make sure the electrical connector is solid-no broken locks, no green corrosion, nothing loose. See any powdery stuff on the contacts? That’s usually trouble.
- Then, I listen and look for vacuum leaks around the intake manifold. Sometimes you’ll hear a telltale hiss, or you can spray a little carb cleaner near the intake gasket-if the engine stumbles or revs up, you’ve probably found a leak. Just be smart: stay in a well-ventilated area and keep a fire extinguisher within arm’s reach.
- If everything looks good so far, I’ll plug in a scan tool and pull up live MAP sensor data. I compare what I’m seeing at key-on/engine-off and at idle against what’s normal. Numbers out of line? You might have a bad sensor.
- I also double-check the TPS-the throttle position sensor-since if it’s off, it can mess with your MAP readings.
- Still nothing? Time to break out the multimeter and check wires for continuity and voltage. You want to make sure the PCM is really getting the right info.
- PCM failures are rare, but if you’ve checked everything else and you’re still chasing your tail, don’t rule it out.
My rule of thumb: start with the stuff you can see and touch-hoses, plugs, connectors-before you go chasing electrical ghosts. And always double back to make sure you didn’t miss something simple.
Common Mistakes with the P0105 code
One thing I see way too often: folks throw a brand-new MAP sensor at the problem without even glancing at the hoses or wiring. That’s money down the drain if the root cause is just a cracked hose or a loose plug. Another slip-up? Overlooking a sneaky vacuum leak around the intake or forgetting the throttle position sensor could be at play. And let’s not forget-just clearing the code and hoping it won’t return? That’s just sweeping the dirt under the rug. Always start with a sharp visual inspection before spending a dime on new parts.
Seriousness of obd2 code P0105
Trust me, this isn’t something you want to let slide. Rolling around with obd2 code P0105 hanging over your head is asking for poor mileage, rough running, and-if you ignore it long enough-potential engine damage. The engine could start misfiring or stalling, which can be downright dangerous, especially if it happens in traffic or while merging onto the highway. If you’re dealing with a vacuum leak or a bad sensor, unburned fuel can even roast your catalytic converter. Bottom line: things can spiral fast, so don’t put this fix on the back burner.
Repair solutions for P0105 trouble code
Here’s what I see most often fixes a P0105 code, both from my own wrench time and what the factory recommends:
- Fix or swap out any vacuum hoses that are cracked, disconnected, or leaking at the MAP sensor or intake manifold.
- Replace the MAP sensor or BARO sensor if it’s gone bad (and yes, sometimes they just give up the ghost).
- Repair busted wires or swap out corroded connectors in the sensor circuit. Don’t ignore a crusty plug!
- Seal up any vacuum leaks in the intake manifold-could be as simple as tightening bolts or as involved as replacing a gasket.
- If the throttle position sensor is acting up, get it replaced.
- PCM failures are rare, but if you’ve got one, sometimes a reprogram or outright replacement is the only way to go.
My advice? Start with the hoses and connectors-they’re cheap and quick. Nine times out of ten, the fix is simpler than you think.
Conclusion
Here’s the bottom line: if you’re staring down a P0105, your car’s computer isn’t getting a straight story from the MAP/BARO sensor. That throws the whole engine management system for a loop. Don’t shrug it off-waiting will only lead to bigger headaches and bigger bills. Start with the basics: hoses, connectors, and the sensor. If you’re not comfortable chasing down electrical gremlins, don’t be shy about getting a pro involved. The best way to fix this is to move step by step, starting with simple checks and only moving on to sensors or wiring if you really have to. Don’t let this one wait-your engine’s reliability and your safety are in the balance.
