P0105 Code: MAP/Barometric Pressure Sensor Circuit Malfunction
The PCM lost a usable signal from the manifold pressure sensor: dropouts, noise or values it can't decode.
At a glance
Severity: Moderate
- Meaning
- MAP/Barometric Pressure Sensor Circuit Malfunction
- System
- Fuel & Air Metering · Powertrain
- Safe to drive?
- With caution
- Typical repair cost
- $0–$1,200
- DIY difficulty
- Easy
The manifold absolute pressure (MAP) sensor tells the PCM how much vacuum or boost is in the intake, and on many engines it also samples barometric pressure at key-on before the engine cranks. P0105 is the general circuit code: the PCM found the signal unusable but did not, or cannot, classify it as simply too low (P0107) or too high (P0108). On speed-density engines that have no MAF sensor, which includes many Chrysler, Dodge and Jeep engines and a number of Honda and Hyundai/Kia four-cylinders, MAP is the main load input for fuel, spark and shift timing, so a fault here hits drivability hard. The sensor lives on a 5-volt reference from the PCM that it usually shares with other sensors, so P0105 arriving together with throttle position or reference voltage codes points at that shared circuit rather than the MAP sensor itself.
Can I keep driving? Drive only as far as you need to. On engines that fuel from MAP, a circuit dropout can cause stalling, bucking or harsh shifts, so avoid highway merges and heavy traffic until it's diagnosed.
How to read P0105
- P Powertrain
- 0 Generic (SAE)
- 1 Fuel & air metering
- 05 Specific fault
Symptoms
- Check engine light that may come and go
- Stalling or bucking episodes that appear and disappear
- Alternating black smoke and lean hesitation as the reading jumps
- Late, harsh or erratic automatic transmission shifts
- Hard starting when the fault is present at key-on
- MAP value in live data flicking between normal and extreme numbers
Possible causes
Ranked by how often each cause is behind this code (editorial estimate).
- Loose, corroded or water-damaged MAP sensor connector
- Intermittent break or chafe in the MAP wiring harness
- MAP sensor electronics failing
- Shared 5-volt reference dragged down by another shorted sensor
- Oil or fuel residue from the PCV system inside the sensor
- PCM input or reference driver fault
Diagnosis step by step
Read freeze frame and companion codes
Check the conditions when P0105 set and what else is stored. P0105 together with P0120, P0122 or P0641 means several sensors lost their 5-volt reference at the same moment, which moves the search away from the MAP sensor. P0110 at the same time suggests a combined pressure and temperature sensor sharing one plug.
Tools: OBD-II scanner
Compare key-on MAP with barometric pressure
Before starting, MAP should equal outside air pressure: about 101 kPa (29.9 inHg) near sea level and about 84 kPa (24.8 inHg) at Denver's altitude. On a typical non-turbo sensor that is roughly 4.5 V at sea level. At warm idle expect about 25 to 35 kPa, or roughly 1.0 to 1.5 V.
Tools: OBD-II scanner
Graph MAP while flexing the harness
With the engine idling, graph the MAP reading and gently move the connector and the harness section by section. A spike to barometric pressure or a drop toward zero that repeats when you touch one spot pins down the wiring fault.
Tools: OBD-II scanner
Measure reference, ground and signal
Key on, back-probe all three wires. The reference should read 4.9 to 5.1 V, the ground under 0.1 V against battery negative, and the signal somewhere in between. A low reference that is also low at the throttle position sensor means a shared circuit fault; unplug the sensors on that circuit one by one until the 5 V returns.
Tools: Multimeter
Inspect the sensor, port and seal
Remove the sensor and look for oil or fuel residue in its nipple, a damaged O-ring and cracks in the housing. On remote-mounted sensors, check that the vacuum hose isn't split, collapsed or partly filled with oil, which can make the reading erratic.
Tools: Screwdriver, Flashlight
Where the parts are
- 1Ignition coil
- 2Spark plug
- 3Fuel injector
- 4Camshaft sensor
- 5Crankshaft sensor
- 6Engine computer (ECM)
- 7Intake manifold
Repair options & costs
| Repair | DIY? | Estimated cost |
|---|---|---|
| Clean and secure the MAP connector | Yes | $0–$40 |
| Replace MAP sensor | Yes | $60–$250 |
| Replace a sensor shorting the shared 5-volt reference | No | $60–$300 |
| Repair MAP wiring harness | No | $100–$320 |
| PCM diagnosis and repair or replacement | No | $400–$1,200 |
Rough US estimates for parts and labor; shop rates vary by region. Not a quote.
Notes by brand
Jeep
Jeep's 4.0-liter inline-six, the 3.6-liter Pentastar V6 and the Hemi V8s run without a MAF sensor, so MAP is the primary load input. MAP circuit faults on these engines tend to cause more obvious stalling and rough running than the same fault on a MAF-equipped engine.
Emissions / smog test impact
Will fail
An active check engine light fails the OBD-II portion of US emissions testing. Because P0105 is often intermittent, confirm the repair over several drives and wait for the readiness monitors to show complete before retesting.
Frequently asked questions
What's the difference between a MAP sensor and a MAF sensor?
A MAF sensor measures the mass of air flowing into the engine directly, while a MAP sensor measures pressure in the intake manifold, from which the PCM calculates airflow. Many engines have both: the MAF for fueling and the MAP for barometric correction, EGR checks or boost control.
Can a MAP circuit fault affect how my automatic transmission shifts?
Yes. The transmission controller uses engine load, often calculated from MAP, to decide shift points and line pressure. When the MAP signal drops out, shifts can become late, harsh or oddly timed until the fault is fixed.
Why did P0105 set together with throttle position codes?
Both sensors usually get their 5-volt reference from the same PCM circuit. If one sensor on that circuit shorts internally or its wire rubs through, the reference collapses and every sensor on it reports a fault at once.
Is it safe to clean a MAP sensor?
You can carefully clear oil residue from the sensor port with electrical contact cleaner, but don't push anything into the opening, since the pressure element behind it is fragile. If the sensor is soaked in oil, fix the PCV problem too or it will happen again.