If your OBD-II scanner displays P0105, your vehicle’s Engine Control Module (ECM) or Powertrain Control Module (PCM) has detected a malfunction in the Manifold Absolute Pressure (MAP) sensor or Barometric Pressure (BARO) sensor circuit. The PCM relies on these sensors to determine engine load, air density, and atmospheric pressure so it can accurately control fuel delivery, ignition timing, emissions, and—in turbocharged engines—boost pressure.
The generic OBD-II definition for P0105 is:
Manifold Absolute Pressure/Barometric Pressure Circuit Malfunction
Unlike P0106, which indicates the MAP sensor is operating outside its expected performance range, P0105 points to an electrical or circuit-related problem. The PCM has detected that the MAP or BARO signal is missing, implausible, or otherwise not functioning correctly.
Although the MAP sensor itself is sometimes the culprit, many P0105 codes are actually caused by damaged wiring, poor electrical connections, vacuum hose failures (where applicable), blown fuses, poor grounds, or even charging system issues.
Fortunately, diagnosing P0105 is usually straightforward with a quality scan tool, digital multimeter, and careful inspection of the intake and electrical systems.
Alternate Manufacturer Definitions
Depending on the manufacturer, scan tool, or service manual, P0105 may also appear as:
- Manifold Absolute Pressure Circuit Malfunction
- MAP Sensor Circuit Fault
- MAP/BARO Circuit Malfunction
- Barometric Pressure Sensor Circuit Fault
- Intake Manifold Pressure Sensor Circuit
- MAP Sensor Electrical Fault
- MAP Sensor Signal Fault
- Intake Pressure Sensor Circuit Malfunction
- Absolute Pressure Sensor Circuit Error
- MAP Circuit Failure
Regardless of the wording, all descriptions indicate the PCM has detected an electrical problem affecting the MAP/BARO sensor circuit.
P0105 Quick Facts
| Item | Information |
|---|---|
| Diagnostic Code | P0105 |
| Generic Definition | Manifold Absolute Pressure/Barometric Pressure Circuit Malfunction |
| Category | Powertrain |
| System | Air Intake / Engine Management |
| Fault Type | Electrical Circuit Fault |
| Severity | Moderate to High |
| Safe to Drive? | Usually for short distances |
| Common Causes | Faulty MAP sensor, damaged wiring, vacuum leak, connector corrosion, PCM fault |
| Common Symptoms | Check Engine Light, hesitation, rough idle, poor fuel economy, reduced power |
| Typical Repair Cost | $40–$900+ |
What Does the P0105 Code Mean?
The PCM constantly monitors intake manifold pressure using the MAP sensor.
The MAP sensor measures the amount of vacuum—or positive pressure on turbocharged engines—inside the intake manifold.
Using this information, the PCM calculates:
- Engine load
- Fuel injector pulse width
- Ignition timing
- Air-fuel ratio
- Turbocharger boost
- EGR operation
- EVAP system diagnostics
- Transmission shift strategy
When the MAP sensor signal disappears, becomes electrically invalid, or falls completely outside the expected operating range, the PCM stores P0105.
Unlike a simple sensor performance issue, this code generally indicates the electrical circuit itself has failed or become unreliable.
What Is the MAP Sensor?
The Manifold Absolute Pressure (MAP) sensor measures the amount of pressure inside the intake manifold.
As engine load changes:
- Vacuum changes
- Pressure changes
- Sensor voltage changes
- PCM adjusts fuel and timing
Typical operating range:
- Idle: High vacuum
- Moderate throttle: Reduced vacuum
- Wide-open throttle: Near atmospheric pressure
- Turbocharged engines: Positive boost pressure
Most modern MAP sensors produce a voltage signal ranging from approximately:
- 0.5 volts
- to
- 4.5 volts
depending on engine load.
What Is the BARO Sensor?
Many vehicles use:
- A dedicated Barometric Pressure sensor
- A MAP sensor that also measures barometric pressure during startup
- A combined MAP/BARO sensor
The BARO reading tells the PCM the outside atmospheric pressure.
This information helps compensate for:
- High elevation
- Weather changes
- Air density
- Turbocharger control
- Fuel delivery
If the BARO value becomes implausible, P0105 may also be stored.
How the MAP Sensor Works
Inside the sensor is a pressure-sensitive silicon diaphragm.
As manifold pressure changes:
- The diaphragm flexes
- Internal resistance changes
- Output voltage changes
- The PCM interprets the signal
The PCM constantly compares the MAP signal against:
- Throttle Position Sensor
- Mass Air Flow Sensor (if equipped)
- Intake Air Temperature
- Engine RPM
- Barometric Pressure
- Oxygen Sensors
If the MAP signal no longer behaves logically, P0105 is triggered.
Where Is the MAP Sensor Located?
Most MAP sensors are installed:
Directly on the Intake Manifold
Many engines mount the sensor directly into the manifold.
On the Intake Plenum
Some engines install the sensor on the upper intake.
Connected by a Vacuum Hose
Older vehicles may use a remote-mounted sensor connected by a vacuum hose.
Integrated into the Intake Assembly
Some manufacturers integrate the sensor into the intake manifold or throttle body.
Always verify the sensor location before diagnosis.
How the PCM Detects P0105
The PCM expects the MAP signal to respond smoothly to changes in engine load.
It also checks whether the electrical circuit remains functional.
P0105 may be stored if:
- Signal disappears
- Voltage is implausible
- Circuit opens
- Circuit shorts
- Sensor loses power
- Sensor loses ground
- Signal conflicts with BARO readings
- MAP readings don’t match throttle position
- Signal remains fixed
Some manufacturers require multiple failures before illuminating the Check Engine Light.
P0105 vs P0106, P0107 and P0108
| Code | Description | General Fault |
| P0105 | MAP/BARO Circuit Malfunction | Electrical fault |
| P0106 | MAP Performance | Sensor operating incorrectly |
| P0107 | MAP Circuit Low Input | Voltage too low |
| P0108 | MAP Circuit High Input | Voltage too high |
| P0109 | MAP Circuit Intermittent | Signal unstable |
Think of them this way:
- P0105 – Something is wrong with the circuit.
- P0106 – The readings don’t make sense.
- P0107 – Voltage is too low.
- P0108 – Voltage is too high.
- P0109 – The signal keeps dropping in and out.
Common Symptoms of P0105
Symptoms vary depending on the severity of the circuit fault.
Common symptoms include:
- Check Engine Light
- Rough idle
- Hesitation
- Poor acceleration
- Engine stumbling
- Hard starting
- Reduced fuel economy
- Black exhaust smoke
- Rich fuel mixture
- Lean fuel mixture
- Reduced engine power
- Limp mode
- Transmission shift issues
- Failed emissions inspection
Some vehicles may appear to run normally while others become nearly undriveable.
Can P0105 Cause Poor Fuel Economy?
Yes.
Without accurate manifold pressure information, the PCM estimates engine load using substitute values.
This often causes:
- Rich fuel mixtures
- Excess fuel consumption
- Increased emissions
- Reduced performance
Can P0105 Cause Hard Starting?
Absolutely.
Incorrect manifold pressure readings affect:
- Startup fuel enrichment
- Ignition timing
- Air-fuel ratio
The engine may crank longer before starting or require multiple attempts.
Can P0105 Cause Turbo Problems?
Yes.
Turbocharged engines rely heavily on accurate MAP readings.
An incorrect MAP signal may cause:
- Reduced boost
- Wastegate control issues
- Limp mode
- Overboost protection
- Underboost conditions
Is P0105 Serious?
P0105 is generally considered a moderately serious to serious diagnostic trouble code.
Ignoring it may result in:
- Poor drivability
- Increased emissions
- Poor fuel economy
- Engine hesitation
- Stalling
- Catalytic converter damage
- Turbocharger performance issues
Prompt diagnosis is recommended.
Can You Drive with P0105?
Usually, yes—for short distances if the engine runs smoothly.
Avoid driving if:
- Engine stalls
- Severe hesitation occurs
- Reduced power becomes dangerous
- Limp mode activates
- Multiple warning lights appear
Continued driving may increase repair costs.
25 Common Causes of P0105
The most common causes include:
- Failed MAP sensor
- Faulty BARO sensor
- Loose electrical connector
- Corroded terminals
- Broken signal wire
- Broken ground wire
- Open power supply circuit
- Short to voltage
- Short to ground
- Vacuum hose leak
- Cracked vacuum hose
- Intake manifold leak
- Damaged intake manifold gasket
- Dirty sensor port
- Carbon buildup
- Wiring harness damage
- Rodent damage
- Blown fuse
- Charging system voltage problems
- Poor engine ground
- Water intrusion
- PCM connector problems
- Incorrect aftermarket MAP sensor
- PCM software issue
- Internal PCM failure (rare)
The vast majority of P0105 repairs involve the sensor, connector, vacuum system, or wiring—not the PCM.
Faulty MAP Sensor
The internal pressure-sensing element can fail from:
- Heat
- Vibration
- Oil contamination
- Moisture
- Age
Before replacement, always verify proper power, ground, and signal voltage.
Vacuum Leaks
Older MAP systems use vacuum hoses that can:
- Crack
- Collapse
- Disconnect
- Leak
A leaking hose may cause inaccurate pressure readings even if the sensor itself is functioning correctly.
Wiring Problems
Electrical faults are among the most common causes of P0105.
Inspect for:
- Chafed insulation
- Broken wires
- Melted wiring
- Loose terminals
- Corrosion
- Oil contamination
- Water intrusion
Voltage-drop testing is often more effective than simple continuity checks.
PCM Failure
Although possible, PCM failure is uncommon.
Always eliminate:
- Sensor failure
- Wiring faults
- Vacuum leaks
- Connector damage
- Charging system problems
before replacing the PCM.
Because the MAP sensor directly affects fuel delivery, ignition timing, transmission shifting, emissions, and turbocharger operation, proper diagnosis is critical. While replacing the sensor may seem like the obvious fix, wiring issues, vacuum leaks, poor grounds, and connector problems are often responsible for triggering P0105.
The following diagnostic procedure follows the same process used by professional technicians to accurately locate the source of the fault.
How to Diagnose the P0105 Code
Step 1: Verify the Code
Connect a professional scan tool and record:
- Stored DTCs
- Pending DTCs
- Freeze-frame data
- MAP sensor voltage
- BARO readings
- Intake Air Temperature
- Engine RPM
- Battery voltage
- Fuel trims
- Throttle position
Never clear the codes before recording freeze-frame data.
Step 2: Check for Additional Codes
P0105 commonly appears with:
- P0106 MAP Sensor Performance
- P0107 MAP Circuit Low Input
- P0108 MAP Circuit High Input
- P0109 MAP Circuit Intermittent
- P0113 Intake Air Temperature High
- P0171 System Too Lean
- P0172 System Too Rich
- P0300 Random Misfire
Additional codes often point toward the root cause.
Step 3: Review Freeze-Frame Data
Determine exactly when the fault occurred.
Look for:
- Engine load
- Vehicle speed
- RPM
- Coolant temperature
- MAP voltage
- Battery voltage
- Fuel trims
This information often reveals whether the problem occurred at idle, during acceleration, or while cruising.
Step 4: Perform a Visual Inspection
Inspect the engine bay carefully.
Look for:
- Broken connectors
- Damaged wiring
- Oil contamination
- Water intrusion
- Vacuum hose damage
- Intake manifold cracks
- Loose sensor mounting
Many P0105 faults are found during visual inspection.
Step 5: Inspect the MAP Sensor Connector
Disconnect the connector.
Inspect for:
- Bent pins
- Green corrosion
- Moisture
- Loose terminals
- Broken locking tabs
- Oil contamination
- Pins pushed backward
Repair connector damage before replacing the sensor.
Step 6: Inspect Vacuum Hoses (If Equipped)
Older vehicles may use a vacuum hose between the intake manifold and the MAP sensor.
Inspect for:
- Cracks
- Soft spots
- Oil contamination
- Loose fittings
- Kinks
- Collapsed hoses
Replace damaged hoses before further diagnosis.
Step 7: Inspect the Wiring Harness
Follow the harness back toward the PCM.
Look for:
- Melted insulation
- Pinched wires
- Chafed harnesses
- Rodent damage
- Previous repairs
- Heat damage
Pay special attention to locations where the harness contacts engine components.
Step 8: Check Battery Voltage
Measure battery voltage with the engine off and running.
A weak battery or unstable charging system can create false MAP sensor faults.
Step 9: Verify the 5-Volt Reference Circuit
Using a digital multimeter:
Verify the sensor receives the proper 5-volt reference from the PCM.
If reference voltage is missing, inspect the wiring and related sensors that share the same circuit.
Step 10: Verify Ground Integrity
Perform a voltage-drop test on the MAP sensor ground.
Inspect:
- Engine grounds
- Chassis grounds
- Ground splices
- Battery ground cable
Poor grounds commonly cause intermittent sensor problems.
Step 11: Verify Signal Voltage
Back-probe the MAP signal wire.
Typical readings:
- Key On, Engine Off: Approximately 4.0–4.8 volts
- Idle: Approximately 0.9–1.8 volts
- Wide Open Throttle: Approximately 4.0–4.8 volts
The voltage should change smoothly without sudden spikes or dropouts.
Step 12: Compare Live Data
Compare:
- MAP readings
- BARO readings
- Throttle Position
- RPM
- MAF readings (if equipped)
Values should change logically together.
Step 13: Perform a Wiggle Test
With the engine idling, gently move:
- MAP connector
- Wiring harness
- PCM connector
Watch for:
- Voltage spikes
- Signal loss
- Rough idle
- Engine stumble
Intermittent wiring faults frequently appear during this test.
Step 14: Inspect the Intake Manifold
Look for:
- Cracks
- Vacuum leaks
- Loose manifold bolts
- Damaged gaskets
Unmetered air entering the engine may affect MAP readings.
Step 15: Perform a Smoke Test
A smoke machine helps locate:
- Vacuum leaks
- Intake gasket leaks
- PCV leaks
- EVAP leaks
Even small leaks may cause MAP sensor-related drivability issues.
Step 16: Check the Air Filter and Intake System
Inspect for:
- Clogged air filter
- Damaged intake tubing
- Loose clamps
- Obstructions
Restricted airflow may contribute to incorrect load calculations.
Step 17: Verify BARO Operation
Compare barometric pressure readings with local atmospheric pressure.
Large discrepancies may indicate a faulty BARO sensor or incorrect MAP calculation.
Step 18: Inspect Charging System Output
Verify alternator voltage remains stable under varying electrical loads.
Voltage spikes can interfere with sensor operation.
Step 19: Inspect PCM Connectors
Disconnect the PCM following manufacturer procedures.
Inspect for:
- Moisture
- Corrosion
- Bent pins
- Loose connectors
Repair connector issues before condemning the PCM.
Step 20: Review Technical Service Bulletins
Check for manufacturer bulletins involving:
- MAP sensor updates
- PCM software revisions
- Connector improvements
- Harness routing changes
Many manufacturers have released revised components to address recurring MAP sensor faults.
Step 21: Road Test the Vehicle
Monitor live data while driving under:
- Idle
- Light throttle
- Moderate acceleration
- Highway cruising
- Deceleration
MAP readings should respond smoothly to changing engine load.
Step 22: Graph Sensor Data
Use the scan tool’s graphing function to monitor:
- MAP sensor voltage
- Throttle position
- Engine RPM
- Fuel trims
Graphing often reveals irregular signal behavior that numerical values can miss.
Step 23: Replace the MAP Sensor (If Necessary)
Only replace the sensor after confirming:
- Proper power
- Proper ground
- Correct signal circuit
- No vacuum leaks
- No wiring faults
Whenever possible, use an OEM-quality replacement sensor.
Step 24: Clear Diagnostic Codes
After repairs:
- Clear all DTCs
- Restart the engine
- Verify normal idle
- Observe live MAP readings
Step 25: Confirm the Repair
Complete several drive cycles.
Verify:
- No pending codes
- No stored codes
- Stable idle
- Smooth acceleration
- Correct MAP voltage
- Normal fuel trims
- Check Engine Light remains off
The repair is only complete after the system passes all self-tests.
Common Repairs for P0105
Typical repairs include:
- Replacing the MAP sensor
- Repairing damaged wiring
- Replacing corroded connectors
- Repairing vacuum leaks
- Replacing cracked vacuum hoses
- Cleaning sensor ports
- Repairing engine grounds
- Updating PCM software
- Replacing the BARO sensor (if equipped)
- Replacing the PCM (rare)
Estimated Repair Costs
| Repair | Typical Cost |
|---|---|
| Vacuum hose replacement | $20–$80 |
| Electrical connector repair | $75–$250 |
| Wiring repair | $100–$350 |
| Intake manifold gasket | $200–$700 |
| MAP sensor replacement | $120–$450 |
| BARO sensor replacement | $150–$500 |
| PCM software update | $100–$250 |
| PCM replacement | $1,000–$3,000+ |
Repair costs vary depending on vehicle make, labor rates, and OEM versus aftermarket parts.
Common Diagnostic Mistakes
Avoid these common errors:
- Replacing the MAP sensor before testing the circuit
- Ignoring vacuum hose leaks
- Skipping voltage-drop testing
- Assuming the PCM has failed
- Overlooking charging-system voltage issues
- Failing to inspect connector terminals
- Ignoring Technical Service Bulletins
- Using low-quality aftermarket sensors
- Clearing codes before saving freeze-frame data
- Forgetting to verify BARO readings
Most P0105 codes are caused by wiring, connectors, vacuum leaks, or sensor failure—not a defective PCM.
Manufacturer-Specific Notes
Ford
EcoBoost engines commonly experience wiring fatigue near the intake manifold. Verify harness routing before replacing the MAP sensor.
General Motors
Broken vacuum lines and damaged intake manifold gaskets are common causes of P0105 on older GM trucks and SUVs.
Toyota & Lexus
Use OEM or Denso MAP sensors whenever possible. Some aftermarket sensors produce inaccurate voltage signals.
Honda & Acura
Inspect the sensor connector for oil contamination and ensure the intake manifold passage is free of carbon buildup.
Nissan & Infiniti
Cracked intake boots and poor engine grounds frequently contribute to MAP sensor circuit faults.
BMW & MINI
Turbocharged engines often require inspection of boost pipes, vacuum plumbing, and charge-air connections before replacing the sensor.
Volkswagen & Audi
Verify manifold pressure readings against requested boost values using a factory-capable scan tool.
Mercedes-Benz
Inspect the intake manifold pressure sensor seal and connector for moisture intrusion.
Hyundai & Kia
Check the integrity of the shared 5-volt reference circuit before replacing the MAP sensor.
Subaru
Modified turbocharger systems and aftermarket boost controllers can cause incorrect MAP sensor readings if improperly installed.
Preventative Maintenance
Reduce the likelihood of P0105 by:
- Replacing damaged vacuum hoses promptly
- Inspecting electrical connectors during routine service
- Keeping engine grounds clean and tight
- Maintaining the charging system
- Replacing clogged air filters
- Repairing intake leaks immediately
- Avoiding low-quality aftermarket sensors
- Inspecting wiring near hot engine components
- Addressing Check Engine Lights promptly
Routine inspections help prevent many MAP sensor circuit failures before they become major drivability issues.
Frequently Asked Questions
What does P0105 mean?
P0105 indicates the PCM has detected an electrical malfunction in the Manifold Absolute Pressure (MAP) or Barometric Pressure (BARO) sensor circuit.
Is P0105 serious?
Yes. While the vehicle may remain drivable, the fault can cause poor performance, increased fuel consumption, hesitation, and emissions problems if left unresolved.
Can I drive with P0105?
Short trips are usually possible if the engine runs normally. Avoid driving if the vehicle enters limp mode, stalls, or experiences severe hesitation.
Does P0105 always mean the MAP sensor is bad?
No. Wiring faults, poor grounds, vacuum leaks, damaged connectors, and charging system problems are all common causes.
Can a vacuum leak trigger P0105?
Yes. On systems that use a vacuum hose to the MAP sensor, leaks can result in incorrect pressure readings and trigger the code.
How much does it cost to repair P0105?
Repairs range from around $20 for a vacuum hose replacement to more than $3,000 for a rare PCM replacement. Most repairs fall between $120 and $450.
Will disconnecting the battery clear P0105?
It may temporarily erase the stored code, but the Check Engine Light will return if the underlying fault has not been repaired.
Can a bad MAP sensor affect fuel economy?
Absolutely. Incorrect manifold pressure readings can cause rich or lean fuel mixtures, increasing fuel consumption and emissions.
What’s the difference between P0105 and P0106?
P0105 indicates an electrical or circuit malfunction, while P0106 indicates the MAP sensor is functioning but its readings are outside the expected performance range.
Final Thoughts
The P0105 Manifold Absolute Pressure (MAP) / Barometric Pressure Circuit Malfunction code is an important warning that the PCM is no longer receiving reliable pressure information needed to manage engine operation. Although replacing the MAP sensor may solve the issue in some cases, damaged wiring, poor grounds, vacuum leaks, corroded connectors, and charging-system problems are frequently the real cause.
Following a structured diagnostic process—starting with visual inspections, verifying power, ground, and signal integrity, checking for intake leaks, and confirming sensor operation with live scan data—will help ensure an accurate repair while preventing unnecessary parts replacement.
Related Pro Street Diagnostic Guides
Related Air Intake & Fuel System Codes
- P0100 Mass Air Flow Circuit Malfunction
- P0101 Mass Air Flow Sensor Performance
- P0102 Mass Air Flow Sensor Circuit Low Input
- P0103 Mass Air Flow Sensor Circuit High Input
- P0104 Mass Air Flow Sensor Circuit Intermittent
Complete OBD-II Diagnostic Guides
- Complete OBD-II P-Code Library
- Complete B-Code OBD-II Codes: https://my.prostreetonline.com/dtc-doctor/b-code-obd-ii-codes/
- Complete C-Code OBD-II Codes: https://my.prostreetonline.com/dtc-doctor/c-code-obd-ii-codes/
If P0105 is accompanied by fuel-trim, misfire, or boost-related trouble codes, diagnosing the MAP sensor circuit first can often resolve multiple drivability issues with a single repair.
