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P0105 Code Explained: Manifold Absolute Pressure (MAP) / Barometric Pressure Circuit Malfunction Causes, Symptoms & Fixes

A P0105 code indicates an electrical malfunction in the Manifold Absolute Pressure (MAP) or Barometric Pressure sensor circuit, affecting engine load calculations and drivability.

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:

Regardless of the wording, all descriptions indicate the PCM has detected an electrical problem affecting the MAP/BARO sensor circuit.

P0105 Quick Facts

ItemInformation
Diagnostic CodeP0105
Generic DefinitionManifold Absolute Pressure/Barometric Pressure Circuit Malfunction
CategoryPowertrain
SystemAir Intake / Engine Management
Fault TypeElectrical Circuit Fault
SeverityModerate to High
Safe to Drive?Usually for short distances
Common CausesFaulty MAP sensor, damaged wiring, vacuum leak, connector corrosion, PCM fault
Common SymptomsCheck 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:

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:

Typical operating range:

Most modern MAP sensors produce a voltage signal ranging from approximately:

depending on engine load.

What Is the BARO Sensor?

Many vehicles use:

The BARO reading tells the PCM the outside atmospheric pressure.

This information helps compensate for:

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 PCM constantly compares the MAP signal against:

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:

Some manufacturers require multiple failures before illuminating the Check Engine Light.

P0105 vs P0106, P0107 and P0108

CodeDescriptionGeneral Fault
P0105MAP/BARO Circuit MalfunctionElectrical fault
P0106MAP PerformanceSensor operating incorrectly
P0107MAP Circuit Low InputVoltage too low
P0108MAP Circuit High InputVoltage too high
P0109MAP Circuit IntermittentSignal unstable

Think of them this way:

Common Symptoms of P0105

Symptoms vary depending on the severity of the circuit fault.

Common symptoms include:

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:

Can P0105 Cause Hard Starting?

Absolutely.

Incorrect manifold pressure readings affect:

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:

Is P0105 Serious?

P0105 is generally considered a moderately serious to serious diagnostic trouble code.

Ignoring it may result in:

Prompt diagnosis is recommended.

Can You Drive with P0105?

Usually, yes—for short distances if the engine runs smoothly.

Avoid driving if:

Continued driving may increase repair costs.

25 Common Causes of P0105

The most common causes include:

  1. Failed MAP sensor
  2. Faulty BARO sensor
  3. Loose electrical connector
  4. Corroded terminals
  5. Broken signal wire
  6. Broken ground wire
  7. Open power supply circuit
  8. Short to voltage
  9. Short to ground
  10. Vacuum hose leak
  11. Cracked vacuum hose
  12. Intake manifold leak
  13. Damaged intake manifold gasket
  14. Dirty sensor port
  15. Carbon buildup
  16. Wiring harness damage
  17. Rodent damage
  18. Blown fuse
  19. Charging system voltage problems
  20. Poor engine ground
  21. Water intrusion
  22. PCM connector problems
  23. Incorrect aftermarket MAP sensor
  24. PCM software issue
  25. 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:

Before replacement, always verify proper power, ground, and signal voltage.

Vacuum Leaks

Older MAP systems use vacuum hoses that can:

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:

Voltage-drop testing is often more effective than simple continuity checks.

PCM Failure

Although possible, PCM failure is uncommon.

Always eliminate:

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:

Never clear the codes before recording freeze-frame data.

Step 2: Check for Additional Codes

P0105 commonly appears with:

Additional codes often point toward the root cause.

Step 3: Review Freeze-Frame Data

Determine exactly when the fault occurred.

Look for:

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:

Many P0105 faults are found during visual inspection.

Step 5: Inspect the MAP Sensor Connector

Disconnect the connector.

Inspect for:

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:

Replace damaged hoses before further diagnosis.

Step 7: Inspect the Wiring Harness

Follow the harness back toward the PCM.

Look for:

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:

Poor grounds commonly cause intermittent sensor problems.

Step 11: Verify Signal Voltage

Back-probe the MAP signal wire.

Typical readings:

The voltage should change smoothly without sudden spikes or dropouts.

Step 12: Compare Live Data

Compare:

Values should change logically together.

Step 13: Perform a Wiggle Test

With the engine idling, gently move:

Watch for:

Intermittent wiring faults frequently appear during this test.

Step 14: Inspect the Intake Manifold

Look for:

Unmetered air entering the engine may affect MAP readings.

Step 15: Perform a Smoke Test

A smoke machine helps locate:

Even small leaks may cause MAP sensor-related drivability issues.

Step 16: Check the Air Filter and Intake System

Inspect for:

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:

Repair connector issues before condemning the PCM.

Step 20: Review Technical Service Bulletins

Check for manufacturer bulletins involving:

Many manufacturers have released revised components to address recurring MAP sensor faults.

Step 21: Road Test the Vehicle

Monitor live data while driving under:

MAP readings should respond smoothly to changing engine load.

Step 22: Graph Sensor Data

Use the scan tool’s graphing function to monitor:

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:

Whenever possible, use an OEM-quality replacement sensor.

Step 24: Clear Diagnostic Codes

After repairs:

Step 25: Confirm the Repair

Complete several drive cycles.

Verify:

The repair is only complete after the system passes all self-tests.

Common Repairs for P0105

Typical repairs include:

Estimated Repair Costs

RepairTypical 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:

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:

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.

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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.

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