Code
P0105
MITSUBISHI
P — Powertrain
BARO./MAP sensor
Views:
UK: 20
EN: 64
RU: 64
AI status
Completed
Completed
100%
Causes
- Damaged or corroded sensor connector or wiring (open, short to ground, short to Vref)
- Faulty BARO/MAP sensor element
- Loss of reference voltage (typically 5V) or ground to the sensor
- Vacuum leaks or intake air leaks altering MAP readings
- ECM input circuit fault or poor ECM ground
- Mechanical blockage or restriction in the sensor or intake (rare)
Symptoms
- Check Engine Light (MIL) illuminated with P0105 stored
- Hard starting or rough idle
- Poor fuel economy and drivability (surging, hesitation, stalling)
- Reduced engine power or limp mode on some models
- Incorrect barometric correction causing poor fuel/ignition control
What to check
- Retrieve freeze frame and live MAP/BARO sensor data with a scan tool; note values at key ON and engine at idle
- Visual inspection of sensor connector and wiring for damage, corrosion, or pin push-out
- Check for intake vacuum leaks and inspect vacuum hoses and PCV system
- Verify ECM grounds and battery/charging system voltages
- Compare MAP reading to known ambient/barometric pressure (key ON engine OFF)
- Back-probe sensor pins and measure reference, signal and ground voltages while monitoring live data
Signal parameters
- Sensor supply (reference) typically 5 V from ECM
- Sensor ground approximately 0 V (vehicle chassis/ECM ground)
- MAP/BARO signal commonly 0.5–4.5 V range depending on vacuum/pressure (exact values model-specific)
- At atmospheric pressure (engine off) BARO signal normally near the high end of the sensor’s voltage range (check factory spec)
- MAP signal decreases with increasing vacuum and increases with manifold pressure/boost
Diagnostic algorithm
- Confirm P0105 is current and record freeze-frame and live MAP/BARO values with a scan tool.
- Visually inspect sensor, connector and wiring for damage, corrosion or oil/contaminant ingress; repair as needed.
- With key ON engine OFF, measure sensor reference voltage at the connector; expect ~5 V (confirm against service data).
- Measure sensor ground continuity to chassis/ECM ground; repair poor grounds.
- Back-probe the signal wire with key ON engine OFF and compare BARO reading to known local barometric pressure (scan tool or reference source).
- Start engine and observe MAP signal at idle and during throttle changes; verify signal moves smoothly and plausibly.
- Apply a handheld vacuum/pressure pump to the MAP port (if accessible) and confirm signal changes correspondingly; if not, replace sensor.
- If wiring, voltages and sensor bench checks are good, swap with a known-good sensor or replace the MAP/BARO sensor and retest.
- If problem persists after sensor replacement, check ECM input circuit and perform pinpoint tests from factory manual or consult dealer-level diagnostics.
- Clear codes and perform a road test to verify the fault does not return.
Likely causes
- Wiring harness damage or connector corrosion at the BARO/MAP sensor
- Failed MAP/BARO sensor (contaminated or internally shorted)
- Lost 5V reference or ground to the sensor
- Large vacuum leak causing out-of-range signal
Fault status
Status
P0105 — Manifold Absolute Pressure/Barometric Pressure Circuit Malfunction: ECM detects implausible or out-of-range BARO/MAP sensor signal; MIL on.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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