Code
P0105
GWM
P — Powertrain
- Intake Manifold Absolute Pressure Sensor Circuit / Intake Manifold Barometric Pressure
AI status
Completed
Completed
100%
Causes
- Open or shorted wiring between MAP sensor and ECM
- Corroded, loose or damaged MAP sensor connector
- Failed MAP/BARO sensor
- Blown fuse or poor ground affecting sensor power
- Intake vacuum leak or clogged MAP port/hose
- ECM input fault or internal failure
Symptoms
- Malfunction Indicator Lamp (MIL/Check Engine) illuminated
- Rough idle, stalling or hard starting
- Poor acceleration or reduced engine power
- Increased fuel consumption or lean/rich symptoms
- Hesitation, surging or unstable idle
- Possible limp-home mode depending on vehicle
What to check
- Read and record freeze frame and live data using a scan tool; note MAP/BARO values and related sensors (MAF, TPS, RPM, IAT).
- Verify code is stored and check for other related DTCs.
- Visual inspection of MAP sensor, connector and wiring for corrosion, damage, or oil contamination.
- Backprobe MAP sensor connector: check reference voltage, ground continuity and signal voltage at key ON (engine OFF) and at idle.
- Perform a wiggle test on the harness while monitoring MAP signal for intermittent changes.
- Apply handheld vacuum/boost to MAP sensor while watching live voltage — signal should change smoothly.
Signal parameters
- Reference (supply) voltage: ~5 V (acceptable ~4.5–5.5 V) on the sensor reference pin with key ON.
- Ground: near 0 V with good continuity to vehicle chassis ground/ECM ground.
- Signal voltage at key ON / engine OFF (atmospheric pressure): typically high relative to manifold vacuum — commonly ~3.5–5.0 V depending on sensor and altitude.
- Signal voltage at idle (manifold vacuum present): typically lower than atmospheric and changes smoothly (commonly ~0.5–2.5 V depending on design).
- When vacuum is increased with a hand pump, signal voltage should change proportionally and without stepping or dropouts.
- No significant ripple or noise on the signal line; signal should be stable when vacuum is steady.
Diagnostic algorithm
- Connect a scan tool. Confirm P0105 and record freeze-frame/live MAP/BARO data and related codes.
- Visually inspect MAP sensor, vacuum hose/port and connector for damage, contamination or blockage.
- With key ON (engine OFF) backprobe the connector: verify reference voltage (~5V) and good ground. Repair any open/poor connections.
- Start engine and observe MAP signal at idle. Use a vacuum pump on the MAP port: signal should change smoothly with applied vacuum. If signal does not change, suspect sensor or wiring.
- Wiggle test harness while monitoring signal for intermittent faults; repair chafed wires or damaged pins.
- If wiring and power/ground are good but signal is out of expected range or does not respond to vacuum, replace the MAP sensor.
- After repair, clear codes and perform a road test; verify MAP/BARO values return to normal and code does not recur.
- If fault persists after sensor replacement, perform continuity/resistance checks from sensor connector to ECM pin to rule out internal ECU faults and inspect for blown fuses or poor grounds.
- If suspect ECM input failure, consult manufacturer service information and consider ECU bench testing or replacement only after all wiring and sensors are verified good.
Likely causes
- Damaged wiring or poor connector at MAP sensor
- Failed MAP sensor
- Blown sensor power/ground fuse or poor ground
- Clogged/blocked MAP vacuum port or hose
Fault status
Status
MAP/BARO sensor circuit fault detected — signal out of expected range, open, shorted, or intermittent. Engine control may use default values, causing drivability issues.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email