P0105
Manifold Absolute Pressure/Barometric Pressure Circuit Malfunction
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The P0105 code indicates a general malfunction in the Manifold Absolute Pressure (MAP) sensor circuit. The MAP sensor measures the vacuum or pressure inside the intake manifold and sends this information to the engine control module (ECM). The ECM uses this data — along with inputs from the throttle position sensor and engine speed sensor — to determine engine load and calculate the correct amount of fuel to inject and the proper ignition timing.
When the ECM detects that the MAP sensor signal is missing, stuck, or falls completely outside the expected electrical range, it sets this code. The most common cause is a failed MAP sensor, but the small vacuum hose that connects the sensor to the intake manifold is also a frequent culprit. This hose can crack, dry-rot, or come loose, preventing the sensor from reading actual manifold pressure. Wiring issues are less common but should also be checked.
You should address this code within the week. The ECM may enter a reduced-power or limp mode, and without accurate manifold pressure data, the fuel mixture and ignition timing will be incorrect, leading to poor performance, increased emissions, and potential engine damage over time. The MAP sensor itself is typically an inexpensive part and is usually accessible on top of or near the intake manifold, making it a straightforward DIY replacement on most vehicles.
Severity
Symptoms
- •Check Engine Light is on
- •Engine runs rough or stalls
- •Poor acceleration and lack of power
- •Unstable or fluctuating idle speed
- •Increased fuel consumption
- •Engine may not start or is hard to start
Likely Causes
The manifold absolute pressure sensor can fail electrically or mechanically, sending no signal or an out-of-range signal to the ECM.
The MAP sensor reads intake manifold vacuum through a small hose. If this hose is cracked, kinked, or disconnected, the sensor cannot read actual manifold pressure.
Corroded, damaged, or loose wiring and connectors in the MAP sensor circuit can disrupt the electrical signal between the sensor and the ECM.
A leak in the intake manifold gasket or a cracked manifold creates abnormal vacuum levels that cause the MAP sensor signal to fall outside expected parameters.
Rarely, the engine control module's internal MAP sensor driver circuit fails, causing it to misread or not receive the sensor's signal.
Estimated Cost
Professional Repair
Includes parts + labor
Common Fixes
- Replace the MAP sensor
- Inspect and replace cracked or disconnected vacuum hose to the MAP sensor
- Repair or replace corroded wiring and connectors
- Check for and repair intake manifold vacuum leaks
- Clear code and retest after each repair step
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