This article explains the working principles of a MAP sensor (manifold absolute pressure sensor), lists seven common malfunction symptoms and causes, and explains how to quickly locate the problem using professional auto diagnostic tools like the Autel scanner, as well as common repair methods.
Finally, it addresses some of the most pressing questions car owners have, such as "Can I still drive my car if my MAP sensor is broken?"
The MAP sensor is an important part of the engine system.
The MAP sensor is a crucial component of the engine's fuel injection system. Its primary function is to monitor pressure changes within the intake manifold and convert them into electrical signals that are transmitted to the engine control unit (ECU).
The ECU then uses these signals, combined with data from oxygen sensors, temperature sensors, and other sensors, to calculate the appropriate fuel injection amount and ignition timing, ensuring efficient and stable engine operation under various operating conditions.
The location of the MAP sensor varies depending on the vehicle model, but is commonly found in:
The MAP sensor is usually located on or near the intake manifold.
When the vehicle is started, the ECU provides a reference voltage to the MAP sensor. The piezoresistive or piezoelectric element within the sensor senses subtle changes in intake pressure and converts them into electrical signals.
For example, when you press the accelerator pedal, the throttle opening widens, increasing intake pressure. The MAP sensor then responds with a new voltage signal. The ECU then recalculates the fuel injection rate and ignition timing to ensure efficient engine combustion and control exhaust emissions.
When the MAP sensor is malfunctioning, it can affect engine combustion, fuel consumption, and emissions. Common symptoms include:
👉 For example, a Harley-Davidson motorcycle with a faulty MAP sensor may experience noticeable jitter at idle or even stall.
The check engine light may be on due to a bad MAP sensor.
| Fault Code | Fault Type | Possible Causes |
| P0105 | Circuit Fault | Sensor damage, open/short circuit, intake air leak, ECU malfunction |
| P0106 | Abnormal Signal Range | Sensor miscalibration, intake air blockage/leak, vacuum tube damage |
| P0107 | Low Voltage | Signal wire shorted to ground, sensor failure, throttle valve problem |
| P0108 | Overvoltage | Signal wire shorted, sensor damage, or exhaust blockage |
| P0420 | Low Catalytic Converter Efficiency | Catalyst degradation or oxygen sensor damage |
Using Autel Scanner to read DTCs from the ECU can quickly identify whether the MAP sensor is involved. You can also view the real-time data stream to determine if the sensor is outputting abnormal signals.
Check for damage to the sensor, deterioration or loosening of the vacuum tube, and poor contact in the connectors
Turn on the ignition (without starting the vehicle) and check whether the sensor provides a normal reference voltage (generally approximately 5V).
📌 Further Reading: How to Detect EVAP System Valve Faults Using OBD2 Real-Time Data.
Diagnosed the P0105 fault code using an Autel scanner
Technically, the vehicle will still operate, but the following may occur:
⚠️ Driving with this fault for an extended period may damage the engine and catalytic converter, so continued driving is not recommended.
A: Engine performance degrades, fuel consumption increases, and exhaust emissions fall below standard. The fault light illuminates, prompting the owner to promptly inspect the sensor.
A: The ECU enters protection mode, significantly reducing vehicle power and forcing the vehicle to travel to a repair center at low speeds. Fuel consumption and emissions also deteriorate dramatically.
Although small, the MAP sensor is directly related to engine combustion efficiency and emissions control. If an abnormality occurs, use diagnostic tools to promptly identify the problem and replace or repair it as appropriate to avoid significant losses.
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