Fault code P0107 – a step-by-step guide to diagnosing and fixing it

Trouble code P0107 indicates that the manifold absolute pressure (MAP) sensor’s voltage input is too low. The sensor is a resistor which responds to changes in the manifold pressure, affecting the resistance of the device and its voltage signal. The powertrain control module (PCM) uses this information to regulate the fuel supply. The normal range is usually from 1 V to 4.5 V. The DTC is set when the PCM sees that the voltage is lower than 0.5 V or 0.25 V.

• It is commonly caused by a defective MAP sensor. The device can get damaged or be affected by build-ups of contaminants, such as dirt and debris.
• An open or short in the signal circuit or volt reference circuit. This may occur due to faulty wires or thermal, mechanical or chemical damage.
• Electromagnetic interference or a bad electrical connector. If within close proximity of high-voltage components like the engine alternator, the connection could be affected. If the connector is loose or cracked the contacts may corrode due to exposure to moisture and dirt.
• Insufficient fuel pressure due to damaged or worn components in the fuel system.
• Damage to the engine components, such as the valves.

• Activation of the check engine light on the dashboard
• Rough idling
• Poor acceleration
• Long cranking times and difficulty starting the engine
• Increased fuel consumption
• Black smoke coming out of the exhaust pipe

• First connect an OBD2 scanner or similar scan tool to the vehicle via the data link connector port. You can check whether other DTCs are present which could indicate the underlying cause of the fault. It is also possible to use it to measure the sensor’s voltage while the vehicle is on and the engine is running.
• If the reading is below 0.5 V, turn off the engine and unplug the device before testing the volt reference circuit with a digital multimeter. If this reference voltage is not there, check whether it is detectable at the PCM connector. When it is detected at the PCM connector but not the MAP harness connector, this indicates that there is an open circuit between the connectors. Fix this by replacing the faulty components.
• When the MAP connector has a 5-volt reference, connect the volt reference circuit to the signal circuit (e.g. using a jumper). Then monitor the sensor’s voltage again using the scan tool. The reading should be between approximately 4.5 V and 5 V. If this is the case, the device itself should be replaced. If the reference volts aren’t coming through, it is likely that there is a short or open in the signal circuit. Replace the broken wires and check this one more time.
• Sometimes there are visible signs of damage that can easily be found during an inspection. Check the wiring, connector contacts and sensor body for cracks, fatigue damage, melting, corrosion, and other defects. Replace or repair defective components. It may be possible to remove traces of corrosion from the electrical contacts and restore them using a specialised contact cleaner.
• Examine critical engine components that could affect the readings. Repair and replace parts if necessary.