P0107 Trouble code definition
Manifold Air Pressure (MAP) Barometric Pressure Sensor Circuit Low Voltage Input Problem
What the P0107 code means
P0107 is the general code for a problem with the MAP circuit sensor having too low voltage input to the Engine Control Unit (ECU). This means the voltage input to the ECU is .5 volt or less which means that it is not in the correct lower range for proper engine operation.
What causes the P0107 code?
The MAP circuit for low voltage problem may have several causes:
The source of the problem is the sensor range voltage input is less than required by the ECU.
The most common problem is a bad MAP sensor.
The wiring or connector may be bad or have a bad connection, or could be too close to higher voltage consumption components, especially alternators, ignition wires, etc. which results in incorrect output voltage. A poor electrical ground can cause problems also.
The sensor itself may be simply operating out of range from fatigue of the sensor’s internal components.
MAP sensors must operate within specific ranges to send correct signals for the ECU to coordinate with the throttle position sensor to adjust correctly for proper engine operation and may have other codes associated with P0107.
If the engine is not in good condition, is missing, has poor fuel pressure, or has an internal issue with the engine like a burned valve, these things can prevent the MAP sensor from having a correct voltage output. The ECU could also be bad but that is rare.
What are the symptoms of the P0107 code?
P0107 code will be normally preceded by the Check Engine Light coming on the vehicle dashboard display. The vehicle will most often not run well, idle poorly, accelerate erratically, have excessive fuel consumption, and backfire because the MAP sensor and throttle position sensor are not operating together and giving false input to the ECU.
The engine can go into a limp home mode which means it automatically reduces power to protect the engine until the code can be diagnosed and repaired.
How does a mechanic diagnose the P0107 code?
P0107 is diagnosed with an OBD-II scanner. A qualified mechanic should then reset the OBD-II fault codes and road test the vehicle to see if the code comes back. He can observe this by watching data live on his scanner while driving. If the code comes back, then the mechanic will need to do a voltage test with the key on using a multimeter and verifying there is 5 volts input to the MAP sensor and a minimum of .5 to 1 volt output with throttle closed.
With the engine running at idle, it should have minimum 1 volt on the input to the ECU and then increase with engine speed and load. If the voltages are correct within the proper range, then it is most likely a bad MAP sensor and needs replacement.
Common mistakes when diagnosing the P0107 code
Diagnostic errors are largely due to not following the prescribed procedure. First, follow the test procedure in the diagnosis to ensure there is the correct voltage to the sensor and from the sensor to the ECU.
The technician must verify the voltage output of the MAP sensor is in the correct range and fluctuates with the engine speed and has proper voltage. Idle voltage is normally 1 to 1.5 volts and full throttle is usually around 4.5 volts.
Do not buy a new MAP Sensor or ECU unless it is clearly at fault.
How serious is the P0107 code?
The P0107 code will result in poor running of the engine and requires immediate attention. Have the code diagnosed as soon as possible. The MAP sensor issue can cause excessive fuel consumption, rough operation, and difficulty starting in certain circumstances, and can cause other problems including engine damage if continued to be driven.
Occasionally, if no problems are found, the technician can reset the fault codes and then retest.
Often times, if the Check Engine Light came on immediately at start up, then the OBD- II system can be reset and the vehicle will operate normally.
What repairs can fix the P0107 code?
The most common repairs to address the P0107 code are as follows:
Verify the code with an OBD-II scanner. Reset the fault codes and then perform a road test.
If the P0107 code comes back, then follow the test procedure.
Check the MAP sensor voltage in and out along with the electrical connector and wiring. Disconnect the electrical connector and then reinstall to ensure a fresh and clean electrical connection. Then check the voltage output on the MAP sensor to see if it is in the correct range.
At this point determine if the MAP sensor is defective and if it has no or incorrect output, then replace the sensor. If all checks are good, then a final test to determine if the ECU is bad must be done.
Additional comments for consideration regarding the P0107 code
Many vehicles with mileage over 100,000 have momentary sensor problems that usually occur during start up or prolonged stress situations on the drive train.
If the Check Engine Light comes on and the vehicle seems to be operating normally, the OBD-II system can be reset using the scanner and the problem may not reoccur. This is why it is important to verify the fault and reset it before doing any repairs.
Need help with a P0107 code?
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This article originally appeared on YourMechanic.com as P0107 OBD-II Trouble Code: Manifold Air Pressure (MAP) Barometric Pressure Sensor Circuit Low Voltage Input Problem and was authored by John Nelson.