P0105 Trouble code definition
Manifold Air Pressure (MAP) Barometric Pressure Sensor Electrical Circuit Problem
What the P0105 code means
P0105 is the general code for a problem with the MAP circuit having an electrical failure or malfunction. The MAP sensor is an integral part of the fuel injection system and provides signals to the Engine Control Unit (ECU) for smooth operation and good fuel economy.
What causes the P0105 code?
The MAP circuit problem may have several causes:
The source of the problem is that the sensor range voltage output is out of the programmed input required by the ECU.
The most common problem is the vacuum hose on the sensor may be cracked, damaged, or kinked.
The wiring or MAP sensor may be bad, brittle, or have a bad connection. They could also be too close to higher voltage consumption components, especially alternators, ignition wires, etc. causing irregular signals.
The sensor itself may be stuck in one output voltage.
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, power, and fuel economy.
If the engine is not in good condition, that it is missing, has poor fuel pressure, or there is an internal issue with the engine like a burned valve, it can prevent the MAP sensor from getting a correct output.
What are the symptoms of the P0105 code?
P0105 code will be usually preceded by the Check Engine Light coming on the dashboard display. The vehicle will most often not run well, idle poorly, accelerate erratically, run rich, and backfire because the MAP sensor and throttle position sensor are not operating together.
How does a mechanic diagnose the P0105 code?
Firstly, code P0105 will be cleared and rechecked to see if it comes back. The mechanic will do this by observing the live data on their scanner while driving. If the code or engine warning light comes back, then the mechanic will need to do a visual inspection to see if the vacuum line and other hoses on the intake system are missing, loose, damaged, or disconnected. If these things appear to be correct, the technician should do a voltage output test on the sensor while the engine is running to determine if the output voltages fluctuate with engine speed and load.
Common mistakes when diagnosing the P0105 code
Diagnostic errors are largely due to not following the correct procedure. First, follow the test procedure in the diagnosis to insure there is no intake air leak like a bad vacuum hose or other air connection. The technician must verify that the voltage output of the MAP sensor is in the correct range and fluctuates with the engine speed. Do not buy a new MAP Sensor unless it is clearly at fault.
How serious is the P0105 code?
The P0105 code will result in poor running of the engine and requires immediate attention. It is imperative to have a technician check it out 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 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 engine warning light came on immediately at start up, and the OBD- II system can be reset and the vehicle will operate normally.
What repairs can fix the P0105 code?
The most common potential repairs to address the P0105 code are as follows:
Verify the code with a scanner. Reset the fault codes and perform a road test.
If the P0105 code comes back, then follow the test procedure.
Inspect the vacuum lines and electrical connector and wiring. Disconnect the electrical connector and then reinstall to insure a fresh electrical connection.
Check for vacuum leaks, loose hoses and clamps on the intake, especially on older cars.
If no problems are found, replace the MAP sensor.
Additional comments for consideration regarding the P0105 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 engine warning 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 P0105 code?
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This article originally appeared on YourMechanic.com as P0105 OBD-II Trouble Code: Manifold Air Pressure (MAP) Barometric Pressure Sensor Electrical Circuit Problem and was authored by John Nelson.