P0106 Trouble code definition
Manifold Air Pressure (MAP) Barometric Pressure Sensor Electric Circuit Output Range and Performance Problem
What the P0106 code means
P0106 is the general code for a problem with the MAP circuit having problem of incorrect voltage output range or an issue with engine performance. 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 along with proper performance and power.
What causes the P0106 code?
The MAP circuit for range and performance problem may have several causes:
The source of the problem is that the MAP sensor range voltage output is incorrect and out of the programmed input required by the ECU.
The most common problem is an air intake system vacuum or intake hose being loose, cracked, or missing it’s plastic fittings and clamps.
The wiring or MAP sensor may be bad, brittle, cracked, have a bad connection, or could be too close to the higher voltage consumption components, especially alternators, ignition wires, etc. A poor electrical ground can cause problems also.
The sensor itself may simply be operating out of range from fatigue in it’s internal components.
MAP sensors must operate within specific ranges to send correct signals for the ECU to coordinate with the throttle position sensor and adjust correctly for proper engine operation.
If the engine is not in good condition, 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.
The ECU could also be bad but that is rare.
What are the symptoms of the P0106 code?
P0106 code will be generally preceded by the Check Engine Light coming on the dashboard display. The vehicle in most cases will not run well, idle poorly, accelerate erratically, run rich, and backfire because the MAP sensor and throttle position sensor will not operate together properly.
How does a mechanic diagnose the P0106 code?
P0106 is diagnosed with an OBD- II scanner. A qualified technician should then reset the OBD- II fault codes and perform a road test of the vehicle to see if the code comes back. He can observe this by watching live data streaming on his scanner while driving. If the code comes back, then the mechanic will need to do a close 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 on the engine. Check that all grounds are operating correctly, since any ground related to the ECU could cause signal fluctuations from sensors.
Common mistakes when diagnosing the P0106 code.
Diagnostic errors are largely due to not following the proper procedure. First, follow the test procedure in the diagnosis to insure there is no intake air leak like a bad vacuum hose or connection. The technician must verify that the voltage output of the MAP sensor is correct and fluctuates with the engine speed and 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 P0106 code?
The P0106 code will result in poor running of the engine and requires immediate attention. Have the vehicle 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 damage if continued to be driven. Occasionally, if no problems are found, the technician can reset the fault codes and retest it to see if the code or engine light comes back on.
Often times, if the engine warning light comes on immediately at startup, then the OBD- II system can be reset and the vehicle will operate normally.
What repairs can fix the P0106 code?
The most common potential repairs to address the P0106 code are as follows:
Verify the code with an OBD-II scanner. Reset the fault codes and perform a road test of the vehicle.
If the P0106 code comes back, then follow the test procedure.
Inspect the vacuum lines and intake hoses for cracked, loose or missing parts and electrical connector and wiring. Disconnect the electrical connector and then reinstall to insure a fresh and positive electrical connection. Then check the voltage output on the MAP sensor to see if it is in the correct range.
At this point it is best to determine if the MAP sensor is defective and if it has no or incorrect output, then replace the MAP 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 P0106 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 P0106 code?
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This article originally appeared on YourMechanic.com as P0106 OBD-II Trouble Code: Manifold Air Pressure (MAP) Barometric Pressure Sensor Electric Circuit Output Range and Performance Problem and was authored by John Nelson.