P0106 - Manifold Absolute Pressure/Barometric Pressure Circuit Range/Performance Problem

The code P0106 - Manifold Absolute Pressure/Barometric Pressure Circuit Range/Performance Problem refers either to the Manifold Absolute Pressure sensor (MAP) sensor or to the Barometric Pressure sensor (BARO) circuit depending on a car.

MAP sensor
Honda MAP sensor.

The MAP sensor measures the absolute pressure inside the engine intake manifold which is directly related to the engine load. The accompanied symptoms for a MAP sensor fault could include lack of power, rough idle, as well as too high or too low idle speed.

What can cause the code P0106:
- clogged a cracked vacuum line to the sensor
- electrical problems with the wiring, connector or the ECM power supply
- faulty MAP/BARO sensor
- dirty throttle body
- problems with the EGR system
- bad mass airflow sensor (MAF)
- engine mechanical problems
- blocked exhaust or catalytic converter

Examples:
A Mazda technical service bulletin (TSB) describes a problem with the corrosion at the MAP sensor causing the code P0106 (MAP sensor malfunction) in 4-cylinder models of some 2004-2006 Mazda 3, 2006 Mazda 5, 2006 Mazda MX-5 and 2003-2006 Mazda 6. The TSB recommends replacing the MAP sensor with an updated part.
A GM TSB describes a problem with some 2006-2009 GM trucks where the condensation may freeze inside the MAP sensor in cold weather causing the code P0106. The TSB recommends to modify a MAP sensor.

How the MAP/BARO sensor works:

MAP sensor
MAP sensor.

A typical MAP or BARO sensor is a 3-wire sensor and is connected to the ECM. One wire receives the +5 Volts reference voltage from the ECM, another wire is connected to the ground. The third wire is a signal wire. The MAP sensor signal voltage changes between about 1 Volt and 4.9 Volts depending on the pressure.

If it's a MAP sensor, the signal voltage with the ignition key ON, engine OFF (KOEO) should be around 4-4.9 Volts. With the engine running at idle, the signal voltage should drop to around 1-2 Volts; when the engine is accelerated sharply, the signal should change to around 4-4.5 Volts.

How to check the MAP sensor:
With the ignition ON, check the +5 Volts reference voltage with the voltmeter and the ground at the sensor. Next, check the signal voltage and see what it reads with the ignition key ON, engine OFF (KOEO) and if it changes when the engine is started. If you have a scan tool, select Data Monitor mode and check the MAP sensor reading with ignition ON, engine OFF. The MAP reading should be close to that of BARO sensor, as with the engine OFF, the pressure inside the intake manifold is equal to the atmospheric pressure.

How the MAP sensor works:
The barometric pressure sensor (BARO) measures the atmospheric pressure that varies with altitude. The engine computer (ECM) uses the signal from the MAP/BARO sensor to adjust the amount of fuel injected into the engine. In some cars the ECM could use the signal from the MAP sensor to check the operation of the EGR system, as well as to check rationality of other sensors.
If there are other trouble codes present along with the P0106, they should be looked at first, as the code P0106 could be set due to other faults.

How to check the MAP sensor:

MAP sensor readings with engine OFF
MAP sensor readings with engine OFF.

Using a voltmeter, check the +5 Volts reference voltage and the ground at the sensor. Next, apply the vacuum and see if the reading changes. With a scan tool, check the sensor reading with the ignition on, engine off (KOEO). The reading should be close to barometric pressure, see the photo. Start the engine and check the reading again. At idle it should be around 15-20 inches Hg

Q: 2000 Mazda Protege with 126K, code P0106?

A: In Mazda Protege, the code P0106 means EGR Boost Sensor Circuit Malfunction. It's still the same three-wire sensor that can be checked as mentioned above. In Mazda, the EGR Boost Sensor is connected through the EGR boost sensor solenoid that also could be defective. Another common issue is the vacuum lines could be plugged with carbon. The EGR valve itself could be inoperative or plugged with carbon.

Q: 2006 Chevrolet Aveo, code P0106?

A: The code P0106 is for the MAP sensor, which is mounted on the intake manifold. See if the vacuum line to the sensor is not broken and check the voltage at the sensor. The sensor itself could go bad; it's not uncommon.