F150 2004 5.4 maf sensor reference values - 2004 Ford F150

DTC P0101
The mass air flow (MAF) sensor is an air flow meter that measures the amount of air entering the engine. The powertrain control module (PCM) uses the MAF sensor signal in order to provide the correct fuel delivery for a wide range of engine speeds and loads. A small quantity of air entering the engine indicates deceleration or idle. A large quantity of air entering the engine indicates an acceleration or high load situation. The MAF sensor has an ignition 1 voltage circuit, a ground circuit and a signal circuit. The PCM applies a voltage to the sensor on the signal circuit. The sensor uses the voltage in order to produce a frequency based on inlet air flow through the sensor bore. The PCM uses the barometric pressure, air density, manifold pressure, throttle position, and the engine RPM in order to calculate a predicted MAF value. The PCM compares the actual MAF sensor signal to the predicted MAF value in order to determine if the signal is stuck based on a lack of variation, or is too low or too high for a given operating condition. DTC P0101 will set if the actual MAF sensor signal is not within a predetermined range of the calculated MAF value.

Diagnostic Aids
Inspect for the following conditions:
• A misrouted harness--Inspect the harness of the MAF sensor in order to verify that the harness is not routed too close to the following components:
- The ignition cassettes
- Any solenoids
- Any relays
- Any motors
• The throttle plate sticking or excessive deposits on the throttle plate or in the throttle bore.
• Any unmetered air that enters the engine may cause this DTC to set. Verify that the oil dipstick is fully seated and the oil filler cap is secure.
• The MAF display should increase from 4-7 g/s at idle to 190 g/s or more at the 1-2 shift during a wide open acceleration. If not, inspect for a restriction.
• The barometric pressure that is used in order to calculate the predicted mass air flow value is based on the MAP sensor reading at key ON. A skewed MAP sensor will cause the calculated Mass Air Flow value to be inaccurate. The value shown for the MAP sensor display varies with the altitude. With the ignition ON and the engine OFF, 103 kPa is the approximate value displayed at or near sea level. The value decreases by approximately 3.0 kPa for every 1,000 feet of altitude.

DTC P0101
Circuit Description
The mass air flow (MAF) sensor is an air flow meter that measures the amount of air entering the engine. The powertrain control module (PCM) uses the MAF sensor signal to provide the correct fuel delivery for all engine speeds and loads. A small quantity of air entering the engine indicates a deceleration or idle condition. A large quantity of air entering the engine indicates an acceleration or high load condition. The MAF sensor has the following circuits:
• An ignition 1 voltage circuit
• A ground circuit
• A signal circuit
The PCM applies a voltage to the sensor on the signal circuit. The sensor uses the voltage to produce a frequency based on the inlet air flow through the sensor bore. The frequency varies within a range of near 2,000 Hertz at idle to near 10,000 Hertz at maximum engine load. The PCM uses the following sensor inputs to calculate a predicted MAF value:
• The barometric pressure (BARO) at key ON
• The manifold absolute pressure (MAP) sensor
• The intake air temperature (IAT) sensor
• The engine coolant temperature (ECT) sensor
• The throttle position (TP) sensor
• The engine speed (RPM)
The PCM compares the actual MAF sensor frequency signal to the predicted MAF value. This comparison will determine if the signal is stuck based on a lack of variation, or is too low or too high for a given operating condition. If the PCM detects the actual MAF sensor frequency signal is not within a predetermined range of the calculated MAF value DTC P0101 sets.

Important:: The Altitude vs. Barometric Pressure table indicates a pressure range for a given altitude under normal weather conditions. Weather conditions consisting of very low or very high pressure and/or temperature may cause a reading to be slightly out of range.
Turn ON the ignition, with the engine OFF.
Observe the MAP Sensor kPa parameter with a scan tool.
The manifold absolute pressure (MAP) sensor pressure should be within the specified range for your altitude. Refer to Altitude Versus Barometric Pressure .
Is the MAP sensor pressure within the specified range as indicated on the Altitude vs Barometric Pressure table?

Generally, PO101 is a code for a Mass Air Flow sensor problem. I don't know if your car has one.
The code means the computer does not see the amount of air coming into the intake that it thinks should be happening.
Sometimes it is a failed sensor, sometimes it is a leaking hose or restricted air filter.

P0108 - (Manifold Absolute Pressure/Barometric Pressure Circuit High Input
The MAP (Manifold Absolute Pressure) sensor measures engine manifold negative air pressure. It's usually a three wire sensor: a ground wire, a 5 volt reference wire from the PCM (Powertrain Control Module) to the MAP sensor, and a signal wire that informs the PCM of the MAP sensor voltage reading as it changes. The higher the engine vacuum, the lower the voltage reading. The voltage should range between about 1 volt (at idle) to about 5 volts (WOT wide open throttle).

If the PCM sees the voltage reading from the MAP sensor is greater than 5 Volts, or if the voltage reading is higher than what the PCM considers normal under certain circumstances, a P0108 DTC will set.

Symptoms of a P0108 DTC code may include:
* MIL (Malfunction Indicator Lamp) will likely be on
* Engine may run poorly
* Engine may not run at all
* Fuel mileage may decrease
* Presence of black smoke at exhaust

Potential causes of a P0108 code:
* Bad MAP sensor
* Leak in vacuum supply line to MAP sensor
* Engine vacuum leak
* Short on signal wire to PCM
* Short on reference voltage wire from PCM
* Open in ground circuit to MAP
* Worn engine causing low vacuum

Possible Solutions:
A good way to diagnose if the MAP sensor is to blame would be to compare the KOEO (key on engine off) MAP sensor reading on a scan tool with the Barometric pressure reading. They should be the same because they both measure atmospheric pressure.

If the MAP reading is greater than 0.5 volt off of the BARO reading, then replacing the MAP sensor would likely fix the problem. Otherwise, start the engine and observe the MAP reading at idle. It should normally be about 1.5 volts (varies according to altitude).

a. If it is, the problem is likely intermittent. Check all the vacuum hoses for damage and replace as necessary. You can also try wiggle testing the harness and connector to reproduce the problem.
b. If the scan tool MAP reading is more than 4.5 volts, check the actual engine vacuum reading with the engine running. If it is less than 15 or 16 in. Hg, then the PCM is probably not seeing enough vacuum (due to a worn engine, perhaps) for a given operating condition (which causes a higher than normal voltage signal to the PCM) and setting the code. Repair the engine vacuum problem and retest.
c. But, if the actual engine vacuum reading is 16 in. Hg or more, then unplug the MAP sensor. The scan tool MAP reading should indicate that there is no voltage present. Check that the ground from the PCM is intact and also that the MAP sensor connector and terminals are tight. If the connection is good, then replace the map sensor.
d. However if, with KOEO, & the MAP sensor unplugged, the scan tool shows a voltage reading, then there may be a short in the harness to the MAP sensor. Turn the ignition off. At the PCM unplug connector and remove the MAP signal wire from the connector. Re-attach the PCM connector and see if with KOEO, the scan tool MAP reading shows voltage. If it still does, replace the PCM. If not, check for voltage on the signal wire you just removed from the PCM. If there is voltage on the signal wire, find the short in the harness and repair.


P0104 - Mass Air Flow (MAF) Circuit Intermittent
Basically this means that there is a problem with the Mass Air Flow High (MAF) sensor or circuit. A more technical description would be that the MAF is producing incorrect air flow readings. Other MAF sensor circuit DTC trouble codes are P0100, P0101, P0102, and P0103.

Symptoms: You will likely not notice any serious drivability problems, although there may be symptoms such as a general decrease in power or sluggishness.

Causes: A code P0104 may mean that one or more of the following has happened:
* The mass air flow (MAF) circuit is incomplete (broken / frayed wire, etc.)
* There is an air leak in the intake system

Possible Solutions: The simplest thing to do is to reset the code and see if it comes back. Then start with the cheapest, easiest repair procedures:
* Verify that the Mass Air Flow Sensor wiring is connected properly and that there are no broken / frayed wires.
* Inspect for any air leaks near the MAF sensor.
* Check the voltage of the MAF sensor (refer to a repair manual for vehicle specific information)
* Replace the MAF sensor.



P0102 - Mass Air Flow (MAF) Circuit Low Input
Basically this means that there is a problem with the Mass Air Flow (MAF) sensor or circuit. A more technical description would be that the MAF circuit had lower than expected voltage (air flow). Other MAF sensor circuit DTC trouble codes are P0100, P0101, P0103, and P0104.
Symptoms: You will likely not notice any serious drivability problems, although there may be symptoms such as a general decrease in power or sluggishness.

Causes: A code P0102 may mean that one or more of the following has happened:
* The MAF may be disconnected, or a wiring connection may be bad
* The MAF may be dirty or otherwise contaminated (Note: if you use a reusable oiled air filter, be careful not to apply too much oil or that can contaminate the MAF).
* The MAF sensor may be faulty
* The vehicle computer may be faulty (very rare)

Possible Solutions: The simplest thing to do is to reset the code and see if it comes back. Then start with the cheapest, easiest repair procedures:
* Verify that the Mass Air Flow Sensor wiring is connected properly and that there are no broken / frayed wires.
* Inspect for any air leaks near the MAF sensor.
* Take the MAF out and clean it using a spray cleaner such as brake cleaner or electrical contact cleaner. Be gentle with the sensor.
* Check the voltage of the MAF sensor (refer to a repair manual for vehicle specific information)
* Replace the MAF sensor.




P0101 - Mass Air Flow (MAF) Circuit Range/Performance Problem
Basically this means that there is a problem with the Mass Air Flow (MAF) sensor or circuit. The PCM detects that the actual MAF sensor frequency signal is not within a predetermined range of the calculated MAF value for more than 4.0 seconds. Other MAF sensor circuit DTC trouble codes are P0100, P0102, P0103, and P0104.

Symptoms: You will likely not notice any serious drivability problems, although there may be symptoms.

Possible Solutions: The simplest thing to do is to reset the code and see if it comes back. Then start with the cheapest, easiest repair procedures:
* Inspect for the following conditions:
An incorrectly routed harness--Inspect the harness of the MAF sensor in order to verify that it is not routed too close to the following components:
- The secondary ignition wires or coils
- Any solenoids
- Any relays
- Any motors
* A low minimum air rate through the sensor bore may cause this DTC to set at idle or during deceleration. Inspect for any vacuum leaks downstream of the MAF sensor.
* A wide open throttle (WOT) acceleration from a stop should cause the MAF sensor g/s display on the scan tool to increase rapidly. This increase should be from 6-12 g/s at idle to 230 g/s or more at the time of the 1-2 shift. If the increase is not observed, inspect for a restriction in the induction system or the exhaust system.
* The barometric pressure (BARO) that is used in order to calculate the predicted MAF value is initially based on the MAP sensor at key ON.
* When the engine is running the MAP sensor value is continually updated near WOT. A skewed MAP sensor will cause the calculated MAF value to be inaccurate. The value shown for the MAP sensor display varies with the altitude. With the ignition ON and the engine OFF, 103 kPa is the approximate value near sea level. This value will decrease by approximately 3 kPa for every 305 meters (1,000 feet) of altitude.
* A high resistance on the ground circuit of the MAP sensor can cause this DTC to set.
* Any loss of vacuum to the MAP sensor can cause this DTC to set.

If you suspect the condition may be related to aftermarket accessories, refer to Checking Aftermarket Accessories in Wiring Systems. Here as an aid in resolving your P0101 trouble code (DTC)...

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P0101 - Mass Air Flow (MAF) Circuit Range/Performance Problem
Basically this means that there is a problem with the Mass Air Flow (MAF) sensor or circuit. The PCM detects that the actual MAF sensor frequency signal is not within a predetermined range of the calculated MAF value for more than 4.0 seconds. Other MAF sensor circuit DTC trouble codes are P0100, P0102, P0103, and P0104.

Symptoms: You will likely not notice any serious drivability problems, although there may be symptoms.

Possible Solutions: The simplest thing to do is to reset the code and see if it comes back. Then start with the cheapest, easiest repair procedures:
* Inspect for the following conditions:
An incorrectly routed harness--Inspect the harness of the MAF sensor in order to verify that it is not routed too close to the following components:
- The secondary ignition wires or coils
- Any solenoids
- Any relays
- Any motors
* A low minimum air rate through the sensor bore may cause this DTC to set at idle or during deceleration. Inspect for any vacuum leaks downstream of the MAF sensor.
* A wide open throttle (WOT) acceleration from a stop should cause the MAF sensor g/s display on the scan tool to increase rapidly. This increase should be from 6-12 g/s at idle to 230 g/s or more at the time of the 1-2 shift. If the increase is not observed, inspect for a restriction in the induction system or the exhaust system.
* The barometric pressure (BARO) that is used in order to calculate the predicted MAF value is initially based on the MAP sensor at key ON.
* When the engine is running the MAP sensor value is continually updated near WOT. A skewed MAP sensor will cause the calculated MAF value to be inaccurate. The value shown for the MAP sensor display varies with the altitude. With the ignition ON and the engine OFF, 103 kPa is the approximate value near sea level. This value will decrease by approximately 3 kPa for every 305 meters (1,000 feet) of altitude.
* A high resistance on the ground circuit of the MAP sensor can cause this DTC to set.
* Any loss of vacuum to the MAP sensor can cause this DTC to set.

If you suspect the condition may be related to aftermarket accessories, refer to Checking Aftermarket Accessories in Wiring Systems.

Check this it is here as an aid in resolving your P0101 trouble code (DTC)...

P0401 - Insufficient EGR Flow
EGR stands for Exhaust Gas Recirculation. It is part of the vehicle emmissions system, and is used to reduce combustion temperature and pressure to control Oxides of Nitrogen. There are generally three parts to the EGR system: the EGR valve, an actuator solenoid, and a differential pressure sensor EGR (DPFE). These things work together to deliver the correct amount of recirculation based on engine temperature, load, etc. The P0401 code means that OBD detected an insufficient amount of EGR.

Symptoms: You may notice drivability problems such as pinging (a.k.a. pre-ignition knock) when the engine is under load or the vehicle is at higher speeds. There may also be other symptoms.

Causes: A code P0401 most likely means one or more of the following has happened:
* The DPFE (differential pressure feedback EGR) sensor is faulty and needs to be replaced
* There is a blockage in the EGR (tube), most likely carbon buildup
* The EGR valve is faulty
* The EGR valve may not be opening due to a lack of vaccuum

Possible Solutions: In fixing this code, it is quite common for people to just replace the EGR valve only to have the OBD code return. The EGR valve is not always the culprit.
* Use a vacuum pump and pull the EGR valve open while monitoring engine RPM's & DPFE voltage. There should be a noticable difference in RPM's with the EGR open
* Clean out the EGR valve and/or tubing to remove deposits
* Check the voltage at the DPFE, compare to specified values (refer to a repair manual for your specific model)
* Replace the DPFE sensor (with a good quality / OEM one)
* Replace the EGR valve


Keep us updated.

I wouldn't remove the sensor. Get yourself a can of electrical parts cleaner. They have it at most car parts chains. Then, just take off the air filter and look inside the inlet. The sensor should be right there. Don't touch it. Just give it a couple of good sprays. More if it looks dirty. I have pasted info below on you system that I copied from autozone.com. Let us know if you have more questions, and thanks for using FixYa!

Operation The Mass Air Flow (MAF) sensor is an air flow meter that measures the amount of air entering the engine. The Electronic Control Module (ECM) uses the MAF sensor signal to provide the correct fuel delivery for all engine speeds and loads. A small quantity of air entering the engine indicates a deceleration or idle condition. A large quantity of air entering the engine indicates an acceleration or high load condition. The MAF sensor has the following circuits:



An ignition 1 voltage circuit A ground circuit A MAF sensor signal circuit An IAT sensor signal circuit A low reference circuit

The ECM applies 5 volts to the MAF sensor on the MAF sensor signal circuit. The sensor uses the voltage to produce a frequency based on the inlet air flow through the sensor bore. The frequency varies in a range of near 1,700 Hertz at idle to near 9,500 Hertz at maximum engine load.

Removal & Installation

1. Before servicing the vehicle, refer to the Precautions Section.
2. Disconnect the negative battery cable.
3. Remove the air pump assembly.
4. Remove the 2 bracket mounting bolts.
5. Remove the bracket assembly.
6. Disconnect the electrical connector to the Mass Air Flow (MAF) sensor.
7. Twist the MAF sensor sideways and remove it from the bracket.
8. Remove the rubber mounting.
   
   

   Fig. Remove the 2 bracket mounting bolts
   

To install:

1. Install the rubber mounting to the MAF sensor.
2. Twist the MAF sensor sideways and install it into the bracket.
3. Connect the electrical connector to MAF sensor.
4. Install the bracket assembly.
5. Install the 2 bracket mounting bolts.
6. Install the air pump assembly.
7. Connect the negative battery cable.

Testing

1. Verify the integrity of the air induction system by inspecting for the following conditions:
   
   Damaged components Loose or improper installation An air flow restriction Any vacuum leak Water intrusion
   
2. With the engine running, observe the scan tool Mass Air Flow (MAF) sensor parameter. The reading should be between 1,700-3,200 Hz depending on the Engine Coolant Temperature (ECT).
3. Verify that any electrical aftermarket devices are properly connected and grounded.
4. Inspect the harness of the MAF sensor to verify that it is not routed too close to the following components:
   
   Any aftermarket accessories The secondary ignition wires or coils Any solenoids Any relays Any motors
   
5. A low minimum air rate through the sensor bore at idle or during deceleration may cause a DTC to set. Inspect for the following conditions:
   
   Any deposits on the throttle plate or in the throttle bore Any vacuum leak downstream of the MAF sensor
   
6. Inspect for any contamination or debris on the sensing elements of the MAF sensor.
7. Inspect the air induction system for any water intrusion. Any water that reaches the MAF sensor will skew the sensor and may cause a DTC to set.
8. A Wide Open Throttle (WOT) acceleration from a stop should cause the MAF sensor parameter on the scan tool to increase rapidly. This increase should be from 3-10 g/s at idle to 150 g/s or more at the time of the 1 to 2 shift of the transmission. If the increase is not observed, inspect for a restriction in the induction system or the exhaust system.
9. Inspect for a skewed or stuck Engine Coolant Temperature (ECT) sensor.
10. Test for a high resistance of 15 ohms or more on the ignition 1 voltage circuit. This may cause a DTC to set. A high resistance may also cause a drivability concern before a DTC sets.

The Barometric Pressure (BARO) sensor that is used in order to calculate the predicted mass air flow value is initially based on the Manifold Absolute Pressure (MAP) sensor at key ON. When the engine is running, the BARO value is continually updated near WOT. A skewed MAP sensor will cause the calculated mass air flow value to be inaccurate and may result in a no start condition. The value shown for the MAP sensor parameter varies with the altitude. With the ignition ON and the engine OFF, 101 kPa is the approximate value near sea level. This value will decrease by approximately 3 kPa for every 1,000 feet (305 meters) of altitude.

P0106 - MAP/Barometric Pressure Circuit Range/Performance Problem

The Powertrain Control Module (PCM) uses the Manifold Absolute Pressure Sensor (MAP) to monitor engine load. (NOTE: Some vehicles have a Barometric Pressure (BARO) sensor that is integral to the Mass Air Flow (MAF) sensor and do not have a MAP sensor. Other vehicles have a MAF/BARO and a redundant MAP sensor where the MAP sensor functions as a backup input in case of MAF failure.) The PCM supplies a 5 Volt reference signal to the MAP sensor. Usually the PCM also supplies a ground circuit to the MAP sensor as well. As the manifold pressure changes with load, the MAP sensor input informs the PCM. At idle the voltage should be 1 to 1.5 Volts and approximately 4.5 Volts at Wide Open Throttle (WOT). The PCM looks for any change in manifold pressure to be preceded by a change in engine load in the form of changes in throttle angle, engine speed, or Exhaust Gas Recirculation (EGR) flow. If the PCM doesn't see any of these factors change while detecting a rapid change in MAP value, it will set a P0106.

Potential Symptoms: The following could be symptomatic of a P0106:
* Engine runs rough
* Black smoke at tailpipe
* Engine will not idle
* Poor fuel economy
* Engine misses at speed

Causes: A P0106 could be caused by:
* Bad MAP sensor
* Water/dirt intrusion affecting MAP sensor connector
* Intermittent open in the reference, ground, or signal wire for the MAP sensor
* Intermittent short in the reference, ground, or signal wire for the MAP sensor
* Ground problem due to corrosion causing intermittent signal problem
* A break in the flexible air intake duct between the MAF and the intake manifold
* Bad PCM (do not assume the PCM is bad until you've exhausted all other possibilities)

Possible Solutions: Using a scan tool, watch the MAP sensor value with the key on, engine off. Compare the BARO reading with the MAP reading. They should be roughly equal. The voltage for the MAP sensor should read approx. 4.5 volts. Now start the engine and look for a significant drop in the MAP sensor voltage indicating the MAP sensor is working.

If the MAP reading doesn't change perform the following:
1. With the Key on, engine off, disconnect the vacuum hose from the MAP sensor. Using a vacuum pump, pull 20 in. of vacuum on the MAP sensor. Does the voltage drop? It should. If it doesn't inspect the MAP sensor vacuum port and vacuum hose to manifold for a restriction of some kind. Repair or replace as necessary.
2. If there are no restrictions, and the value doesn't change with vacuum, then perform the following: with the Key on and engine off and the MAP sensor unplugged, check for 5 Volts at the reference wire to the MAP sensor connector with a Digital Voltmeter. If there is none, check for reference voltage at the PCM connector. If the reference voltage is present at the PCM connector but not the MAP connector, check for open or short in the reference wire between MAP and PCM and retest.
3. If reference voltage is present, then check for existing ground at the MAP sensor connector. If it isn't present then repair open/short in the ground circuit.
4. If ground is present, then replace MAP sensor.

Other MAP sensor trouble codes include P0105, P0106, P0107, P0108 and P0109.

I hope this helps to solve it (remember to rate this answer).

P0101 - Mass Air Flow (MAF) Circuit Range/Performance Problem

Basically this means that there is a problem with the Mass Air Flow (MAF) sensor or circuit. The PCM detects that the actual MAF sensor frequency signal is not within a predetermined range of the calculated MAF value for more than 4.0 seconds. Other MAF sensor circuit DTC trouble codes are P0100, P0102, P0103, and P0104.

Symptoms: You will likely not notice any serious drivability problems, although there may be symptoms.

Possible Solutions:
The simplest thing to do is to reset the code and see if it comes back. Then start with the cheapest, easiest repair procedures:
* Inspect for the following conditions:
An incorrectly routed harness--Inspect the harness of the MAF sensor in order to verify that it is not routed too close to the following components:
- The secondary ignition wires or coils
- Any solenoids
- Any relays
- Any motors
* A low minimum air rate through the sensor bore may cause this DTC to set at idle or during deceleration. Inspect for any vacuum leaks downstream of the MAF sensor.
* A wide open throttle (WOT) acceleration from a stop should cause the MAF sensor g/s display on the scan tool to increase rapidly. This increase should be from 6-12 g/s at idle to 230 g/s or more at the time of the 1-2 shift. If the increase is not observed, inspect for a restriction in the induction system or the exhaust system.
* The barometric pressure (BARO) that is used in order to calculate the predicted MAF value is initially based on the MAP sensor at key ON.
* When the engine is running the MAP sensor value is continually updated near WOT. A skewed MAP sensor will cause the calculated MAF value to be inaccurate. The value shown for the MAP sensor display varies with the altitude. With the ignition ON and the engine OFF, 103 kPa is the approximate value near sea level. This value will decrease by approximately 3 kPa for every 305 meters (1,000 feet) of altitude.
* A high resistance on the ground circuit of the MAP sensor can cause this DTC to set.
* Any loss of vacuum to the MAP sensor can cause this DTC to set.

Hope this helps (remember rated this).

asically this means that there is a problem with the Mass Air Flow (MAF) sensor or circuit. The PCM detects that the actual MAF sensor frequency signal is not within a predetermined range of the calculated MAF value for more than 4.0 seconds. The simplest thing to do is to reset the code and see if it comes back. Then start with the cheapest, easiest repair procedures:

• Inspect for the following conditions:
  An incorrectly routed harness--Inspect the harness of the MAF sensor in order to verify that it is not routed too close to the following components:
  - The secondary ignition wires or coils
  - Any solenoids
  - Any relays
  - Any motors
• A low minimum air rate through the sensor bore may cause this DTC to set at idle or during deceleration. Inspect for any vacuum leaks downstream of the MAF sensor.
• A wide open throttle (WOT) acceleration from a stop should cause the MAF sensor g/s display on the scan tool to increase rapidly. This increase should be from 6-12 g/s at idle to 230 g/s or more at the time of the 1-2 shift. If the increase is not observed, inspect for a restriction in the induction system or the exhaust system.
• The barometric pressure (BARO) that is used in order to calculate the predicted MAF value is initially based on the MAP sensor at key ON.
• When the engine is running the MAP sensor value is continually updated near WOT. A skewed MAP sensor will cause the calculated MAF value to be inaccurate. The value shown for the MAP sensor display varies with the altitude. With the ignition ON and the engine OFF, 103 kPa is the approximate value near sea level. This value will decrease by approximately 3 kPa for every 305 meters (1,000 feet) of altitude.
• A high resistance on the ground circuit of the MAP sensor can cause this DTC to set.
• Any loss of vacuum to the MAP sensor can cause this DTC to set.

If you suspect the condition may be related to aftermarket accessories, refer to Checking Aftermarket Accessories in Wiring Systems.

P0101 shows possible failing PCV valve as well as the MAF sensor. If neither of these fixes the problem, it's a possible PCM issue.