P0101

DTC P0101 MAF SENSOR





Component Description





The mass air flow sensor (1) is placed in the stream of intake air. It measures the intake flow rate by measuring a part of the entire intake flow. The mass air flow sensor controls the temperature of the hot wire to a certain amount. The heat generated by the hot wire is reduced as the intake air flows around it. The greater air flow, the greater the heat loss.
Therefore, the electric current supplied to hot wire is changed to maintain the temperature of the hot wire as air flow increases. The
ECM detects the air flow by means of this current change.




CONSULT-III Reference Value in Data Monitor Mode
Specification data are reference values.









On Board Diagnosis Logic









DTC Confirmation Procedure
Perform PROCEDURE FOR MALFUNCTION A first.
If DTC cannot be confirmed, perform PROCEDURE FOR MALFUNCTION B.

NOTE:
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure before conducting the next test.
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.

PROCEDURE FOR MALFUNCTION A

NOTE:
If engine will not start or stops soon, wait at least 10 seconds with engine stopped (Ignition switch ON) instead of running engine at idle speed.
1. Start engine and warm it up to normal operating temperature.
2. Run engine for at least 10 seconds at idle speed.
3. Check 1st trip DTC.
4. If 1st trip DTC is detected, go to P0101.

PROCEDURE FOR MALFUNCTION B

CAUTION:
Always drive vehicle at a safe speed.

With CONSULT-III
1. Start engine and warm it up to normal operating temperature.
If engine cannot be started, go to P0101.





2. Check the voltage of "MAS A/F SE-B1" in "DATA MONITOR" mode with CONSULT-III.
3. Increases engine speed to approximately 4,000 rpm.
4. Monitor the linear voltage rise in response to engine speed increases.
If NG, go to P0101.
If OK, go to the following step.
5. Maintain the following conditions for at least 10 consecutive seconds.





6. Check 1st trip DTC.
7. If 1st trip DTC is detected, go to P0101.




Overall Function Check

PROCEDURE FOR MALFUNCTION B
Use this procedure to check the overall function of the mass air flow sensor circuit. During this check, a 1st trip
DTC might not be confirmed.

With GST
1. Start engine and warm it up to normal operating temperature.
2. Select Service $01 with GST.





3. Check the mass air flow sensor signal with Service $01.
4. Check for linear mass air flow sensor signal value rise in response to increases to approximately 4,000 rpm in engine speed.
5. If NG, go to P0101.




Wiring Diagram





Specification data are reference values and are measured between each terminal and ground.

CAUTION:
Never use ECM ground terminals when measuring input/output voltage. Doing so may result in damage to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.









Diagnosis Procedure
1.INSPECTION START
Which malfunction (A or B) is duplicated?
A or B
A - GO TO 3.
B - GO TO 2.
2.CHECK INTAKE SYSTEM
Check the following for connection.
- Air duct
- Vacuum hoses
- Intake air passage between air duct and intake manifold
OK or NG
OK - GO TO 3.
NG - Reconnect the parts.
3.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten ground screws on the body. Power Supply and Ground Circuit.










OK or NG
OK - GO TO 4.
NG - Repair or replace ground connections.
4.CHECK MAF SENSOR POWER SUPPLY CIRCUIT





1. Disconnect mass air flow (MAF) sensor (1) harness connector.
2. Turn ignition switch ON.





3. Check voltage between MAF sensor terminal 2 and ground with
CONSULT-III or tester.

Voltage: Battery voltage

OK or NG
OK - GO TO 6.
NG - GO TO 5.
5.DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors E108, M15
- Harness connectors M72, F102
- Harness for open or short between mass air flow sensor and ECM
- Harness for open or short between mass air flow sensor and IPDM E/R
- Repair open circuit or short to ground or short to power in harness or connectors.
6.CHECK MAF SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between MAF sensor terminal 3 and ECM terminal 67. Refer to Wiring Diagram.

Continuity should exist.

4. Also check harness for short to ground and short to power.
OK or NG
OK - GO TO 7.
NG - Repair open circuit or short to ground or short to power in harness or connectors.
7.CHECK MAF SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between MAF sensor terminal 4 and ECM terminal 51. Refer to Wiring Diagram.

Continuity should exist.

2. Also check harness for short to ground and short to power.
OK or NG
OK - GO TO 8.
NG - Repair open circuit or short to ground or short to power in harness or connectors.
8.CHECK INTAKE AIR TEMPERATURE SENSOR
P0112.
OK or NG
OK - GO TO 9.
NG - Replace intake air temperature sensor.
9.CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR
P0451.
OK or NG
OK - GO TO 10.
NG - Replace EVAP control system pressure sensor.
10.CHECK MASS AIR FLOW SENSOR
P0101.
OK or NG
OK - GO TO 11.
NG - Replace mass air flow sensor.
11.CHECK INTERMITTENT INCIDENT
Diagnosis Procedure.
- INSPECTION END




Component Inspection

MASS AIR FLOW SENSOR

With CONSULT-III
1. Reconnect all harness connectors disconnected.
2. Start engine and warm it up to normal operating temperature.
3. Connect CONSULT-III and select "DATA MONITOR" mode.
4. Select "MAS A/F SE-B1" and check indication under the following conditions.





5. If the voltage is out of specification, proceed the following.
a. Check for the cause of uneven air flow through mass air flow sensor. Refer to the following.
- Crushed air ducts
- Malfunctioning seal of air cleaner element
- Uneven dirt of air cleaner element
- Improper specification of intake air system parts b. If NG, repair or replace malfunctioning part and perform steps 2 to 4 again.
If OK, go to next step.
6. Turn ignition switch OFF.
7. Disconnect mass air flow sensor harness connector and reconnect it again.
8. Perform steps 2 to 4 again.
9. If NG, clean or replace mass air flow sensor.

Without CONSULT-III
1. Reconnect all harness connectors disconnected.
2. Start engine and warm it up to normal operating temperature.





3. Check voltage between ECM terminal 51 (Mass air flow sensor signal) and ground.





4. If the voltage is out of specification, proceed the following.
a. Check for the cause of uneven air flow through mass air flow sensor. Refer to the following.
- Crushed air ducts
- Malfunctioning seal of air cleaner element
- Uneven dirt of air cleaner element
- Improper specification of intake air system parts b. If NG, repair or replace malfunctioning part and perform steps 2 and 3 again.
If OK, go to next step.
5. Turn ignition switch OFF.
6. Disconnect mass air flow sensor harness connector and reconnect it again.
7. Perform steps 2 and 3 again.
8. If NG, clean or replace mass air flow sensor.




Removal and Installation

MASS AIR FLOW SENSOR
Component.