P0101
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.
On Board Diagnosis Logic
NOTE:
If DTC P0101 is displayed with other DTC, first perform the trouble diagnosis for other DTC.
DTC Confirmation Procedure
1. PRECONDITIONING
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.
GO TO 2.
2. PERFORM DTC CONFIRMATION PROCEDURE
1 Start engine and warm it up to normal operating temperature.
2 Drive the vehicle for at least 5 seconds under the following conditions:
CAUTION:
Always drive vehicle at safe speed.
NOTE:
- The gear must be fixed while driving the vehicle.
- Keep the accelerator pedal as steady as possible during cruising.
3 Check 1st trip DTC.
Is 1st trip DTC detected?
YES
Proceed to "Diagnosis Procedure".
NO
INSPECTION END
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 three ground screws on the body. Refer to [Power Supply and Ground Circuit Check] Power Supply and Ground Circuit Check.
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 harness connector.
2 Turn ignition switch ON.
3 Check voltage between MAF sensor terminal 2 and ground with SDT or tester.
OK or NG
OK
GO TO 6.
NG
GO TO 5.
5. DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors E2, F32
- Harness for open or short between IPDM E/R and mass air flow sensor
- Harness for open or short between mass air flow sensor and ECM
Repair 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.
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.
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
Refer to [P0112, P0113 IAT Sensor] P0112.
OK or NG
OK
GO TO 9.
NG
Replace intake air temperature sensor. Refer to [Air Cleaner and Air Duct: Exploded View] Exploded View.
9. CHECK EVAP CONTROL SYSTEM PRESSURE SENSOR
Refer to [P0451 EVAP Control System Pressure Sensor] P0451.
OK or NG
OK
GO TO 10.
NG
Replace EVAP control system pressure sensor. Refer to [EVAP Canister: Removal and Installation] Service and Repair.
10. CHECK MASS AIR FLOW SENSOR
Refer to "Component Inspection".
OK or NG
OK
GO TO 11.
NG
Replace mass air flow sensor. Refer to [Air Cleaner and Air Duct: Exploded View] Exploded View.
11. CHECK INTERMITTENT INCIDENT
Refer to [Service Information for Electrical Incident: Intermittent Incident] Service Information for Electrical Incident: Intermittent Incident.
INSPECTION END
Component Inspection
Mass Air Flow Sensor
With SDT
1) Reconnect all harness connectors disconnected.
2) Start engine and warm it up to normal operating temperature.
3) Connect SDT and select "Data list" mode.
4) Select "MAS A/F SE-B1" and check indication under the following conditions.
*: Check for linear voltage rise in response to engine being increased to about 4,000 rpm.
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 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 step 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 step 2 to 4 again.
9) If NG, clean or replace mass air flow sensor.
Without SDT
10) Reconnect all harness connectors disconnected.
11) Start engine and warm it up to normal operating temperature.
12) Check voltage between ECM terminal 51 (Mass air flow sensor signal) and ground.
*: Check for linear voltage rise in response to engine being increased to about 4,000 rpm.
13) 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 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 step 2 to 3 again.
If OK, go to next step.
14) Turn ignition switch OFF.
15) Disconnect mass air flow sensor harness connector and reconnect it again.
16) Perform step 2 and 3 again.
17) If NG, clean or replace mass air flow sensor.