P0101
P0101 MAF SensorComponent 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
P0101:
DTC Confirmation Procedure
Perform PROCEDURE FOR MALFUNCTION A first.
If the DTC cannot be confirmed, perform PROCEDURE FOR MALFUNCTION B.
NOTE: If DTC Confirmation Procedure has been previously conducted, always perform the following before conducting the next step.
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. 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.
With SDT
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 MAF Sensor].
With GST
Follow the procedure "With SDT" above.
PROCEDURE FOR MALFUNCTION B
CAUTION: Always drive vehicle at a safe speed.
With SDT
1. Start engine and warm it up to normal operating temperature.
If engine cannot be started, go to [P0101 MAF Sensor].
2. Select "Data list" mode with SDT.
3. Check the voltage of "MAS A/F SE-B1" with "Data list".
4. Increases engine speed to about 4,000 rpm.
5. Monitor the linear voltage rise in response to engine speed increases.
If NG, go to [P0101 MAF Sensor].
If OK, go to following step.
6. Maintain the following conditions for at least 10 consecutive seconds.
7. Check 1st trip DTC.
8. If 1st trip DTC is detected, go to [P0101 MAF Sensor].
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 about 4,000 rpm in engine speed.
5. If NG, go to [P0101 MAF Sensor].
Diagnosis Procedure
Step 1-3:
Step 4-6:
Step 7-11:
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.
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
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 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.
5. Turn ignition switch OFF.
6. Disconnect mass air flow sensor harness connector and reconnect it again.
7. Perform step 2 and 3 again.
8. If NG, clean or replace mass air flow sensor.