Dtc P0101 Mass Air Flow Circuit Range / Performance Problem

Engine Hybrid System. Yaris. Ncp93, 131
1Nz-Fe Engine Control. Yaris. Ncp93, 131

DESCRIPTION

MONITOR DESCRIPTION

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

CONFIRMATION DRIVING PATTERN

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0101)

CHECK INTAKE SYSTEM

CHECK PCV HOSE CONNECTIONS

DTC P0101 Mass Air Flow Circuit Range / Performance Problem


DESCRIPTION

Refer to DTC P0100 (YARIS_NCP93 RM000000U5B0ITX_01.html).

DTC No.
DTC Detection Condition
Trouble Area
P0101
Conditions (a), (b), (c), (d) and (e) continue for more than 10 seconds (2 trip detection logic):
(a) Engine running
(b) Engine coolant temperature 70°C (158°F) or higher
(c) Throttle Position (TP) sensor voltage 0.24 to 2 V
(d) Average engine load value ratio less than 0.85, or more than 1.15 (varies with estimated engine load)
Average engine load value ratio = Average engine load based on MAF meter output / Average engine load estimated from driving conditions
(e) Average air-fuel ratio less than -20%, or more than 20%
  1. Mass Air Flow (MAF) meter
  2. Intake system
  3. PCV hose connections

MONITOR DESCRIPTION

The MAF meter is a sensor that measures the amount of air flowing through the throttle valve. The ECM uses this information to determine the fuel injection time and to provide an appropriate air-fuel ratio. Inside the MAF meter, there is a heated platinum wire which is exposed to the flow of intake air. By applying a specific electrical current to the wire, the ECM heats it to a specific temperature. The flow of incoming air cools both the wire and an internal thermistor, affecting their resistance. To maintain a constant current value, the ECM varies the voltage applied to these components of the MAF meter. The voltage level is proportional to the airflow through the sensor, and the ECM uses it to calculate the intake air volume.
The ECM monitors the average engine load value ratio to check the MAF meter for malfunctions. The average engine load value ratio is obtained by comparing the average engine load calculated from the MAF meter output to the average engine load estimated from the driving conditions, such as the engine speed and the throttle opening angle. If the average engine load value ratio is below the threshold value, the ECM determines that the intake air volume is low, and if the average engine load value ratio is above the threshold value, the ECM determines that the intake air volume is high.
If this is detected in 2 consecutive driving cycles, the MIL is illuminated and a DTC is stored.

MONITOR STRATEGY


Related DTCs
P0101: Mass air flow meter rationality
Required Sensors/Components (Main)
Mass air flow meter
Required Sensors/Components (Related)
Crankshaft Position (CKP) sensor, Engine Coolant Temperature (ECT) sensor and Throttle Position (TP) sensor
Frequency of Operation
Continuous
Duration
10 times
MIL Operation
2 driving cycles
Sequence of Operation
None

TYPICAL ENABLING CONDITIONS


Monitor runs whenever following DTCs not present
None
Throttle position (TP sensor voltage)
0.24 V to 2 V
Time after engine start
5 seconds or more
Battery voltage
10.5 V or more
Engine coolant temperature
70°C (158°F) or more
Estimated load
30 to 70%
IAT sensor circuit (P0110, P0112, P0113)
OK
ECT sensor circuit (P0115, P0117, P0118)
OK
CKP sensor circuit (P0335)
OK
TP sensor circuit (P0120, P0121, P0122, P0123, P0220, P0222, P0223, P2135)
OK
Canister pressure sensor circuit (P0450, P0452, P0453)
OK
EVAP leak detection pump (P2401, P2402)
OK
EVAP vent valve (P2419, P2420)
OK

TYPICAL MALFUNCTION THRESHOLDS


Both of following conditions 1 and 2 met
-
1. Averaged engine load value ratio
Less than 0.85, or more than 1.15 (varies with estimated engine load)
2. Averaged air-fuel ratio
Less than -20%, or more than 20%

CONFIRMATION DRIVING PATTERN


Yaris. Ncp93, 131.1Nz-Fe Engine Control.Sfi System (For Sedan). Dtc P0101 Mass Air Flow Circuit Range / Performance Problem

  1. Connect the Techstream to the DLC3.
  2. Turn the ignition switch to ON.
  3. Turn the Techstream on.
  4. Clear DTCs (even if no DTCs are stored, perform the clear DTC operation).
  5. Turn the ignition switch off and wait for at least 30 seconds.
  6. Turn the ignition switch to ON and turn the Techstream on.
  7. Start the engine and warm it up until the engine coolant temperature reaches 70°C (158°F) or higher [A].
  8. Drive the vehicle at approximately 80 km/h (50 mph) to 112 km/h (70 mph) for 5 minutes or more [B].
    CAUTION:
    When performing the confirmation driving pattern, obey all speed limits and traffic laws.
    HINT:
    Drive while keeping the engine load as stable as possible.
  9. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [C].
  10. Read pending DTCs.
    HINT:
    1. If a pending DTC is output, the system is malfunctioning.
    2. If a pending DTC is not output, perform the following procedure.
  11. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
  12. Input the DTC: P0101.
  13. Check the DTC judgment result.

    Techstream Display
    		Description
    NORMAL
    1. DTC judgment completed
    2. System normal
    ABNORMAL
    1. DTC judgment completed
    2. System abnormal
    INCOMPLETE
    1. DTC judgment not completed
    2. Perform driving pattern after confirming DTC enabling conditions
    N/A
    1. Unable to perform DTC judgment
    2. Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit
    HINT:
    1. If the judgment result shows NORMAL, the system is normal.
    2. If the judgment result shows ABNORMAL, the system has a malfunction.
    3. If the judgment result shows INCOMPLETE or N/A, perform steps [B] through [C] again.
  14. If no pending DTC is output, perform a universal trip and check for permanent DTCs (YARIS_NCP93 RM000000PDK0QGX.html).
    HINT:
    1. If a permanent DTC is output, the system is malfunctioning.
    2. If no permanent DTC is output, the system is normal.

WIRING DIAGRAM

Refer to DTC P0100 (YARIS_NCP93 RM000000U5B0ITX_07.html).

INSPECTION PROCEDURE

NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
HINT:
Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air fuel ratio was lean or rich, and other data from the time the malfunction occurred.
1.CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0101)

  1. Connect the Techstream to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the Techstream on.

  1. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

  1. Read DTCs.

    Result
    Display (DTC Output)
    		Proceed To
    P0101
    		A
    P0101 and other DTCs
    		B
HINT:
If any DTCs other than P0101 are output, troubleshoot those DTCs first.


B
GO TO DTC CHART (YARIS_NCP93 RM000000PDF0E6X.html)
A


2.CHECK INTAKE SYSTEM

  1. Check the intake system for vacuum leakage (YARIS_NCP93 RM0000032ZM008X_01_0001.html).

    OK:
    No leakage from intake system.


NG
REPAIR OR REPLACE INTAKE SYSTEM
OK


3.CHECK PCV HOSE CONNECTIONS
OK:
PCV hose is connected correctly and is not damaged.


NG
REPAIR OR REPLACE PCV HOSE
OK

REPLACE MASS AIR FLOW METER (YARIS_NCP93 RM000001D0M01PX_01_0001.html)