1Nz-Fe Engine Control. Dtc P0100 Mass Or Volume Air Flow Circuit

The Mass Air Flow (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 the 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 given 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 in 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 circuit is constructed so that the platinum hot wire and the temperature sensor create a bridge circuit, and the power transistor is controlled so that the potentials of A and B remain equal to maintain the predetermined temperature.

HINT:

When any of these DTCs are stored, the ECM enters fail-safe mode. During fail-safe mode, the ignition timing is calculated by the ECM, according to the engine RPM and throttle valve position. Fail-safe mode continues until a pass condition is detected.

Yaris. Ncp93, 131.1Nz-Fe Engine Control.Sfi System (For Sedan).
Dtc
P0100 Mass Or Volume Air Flow Circuit

DTC No.	DTC Detection Condition	Trouble Area
P0100	MAF meter voltage less than 0.2 V, or more than 4.9 V, for 3 seconds (1 trip detection logic: Engine speed less than 4000 rpm) (2 trip detection logic: Engine speed more than 4000 rpm or more)	Open or short in MAF meter circuit MAF meter ECM
P0102	MAF meter voltage less than 0.2 V for 3 seconds (1 trip detection logic: Engine speed less than 4000 rpm) (2 trip detection logic: Engine speed 4000 rpm or more)	Open or short in MAF meter circuit MAF meter ECM
P0103	MAF meter voltage more than 4.9 V for 3 seconds (1 trip detection logic: Engine speed less than 4000 rpm) (2 trip detection logic: Engine speed 4000 rpm or more)	Open or short in MAF meter circuit MAF meter ECM

HINT:

When any of these DTCs are stored, check the air-flow rate by entering the following menus on a Techstream: Powertrain / Engine and ECT / Data List / MAF.

Mass Air Flow Rate (gm/sec)	Malfunction
Approximately 0.0	Open in Mass Air Flow (MAF) meter power source circuit Open or short in VG circuit
160.0 or more	Open in E2G circuit

MONITOR DESCRIPTION

If there is a defect in the MAF meter or an open or short circuit, the voltage level deviates from the normal operating range. The ECM interprets this deviation as a malfunction in the MAF meter and stores a DTC.
Example:
When the sensor output voltage remains less than 0.2 V, or more than 4.9 V, for more than 3 seconds, the ECM stores a DTC.
If the malfunction is not repaired successfully, a DTC is stored 3 seconds after the engine is next started.

MONITOR STRATEGY

Related DTCs	P0100: MAF meter range check (Fluctuating) P0102: MAF meter range check (Low voltage) P0103: MAF meter range check (High voltage)
Required Sensors/Components (Main)	MAF meter
Required Sensors/Components (Related)	Crankshaft position sensor
Frequency of Operation	Continuous
Duration	3 seconds
MIL Operation	Immediate: Engine RPM less than 4000 rpm 2 driving cycles: Engine RPM 4000 rpm or more
Sequence of Operation	None

TYPICAL ENABLING CONDITIONS

Monitor runs whenever following DTCs not present

None

TYPICAL MALFUNCTION THRESHOLDS

P0100:
MAF meter voltage	Less than 0.2 V, or more than 4.9 V

P0102:
MAF meter voltage	Less than 0.2 V

P0103:
MAF meter voltage	More than 4.9 V

COMPONENT OPERATING RANGE

MAF meter voltage

Between 0.4 V and 2.2 V

CONFIRMATION DRIVING PATTERN

Connect the Techstream to the DLC3.
Turn the ignition switch to ON and turn the Techstream on.
Clear DTCs (even if no DTCs are stored, perform the clear DTC operation).
Turn the ignition switch off and wait for at least 30 seconds.
Turn the ignition switch to ON and turn the Techstream on [A].
Start the engine.
Idle the engine for 5 seconds [B].
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [C].
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.
Run the engine at an engine speed of 4000 rpm or more for 5 seconds [D].
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [E].
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.
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Input the DTC: P0100, P0102 or P0103.

Check the DTC judgment result.

Techstream Display	Description
NORMAL	DTC judgment completed System normal
ABNORMAL	DTC judgment completed System abnormal
INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions
N/A	Unable to perform DTC judgment Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

HINT:

If the judgment result shows NORMAL, the system is normal.
If the judgment result shows ABNORMAL, the system has a malfunction.
If the judgment result shows INCOMPLETE or N/A, perform steps [B] through [E] again.

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

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.READ VALUE USING TECHSTREAM (MAF)

Connect the Techstream to the DLC3.

Start the engine.

Turn the Techstream on.

Enter the following menus: Powertrain / Engine and ECT / Data List / MAF.

Read the values displayed on the Techstream.
Result
MAF (gm/sec)
Proceed to
0.0
A
160.0 or more
B
Between 1.0 and 160.0*
C
*: The value must change when the throttle valve is opened or closed with the engine running

Result
MAF (gm/sec)	Proceed to
0.0	A
160.0 or more	B
Between 1.0 and 160.0*	C

Go to step 6

CHECK FOR INTERMITTENT PROBLEMS (YARIS_NCP93 RM000000PDQ0NOX.html)

A

2.CHECK TERMINAL VOLTAGE (POWER SOURCE OF MASS AIR FLOW METER)

Disconnect the mass air flow meter connector.

Turn the ignition switch to ON.

Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Tester Connection
Switch Condition
Specified Condition
C26-1 (+B) - Body ground
Ignition switch ON
11 to 14 V
Text in Illustration
*a
Front view of wire harness connector
(to Mass Air Flow Meter)

Text in Illustration
*a	Front view of wire harness connector (to Mass Air Flow Meter)

Reconnect the mass air flow meter connector.

Go to step 5

OK

3.CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)

Disconnect the mass air flow meter connector.

Disconnect the ECM connector.

Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):
Tester Connection
Condition
Specified Condition
C26-3 (VG) - C20-118 (VG)
Always
Below 1 Ω
C26-2 (E2G) - C20-116 (E2G)
Standard Resistance (Check for Short):
Tester Connection
Condition
Specified Condition
C26-3 (VG) or C20-118 (VG) - Body ground
Always
10 kΩ or higher

Reconnect the mass air flow meter connector.

Reconnect the ECM connector.

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

4.INSPECT MASS AIR FLOW METER

Perform On-vehicle Inspection (YARIS_NCP93 RM000001D0M01PX.html).

Perform Inspection (YARIS_NCP93 RM00000211409TX_03_0051.html).

Inspect the function of the mass air flow meter.
1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the Techstream on.
4. Enter the following menus: Powertrain / Engine and ECT / Data List / MAF.
5. Start the engine.
6. Check that the mass air flow meter value changes when the engine is raced.
  OK:
  The reading changes.

REPLACE MASS AIR FLOW METER (YARIS_NCP93 RM000001D0L00WX.html)

REPLACE ECM (YARIS_NCP93 RM000001CN002AX.html)

5.CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - EFI RELAY)

Disconnect the mass air flow meter connector.

Remove the integration relay from the engine room relay block.

Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):
Tester Connection
Condition
Specified Condition
C26-1 (+B) - 1A-4
Always
Below 1 Ω
Standard Resistance (Check for Short):
Tester Connection
Condition
Specified Condition
C26-1 (+B) or 1A-4 - Body ground
Always
10 kΩ or higher

Reinstall the integration relay.

Reconnect the mass air flow meter connector.

REPAIR OR REPLACE HARNESS OR CONNECTOR

CHECK ECM POWER SOURCE CIRCUIT (YARIS_NCP93 RM000001DN805UX.html)

6.CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)

Disconnect the mass air flow meter connector.

Disconnect the ECM connector.

Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):
Tester Connection
Condition
Specified Condition
C26-3 (VG) - C20-118 (VG)
Always
Below 1 Ω
C26-2 (E2G) - C20-116 (E2G)
Standard Resistance (Check for Short):
Tester Connection
Condition
Specified Condition
C26-3 (VG) or C20-118 (VG) - Body ground
Always
10 kΩ or higher

Reconnect the mass air flow meter connector.

Reconnect the ECM connector.

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

7.CHECK HARNESS AND CONNECTOR (SENSOR GROUND)

Disconnect the mass air flow meter connector.

Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):
Tester Connection
Condition
Specified Condition
C26-2 (E2G) - Body ground
Always
Below 1 Ω

Reconnect the mass air flow meter connector.

REPLACE ECM (YARIS_NCP93 RM000001CN002AX.html)

REPLACE MASS AIR FLOW METER (YARIS_NCP93 RM000001D0L00WX.html)

Tester Connection	Switch Condition	Specified Condition
C26-1 (+B) - Body ground	Ignition switch ON	11 to 14 V

Tester Connection	Condition	Specified Condition
C26-3 (VG) - C20-118 (VG)	Always	Below 1 Ω
C26-2 (E2G) - C20-116 (E2G)	Always	Below 1 Ω