2Tr-Fe Engine Control. Dtc P0100 Mass Air Flow Circuit Malfunction

The mass air flow 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 mass air flow 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 the wire and internal thermistor. 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 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 either of these DTCs is stored, the ECM enters fail-safe mode. During fail-safe mode, the ignition timing is calculated by the ECM according to the engine speed and throttle valve position. The ECM continues operating in fail-safe mode until a pass condition is detected.

Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25.2Tr-Fe Engine Control.Sfi System (W/ Secondary Air Injection System).
Dtc
P0100 Mass Air Flow Circuit Malfunction

DTC No.	DTC Detection Condition	Trouble Area
P0100	Mass air flow meter circuit is open or shorted for more than 3 seconds (1 trip detection logic).	Open or short in mass air flow meter circuit Mass air flow meter ECM
P0102	Mass air flow meter voltage is below 0.2 V for 3 seconds (1 trip detection logic).	Open or short in mass air flow meter circuit Mass air flow meter ECM
P0103	Mass air flow meter voltage is higher than 4.9 V for 3 seconds (1 trip detection logic).	Open or short in mass air flow meter circuit Mass air flow meter ECM

HINT:

When either of these DTCs is stored, check the air flow rate by entering the following menus: Powertrain / Engine and ECT / Data List / All Data / MAF.

MAF (gm/s)	Malfunction
Approximately 0.0	Open in mass air flow 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 mass air flow 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 mass air flow meter and stores a DTC.
Example:
When the sensor output voltage remains below 0.2 V, or higher 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

Frequency of Operation

Continuous

CONFIRMATION DRIVING PATTERN

Turn the ignition switch to ON and wait for 5 seconds or more.

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 intelligent tester. Freeze frame data records the engine condition when malfunctions are detected. 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 INTELLIGENT TESTER (MAF)

Connect the intelligent tester to the DLC3.

Start the engine.

Turn the intelligent tester on.

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

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

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

Go to step 6

CHECK FOR INTERMITTENT PROBLEMS (HILUX_TGN26 RM000000PDQ0R4X.html)

A

2.INSPECT MASS AIR FLOW METER (POWER SOURCE VOLTAGE)

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
C36-1 (+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)

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:

Tester Connection
Condition
Specified Condition
C36-3 (VG) - C76-28 (VG)
Always
Below 1 Ω
C36-2 (E2G) - C76-30 (E2G)
Always
Below 1 Ω
C36-3 (VG) or C76-28 (VG) - Body ground
Always
10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

4.INSPECT MASS AIR FLOW METER

Inspect the mass air flow meter (HILUX_TGN26 RM000000Q2D08BX.html).

REPLACE MASS AIR FLOW METER (HILUX_TGN26 RM000000VW602CX.html)

REPLACE ECM (HILUX_TGN26 RM000000VW2023X.html)

5.CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - NO. 1 INTEGRATION RELAY)

Disconnect the mass air flow meter connector.

Remove the No. 1 integration relay from the engine room relay block and junction block.

Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection
Condition
Specified Condition
C36-1 (+B) - 1J-5
Always
Below 1 Ω
C36-1 (+B) or 1J-5 - Body ground
Always
10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

CHECK ECM POWER SOURCE CIRCUIT (HILUX_TGN26 RM000001DN806UX.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:

Tester Connection
Condition
Specified Condition
C36-3 (VG) - C76-28 (VG)
Always
Below 1 Ω
C36-2 (E2G) - C76-30 (E2G)
Always
Below 1 Ω
C36-3 (VG) or C76-28 (VG) - Body ground
Always
10 kΩ or higher

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:

Tester Connection
Condition
Specified Condition
C36-2 (E2G) - Body ground
Always
Below 1 Ω

REPLACE ECM (HILUX_TGN26 RM000000VW2023X.html)

REPLACE MASS AIR FLOW METER (HILUX_TGN26 RM000000VW602CX.html)

Tester Connection	Switch Condition	Specified Condition
C36-1 (+B) - Body ground	Ignition switch ON	11 to 14 V

Tester Connection	Condition	Specified Condition
C36-3 (VG) - C76-28 (VG)	Always	Below 1 Ω
C36-2 (E2G) - C76-30 (E2G)	Always	Below 1 Ω
C36-3 (VG) or C76-28 (VG) - Body ground	Always	10 kΩ or higher