DTC P0100 P0102 P0103 2AD-FHV

DTC    P0100    Mass or Volume Air Flow Circuit

DTC    P0102    Air Flow Meter Circuit Low Input

DTC    P0103    Air Flow Meter Circuit High Input

Description

The mass air flow meter uses a platinum hot wire. The mass air flow meter consists of a platinum hot wire, a temperature sensor and a control circuit installed in a plastic housing. The mass air flow meter hot wire and temperature sensor (located in the intake air by-pass of the housing) detect changes in the intake air temperature.
The hot wire is maintained at the predetermined temperature by controlling the current flow through the hot wire. This current flow is then related as the output voltage of the mass air flow meter.
The circuit is constructed so that the platinum hot wire and temperature sensor provide a bridge circuit, with the power transistor controlled so that the potential of A and B remains equal to maintain the predetermined temperature.

 

Toyota fault code list DTC P0100 DTC P0102 DTC P0103

DTC No.	DTC Detection Condition	Trouble Area
P0100	Open or short in mass air flow meter circuit for more than 3 seconds with engine speed at 4,000 rpm or less (1 trip detection logic)	Open or short in mass air flow meter circuit Mass air flow meter ECM
P0102	Open in mass air flow meter circuit for more than 3 seconds with engine speed at 4,000 rpm or less (1 trip detection logic)
P0103	Short in mass air flow meter circuit for more than 3 seconds with engine speed at 4,000 rpm or less (1 trip detection logic)

HINT:

After confirming DTC P0100, P0102, or P0103, check the mass air flow ratio in the "Powertrain / Engine and ECT / Data List / MAF" menu using the intelligent tester.

Reference: 

Air Flow Value (g/sec.)	Malfunction
Approximately 0.0	Open in mass air flow meter power source circuit Open or short in VG circuit
174.0 or more	Open in EVG circuit

Wiring diagram

Inspection procedure

NOTICE:

After replacing the ECM, the new ECM needs registration and initialization.

HINT:

If DTCs relating to different systems are output, and they share terminal E2 as their ground, check this ground circuit first.

1.READ VALUE USING INTELLIGENT TESTER (MASS AIR FLOW RATE)

1. Connect the intelligent tester to the DLC3.

2. Start the engine and turn the tester ON.

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

4. Read the value.

   Result:

   Air flow rate (g/sec.)	Proceed to
   0.0	A
   174.0 or more	B
   Between 1 and 173.0*	C

   HINT:

* The value should change when the throttle valve is opened or closed.

B	Go to step 6
C	CHECK FOR INTERMITTENT PROBLEMS

A

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

1. Disconnect the B34 mass air flow meter connector.

2. Turn the ignition switch on (IG).

3. Measure the voltage of the terminal of the wire harness side connector and the body ground.

   Standard voltage:

   Tester Connection	Specified Condition
   B34-1 (+B) - Body ground	9 to 14 V

4. Reconnect the mass air flow meter connector.

NG	Go to step 5

OK

3.INSPECT MASS AIR FLOW METER (VG VOLTAGE)

1. Disconnect the B34 mass air flow meter connector.

2. Apply battery voltage across terminals +B and E2G.

3. Connect the positive (+) tester probe to terminal VG, and negative (-) tester probe to terminal E2G.

4. Measure the voltage of the wire harness side connector.

   Standard voltage:

   Tester Connection	Specified Condition
   B34-3 (VG) - B34-2 (E2G)	0.2 to 4.9 V

5. Reconnect the mass air flow meter connector.

OK	REPLACE ECM

NG

4.CHECK WIRE HARNESS (MASS AIR FLOW METER - ECM)

1. Disconnect the B34 mass air flow meter connector.

2. Disconnect the B32 ECM connector.

3. Measure the resistance of the wire harness side connectors.

   Standard resistance:

   Tester Connection	Specified Condition
   B34-3 (VG) - B32-65 (VG)	Below 1 Ω
   B34-2 (E2G) - B32-64 (EVG)	Below 1 Ω
   B34-3 (VG) or B32-65 (VG) - Body ground	10 kΩ or higher

4. Reconnect the mass air flow meter connector.

5. Reconnect the ECM connector.

NG	REPAIR OR REPLACE HARNESS AND CONNECTOR

OK
REPLACE ECM

5.CHECK WIRE HARNESS (MASS AIR FLOW METER - INTEGRATION RELAY)

1. Inspect the EFI NO. 1 fuse.

   1. Remove the EFI NO. 1 fuse from the engine room No. 1 relay block.

   2. Measure the resistance of the fuse.

      Standard resistance:

      Below 1 Ω

   3. Reinstall the EFI NO. 1 fuse.

2. Check the wire harness between the mass air flow meter and integration relay.

   1. Disconnect the B34 mass air flow meter connector.

   2. Remove the integration relay from the engine room No. 1 relay block.

   3. Measure the resistance of the wire harness side connectors.

      Standard resistance:

      Tester Connection	Specified Condition
      B34-1 (+B) - 1A-4	Below 1 Ω
      B34-1 (+B) or 1A-4 - Body ground	10 kΩ or higher

   4. Reconnect the mass air flow meter connector.

   5. Reinstall the integration relay.

NG	REPAIR OR REPLACE HARNESS AND CONNECTOR

OK
CHECK ECM POWER SOURCE CIRCUIT

6.CHECK WIRE HARNESS (SENSOR GROUND)

1. Disconnect the B34 mass air flow meter connector.

2. Measure the resistance of the wire harness side connector.

   Standard resistance:

   Tester Connection	Specified Condition
   B34-2 (E2G) - Body ground	Below 1 Ω

3. Reconnect the mass air flow meter connector.

NG	REPLACE ECM

OK

7.CHECK WIRE HARNESS (MASS AIR FLOW METER - ECM)

1. Disconnect the B34 mass air flow meter connector.

2. Disconnect the B32 ECM connector.

3. Measure the resistance of the wire harness side connectors.

   Standard resistance:

   Tester Connection	Specified Condition
   B34-3 (VG) - B32-65 (VG)	Below 1 Ω
   B34-2 (E2G) - B32-64 (EVG)	Below 1 Ω
   B34-3 (VG) or B32-65 (VG) - Body ground	10 kΩ or higher

4. Reconnect the mass air flow meter connector.

5. Reinstall the ECM connector.

NG	REPAIR OR REPLACE HARNESS AND CONNECTOR

OK
REPLACE ECM