Dtc P0100 Mass Or Volume Air Flow Circuit
Engine. Lexus Gs430, Gs300. Uzs190 Grs190
DESCRIPTION
MONITOR DESCRIPTION
WIRING DIAGRAM
INSPECTION PROCEDURE
READ VALUE USING INTELLIGENT TESTER (MASS AIR FLOW RATE)
INSPECT MASS AIR FLOW METER (POWER SOURCE VOLTAGE)
INSPECT ECM (VG VOLTAGE)
CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)
CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - INTEGRATION RELAY)
INSPECT ECM (SENSOR GROUND)
CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)
DTC P0100 Mass or Volume Air Flow Circuit |
DTC P0102 Mass or Volume Air Flow Circuit Low Input |
DTC P0103 Mass or Volume Air Flow Circuit High Input |
DESCRIPTION
The Mass Air Flow (MAF) meter is a sensor that measures the amount of air flowing through the valve.The ECM uses this information to determine the fuel injection time and to prove 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 provide 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 set, 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.
DTC No.
| DTC Detection Condition
| Trouble Area
|
P0100
| Open or short in Mass Air Flow (MAF) meter circuit for 3 seconds
| - Open or short in MAF meter circuit
- MAF meter
- ECM
|
P0102
| Open in Mass Air Flow (MAF) meter circuit for 3 seconds
| - Open in MAF meter circuit
- Short in MAF meter circuit
- MAF meter
- ECM
|
P0103
| Short in Mass Air Flow (MAF) meter circuit for 3 seconds
| - Short in MAF meter circuit (+B circuit)
- MAF meter
- ECM
|
- HINT:
- When any of these DTCs are set, check the air-flow rate by entering the following menus on the intelligent tester: Power train / Engine / Data List / MAF.
Mass Air Flow Rate (gm/s)
| Malfunctions
|
Approximately 0.0
| - Open in Mass Air Flow (MAF) meter power source circuit
- Open or short in VG circuit
|
271.0 or more
| - Open in EVG circuit
|
MONITOR DESCRIPTION
If there is a defect in the MAF meter or an open short circuit, the voltage level deviates from the normal operating range. The ECM interprets this deviation as a malfunction in the MAF meter and sets 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 sets a DTC.If the malfunction is not repaired successfully, a DTC is set 3 seconds after the engine is next started.
WIRING DIAGRAM
INSPECTION PROCEDURE
- HINT:
- Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions 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 (MASS AIR FLOW RATE) |
Connect the intelligent tester to the DLC3.
Start the engine.
Turn the tester ON.
Enter the following menus: Power train / Engine / Data List / MAF.
Read the values displayed on the tester.
- Result:
Mass Air Flow Rate (gm/s)
| Proceed to
|
0.0
| A
|
271.0 or more
| B
|
Between 1.0 and 270.0 (*1)
| C
|
*1: The value must be changed when the throttle valve is open or closed. | |
|
| | CHECK FOR INTERMITTENT PROBLEMS |
|
|
| 2.INSPECT MASS AIR FLOW METER (POWER SOURCE VOLTAGE) |
Disconnect the E42 Mass Air Flow (MAF) meter connector.
Turn the engine switch on (IG).
Measure the voltage between the terminals of the wire harness side connector and body ground.
- Standard voltage:
Tester Connection
| Specified Condition
|
+B (E42-1) - Body ground
| 9 to 14 V
|
Reconnect the MAF meter connector.
| 3.INSPECT ECM (VG VOLTAGE) |
Start the engine.
Measure the voltage between the terminals of the E6 ECM connector.
- HINT:
- The transmission gear selector lever should be in the P or N position and the A/C switch should be turned OFF.
- Standard voltage:
Tester Connection
| Condition
| Specified Condition
|
VG (E6-27) - E2G (E6-26)
| Engine idling
| 0.5 to 3.0 V
|
| 4.CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM) |
Disconnect the E42 MAF meter connector.
Disconnect the E6 ECM connector.
Measure the resistance.
- Standard resistance (Check for open):
Tester Connection
| Specified Condition
|
VG (E42-3) - VG (E6-27)
| Below 1 Ω
|
E2G (E42-2) - E2G (E6-26)
| Below 1 Ω
|
- Standard resistance (Check for short):
Tester Connection
| Specified Condition
|
VG(E42-3) or VG (E6-27) - Body ground
| 10 kΩ or higher
|
Reconnect the MAF meter connector.
Reconnect the ECM connector.
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
| OK |
|
|
|
| REPLACE MASS AIR FLOW METER |
|
| 5.CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - INTEGRATION RELAY) |
Inspect the EFI NO. 2 fuse.
Remove the EFI NO. 2 fuse from the engine room No. 2 relay block.
Measure the EFI NO. 2 fuse resistance.
- Standard resistance:
- Below 1 Ω
Reinstall the EFI NO. 2 fuse.
Disconnect the E42 MAF meter connector.
Remove the integration relay from the engine room No. 2 relay block.
Measure the resistance.
- Standard resistance (Check for open):
Tester Connection
| Specified Condition
|
+B (E42-1) - 2A-8
| Below 1 Ω
|
- Standard resistance (Check for short):
Tester Connection
| Specified Condition
|
+B (E42-1) or 2A-8 - Body ground
| 10 kΩ or higher
|
Reconnect the MAF meter connector.
Reinstall the integration relay.
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
| OK |
|
|
|
| CHECK ECM POWER SOURCE CIRCUIT |
|
| 6.INSPECT ECM (SENSOR GROUND) |
Measure the resistance.
- Standard resistance:
Tester Connection
| Specified Condition
|
E2G (E6-26) - Body ground
| Below 1 Ω
|
| 7.CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM) |
Disconnect the E42 MAF meter connector.
Disconnect the E6 ECM connector.
Measure the resistance.
- Standard resistance (Check for open):
Tester Connection
| Specified Condition
|
VG (E42-3) - VG (E6-27)
| Below 1 Ω
|
E2G (E42-2) - E2G (E6-26)
| Below 1 Ω
|
- Standard resistance (Check for short):
Tester Connection
| Specified Condition
|
VG (E42-3) or VG (E6-27) - Body ground
| 10 kΩ or higher
|
Reconnect the MAF meter connector.
Reconnect the ECM connector.
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
| OK |
|
|
|
| REPLACE MASS AIR FLOW METER |
|
