P0103
3MZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0100: Mass or Volume Air Flow Circuit
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 (Included in HV control ECU) 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.
HINT: When any of these DTCs are set, check the air-flow rate by entering the following menus on Techstream: Powertrain / Engine and ECT / Data List / All Data / MAF.
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 (Included in HV control ECU) 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.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
P0100:
P0102:
P0103:
COMPONENT OPERATING RANGE
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT: Read freeze frame data using Techstream. The ECM (Included in HV control ECU) 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.
PROCEDURE
1. READ VALUE USING TECHSTREAM (MASS AIR FLOW RATE)
(a) Connect Techstream to the DLC3.
(b) Put the engine in inspection mode Inspection Mode Procedure.
(c) Start the engine.
(d) Turn the tester ON.
(e) Enter the following menus: Powertrain / Engine and ECT / Data List / All Data / MAF.
(f) Read the values displayed on the tester.
Result:
*1: The value must be changed when the throttle valve is open or closed.
C -- CHECK FOR INTERMITTENT PROBLEMS
B -- INSPECT HV CONTROL ECU (SENSOR GROUND)
A -- Continue to next step.
2. INSPECT MASS AIR FLOW METER (POWER SOURCE VOLTAGE)
(a) Disconnect the M1 Mass Air Flow (MAF) meter connector.
(b) Turn the ignition switch to the ON position.
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage:
(d) Reconnect the MAF meter connector.
NG -- CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - IGCT NO. 4 FUSE)
OK -- Continue to next step.
3. INSPECT HV CONTROL ECU (VG VOLTAGE)
(a) Put the engine in inspection mode Inspection Mode Procedure.
(b) Start the engine.
(c) Measure the voltage between terminals VG and EVG of the H32 HV control ECU connector.
Standard voltage:
OK -- REPLACE HV CONTROL ECU
NG -- Continue to next step.
4. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - HV CONTROL ECU)
(a) Disconnect the M1 MAF meter connector.
(b) Disconnect the H32 HV control ECU connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open):
Standard resistance (Check for short):
(d) Reconnect the MAF meter connector.
(e) Reconnect the HV control ECU connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE MASS AIR FLOW METER
5. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - IGCT NO. 4 FUSE)
(a) Inspect the IGCT No. 4 fuse.
(1) Remove the IGCT No. 4 fuse from the R/B No. 3.
(2) Check the IGCT No. 4 fuse resistance.
Standard resistance:
Below 1 Ohms
(3) Reinstall the IGCT No. 4 fuse.
(b) Disconnect the M1 MAF meter connector.
(c) Remove the IGCT No. 4 fuse from the R/B No. 3.
(d) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open):
Standard resistance (Check for short):
(e) Reconnect the MAF meter connector.
(f) Reinstall the IGCT No. 4 fuse.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- CHECK ECM (INCLUDED IN HV CONTROL ECU) POWER SOURCE CIRCUIT
6. INSPECT HV CONTROL ECU (SENSOR GROUND)
(a) Measure the resistance according to the value(s) in the table below.
Standard resistance:
NG -- REPLACE HV CONTROL ECU
OK -- Continue to next step.
7. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - HV CONTROL ECU)
(a) Disconnect the M1 MAF meter connector.
(b) Disconnect the H32 HV control ECU connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open):
Standard resistance (Check for short):
(d) Reconnect the MAF meter connector.
(e) Reconnect the HV control ECU connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE MASS AIR FLOW METER