P0103
3MZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0102: Mass or Volume Air Flow Circuit Low Input
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 meter is a sensor that measures the amount of air flowing through the valve.
The ECM (included in the hybrid vehicle control ECU) uses this information to determine the fuel injection duration and to provide an 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 these components in the mass air flow 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 the Techstream: Powertrain / Engine and ECT / Data List / MAF.
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 (included in the hybrid vehicle control ECU) interprets this deviation as a malfunction in the mass air flow 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 the Techstream. The ECM (included in the hybrid vehicle control ECU) records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
PROCEDURE
1. READ VALUE USING TECHSTREAM
(a) Connect the Techstream to the DLC3.
(b) Put the engine in inspection mode Component Tests and General Diagnostics.
(c) Start the engine.
(d) Turn the Techstream on.
(e) Enter the following menus: Powertrain / Engine and ECT / Data List / MAF
(f) Read the values displayed on the Techstream.
Result:
*1: The value should be changed when the throttle valve is open or closed.
C -- CHECK FOR INTERMITTENT PROBLEMS
B -- INSPECT HYBRID VEHICLE CONTROL ECU
A -- Continue to next step.
2. INSPECT MASS AIR FLOW METER
(a) Disconnect the mass air flow meter connector.
(b) Turn the power switch on (IG).
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage:
(d) Reconnect the mass air flow meter connector.
NG -- INSPECT FUSE (EFI NO. 3 FUSE)
OK -- Continue to next step.
3. INSPECT HYBRID VEHICLE CONTROL ECU
(a) Put the engine in inspection mode Check Mode Procedure.
(b) Start the engine.
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage:
NG -- CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - HYBRID VEHICLE CONTROL ECU)
OK -- REPLACE HYBRID VEHICLE CONTROL ECU
4. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - HYBRID VEHICLE CONTROL ECU)
(a) Disconnect the mass air flow meter connector.
(b) Disconnect the hybrid vehicle 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 mass air flow meter connector.
(e) Reconnect the hybrid vehicle control ECU connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER - HYBRID VEHICLE CONTROL ECU)
OK -- REPLACE MASS AIR FLOW METER
5. INSPECT FUSE (EFI NO. 3 FUSE)
(a) Remove the EFI No. 3 fuse from the engine room relay block.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:
(c) Reconnect the mass air flow meter connector.
(d) Reinstall the EFI No. 3 fuse.
NG -- REPLACE FUSE (IGCT FUSE)
OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (MASS AIR FLOW METER - IGCT RELAY)
6. INSPECT HYBRID VEHICLE CONTROL ECU
(a) Measure the resistance according to the value(s) in the table below.
Standard resistance:
NG -- REPLACE HYBRID VEHICLE CONTROL ECU
OK -- Continue to next step.
7. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - HYBRID VEHICLE CONTROL ECU)
(a) Disconnect the mass air flow meter connector.
(b) Disconnect the hybrid vehicle 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 mass air flow meter connector.
(e) Reconnect the hybrid vehicle control ECU connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE MASS AIR FLOW METER