P0103
2GR-FSE 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 throttle valve.
The ECM uses this information to determine the fuel injection time and to provide the 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 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 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 MAF 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 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 the Techstream. The ECM 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 Freeze Frame Data.
PROCEDURE
1. READ VALUE USING TECHSTREAM (MASS AIR FLOW RATE)
(a) Put the engine in inspection mode Inspection Mode Procedure.
(b) Connect the Techstream to the DLC3.
(c) Turn the Techstream on.
(d) Enter the following menus: Powertrain / Engine and ECT / Data List / MAF.
(e) Read the values displayed on the Techstream.
Result:
*1: The value must be changed when the throttle valve is open or closed with the engine running.
C -- CHECK FOR INTERMITTENT PROBLEMS
B -- CHECK HARNESS AND CONNECTOR (SENSOR GROUND)
A -- Continue to next step.
2. INSPECT MASS AIR FLOW METER (POWER SOURCE VOLTAGE)
(a) Disconnect the E42 Mass Air Flow (MAF) meter connector.
(b) Turn the power switch on (IG).
(c) Measure the voltage between the terminal of the wire harness side connector and body ground.
Standard voltage:
(d) Reconnect the MAF meter connector.
NG -- CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - EFI NO.2 FUSE)
OK -- Continue to next step.
3. INSPECT MASS AIR FLOW METER (VG VOLTAGE)
(a) Output voltage inspection.
(1) Apply battery voltage across terminals +B and E2G.
(2) Connect the positive (+) tester probe to terminal VG and negative (-) tester probe to terminal E2G.
(3) Measure the voltage.
Standard voltage:
NG -- REPLACE MASS AIR FLOW METER
OK -- Continue to next step.
4. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)
(a) Disconnect the E42 MAF meter connector.
(b) Disconnect the E83 ECM connector.
(c) Measure the resistance.
Standard resistance (Check for open):
Standard resistance (Check for short):
(d) Reconnect the MAF meter connector.
(e) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE ECM
5. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - EFI NO.2 FUSE)
(a) Disconnect the E42 MAF meter connector.
(b) Remove the EFI No.2 fuse from the engine room No. 1 relay block.
(c) Measure the resistance.
Standard resistance (Check for open):
Standard resistance (Check for short):
(d) Reconnect the MAF meter connector.
(e) Reinstall the EFI No.2 fuse.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- CHECK ECM POWER SOURCE CIRCUIT
6. CHECK HARNESS AND CONNECTOR (SENSOR GROUND)
(a) Disconnect the E42 MAF meter connector.
(b) Measure the resistance.
Standard resistance:
OK -- REPLACE MASS AIR FLOW METER
NG -- Continue to next step.
7. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)
(a) Disconnect the E42 MAF meter connector.
(b) Disconnect the E83 ECM connector.
(c) Measure the resistance.
Standard resistance (Check for open):
Standard resistance (Check for short):
(d) Reconnect the MAF meter connector.
(e) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE ECM