P0103

1NZ-FXE 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 MAF (Mass Air Flow) meter measures the amount of air flowing through the throttle valve. The ECM uses this information to determine the fuel injection time and provides a proper air-fuel ratio. Inside the MAF meter, there is a heated platinum wire exposed to the flow of intake air.
By applying a specific current to the wire, the ECM heats this wire to a given temperature. The flow of incoming air cools 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 air flowing through the sensor. The ECM interprets this voltage as the intake air amount.
The circuit is constructed so that the platinum hot wire and temperature sensor provide a bridge circuit, and the power transistor is controlled so that the potential of A and B remains equal to maintain the set temperature.









HINT: After confirming DTC P0100, P0102 or P0103, confirm the mass air flow ratio in Powertrain / Engine and ECT / Data List / All Data / MAF.





MONITOR DESCRIPTION

If there is a defect in the sensor or an open or short circuit, the voltage level will deviate from the normal operating range. The ECM interprets this deviation as a defect in the MAF meter and sets a DTC.
Example:
When the sensor voltage output is less than 0.2 V or more than 4.9 V and if either condition continues for more than 3 seconds.

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS

P0102:





P0103:





COMPONENT OPERATING RANGE





WIRING DIAGRAM





INSPECTION PROCEDURE
HINT: Read freeze frame data using 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) Connect Techstream to the DLC3.
(b) Turn the power switch on (ACC).
(c) Turn the power switch on (do not start the engine).
(d) Turn the Techstream ON.
(e) Enter the following menus: Powertrain / Engine and ECT / Data List / MAF.
(f) Wait 30 seconds, and read the values on the Techstream.
Result:
Less than 0.07 g/sec.
C -- CHECK FOR INTERMITTENT PROBLEMS
B -- CHECK ECM (SENSOR GROUND)
A -- Continue to next step.

2. INSPECT MASS AIR FLOW METER (POWER SOURCE)
(a) Turn the power switch ON (IG).




(b) Disconnect the M1 mass air flow meter connector.
(c) Measure the voltage between the terminal of the wire harness side connector and body ground.
Standard voltage:





(d) Reconnect the mass air flow meter connector.
NG -- CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - EFI M RELAY)
OK -- Continue to next step.

3. CHECK ECM (VG VOLTAGE)




(a) Put the engine in inspection mode Service Precautions.
(b) Start the engine.
(c) Measure the voltage between the specified terminals of the E5 ECM connector.
HINT: The A/C switch should be turned OFF.

Standard voltage:






OK -- REPLACE ECM
NG -- Continue to next step.

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




(a) Disconnect the M1 mass air flow meter connector.




(b) Disconnect the E5 ECM 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 ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE MASS AIR FLOW METER
5. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - EFI M RELAY)




(a) Remove the integration relay from the engine room relay block.




(b) Disconnect the M1 mass air flow meter 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) Reinstall the integration relay.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- CHECK ECM POWER SOURCE CIRCUIT
6. CHECK ECM (SENSOR GROUND)




(a) Measure the resistance between the specified terminal of the E5 ECM connector and body ground.
Standard resistance:






NG -- REPLACE ECM
OK -- Continue to next step.

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




(a) Disconnect the M1 mass air flow meter connector.




(b) Disconnect the E5 ECM 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 ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE MASS AIR FLOW METER