P0102

FA20 ENGINE CONTROL: SFI SYSTEM: P0102, P0103; Mass or Volume Air Flow Circuit Low Input; 2013 MY FR-S [03/2012 -]
P0102 - Mass or Volume Air Flow Circuit Low Input
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 throttle valve. The ECM uses this information to determine the fuel injection time and to provide the 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 the wire and internal thermistor. 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 is stored, the ECM enters fail-safe mode. During fail-safe mode, the ignition timing is calculated by the ECM, according to the engine speed and throttle valve position. Fail-safe mode continues until a pass condition is detected.









HINT
When any of these DTCs are output, check the air-flow rate using the Techstream. Enter the following menus: Powertrain / Engine / 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 interprets this deviation as a malfunction in the mass air flow meter circuit and stores a DTC.

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS





TYPICAL MALFUNCTION THRESHOLDS

P0102





P0103





COMPONENT OPERATING RANGE





CONFIRMATION DRIVING PATTERN





1. Connect the Techstream to the DLC3.

2. Turn the ignition switch to ON and turn the Techstream on.

3. Clear DTCs (even if no DTCs are stored, perform the clear DTC operation) Reading and Clearing Diagnostic Trouble Codes.

4. Turn the ignition switch off and wait for at least 30 seconds.

5. Turn the ignition switch to ON and turn the Techstream on.

6. Start the engine and warm it up until the engine coolant temperature reaches 75°C (167°F) or higher.

7. With the vehicle stationary, depress the accelerator pedal and maintain an engine speed of between 2500 and 3000 rpm for 40 seconds or more [A].

8. Drive the vehicle at 10 km/h (6.25 mph) or more for 1 minute or more [B].

CAUTION:
When performing the confirmation driving pattern, obey all speed limits and traffic laws.

9. Enter the following menus: Powertrain / Engine / Trouble Codes.

10. Read pending DTCs.

HINT
* If a pending DTC is output, the system is malfunctioning.
* If a pending DTC is not output, perform the following procedure.

11. Enter the following menus: Powertrain / Engine / Utility / All Readiness.

12. Input the DTC: P0102 or P0103.

13. Check the DTC judgment result.





HINT
* If the judgment result shows NORMAL, the system is normal.
* If the judgment result shows ABNORMAL, the system has a malfunction.

14. If the test result is INCOMPLETE or N/A and no DTC is output, perform a universal trip and check for permanent DTCs Reading and Clearing Diagnostic Trouble Codes.

HINT
* If a permanent DTC is output, the system is malfunctioning.
* If no permanent DTC is output, the system is normal.

WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
Inspect the fuses for circuits related to this system before performing the following 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 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 DTC OUTPUT

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine / Trouble Codes.

(e) Read DTCs.

Result





B -- CHECK HARNESS AND CONNECTOR (SENSOR GROUND)
A -- Continue to next step.

2. CHECK TERMINAL VOLTAGE (POWER SOURCE OF MASS AIR FLOW METER)









(a) Disconnect the mass air flow meter connector.

(b) Turn the ignition switch to ON.

(c) Measure the voltage according to the value(s) in the table below.

Standard Voltage:





NG -- CHECK RELAY (EFI MAIN1)
OK -- Continue to next step.

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

(a) Disconnect the mass air flow meter connector.

(b) Disconnect the 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):





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

4. INSPECT MASS AIR FLOW METER

(a) Inspect the mass air flow meter, referring to the On-vehicle Inspection for Mass Air Flow Meter On-Vehicle Inspection.

(b) Inspect the mass air flow meter, referring to the Inspection for Mass Air Flow Meter Inspection.

(c) Inspect the function of the mass air flow meter.

(1) Connect the Techstream to the DLC3.

(2) Turn the ignition switch to ON.

(3) Turn the Techstream on.

(4) Enter the following menus: Powertrain / Engine / Data List / MAF.

(5) Start the engine.

(6) Check that the MAF value changes when the engine is raced.

OK:

The reading changes.

NG -- REPLACE MASS AIR FLOW METER Removal

OK -- REPLACE ECM Removal

5. CHECK HARNESS AND CONNECTOR (SENSOR GROUND)

(a) Disconnect the mass air flow meter connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for open):





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

OK -- REPLACE MASS AIR FLOW METER Removal

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

(a) Disconnect the mass air flow meter connector.

(b) Disconnect the 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):





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE ECM Removal

7. CHECK RELAY (EFI MAIN1)

(a) Inspect the EFI MAIN1 relay Testing and Inspection.

NG -- REPLACE RELAY (EFI MAIN1)
OK -- Continue to next step.

8. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - EFI MAIN1 RELAY)

(a) Disconnect the mass air flow meter connector.

(b) Remove the EFI MAIN1 relay from the engine room relay block assembly.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for open):





Standard Resistance (Check for short):





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- CHECK ECM POWER SOURCE CIRCUIT ECM Power Source Circuit