| DTC Code | DTC Name |
|---|---|
| P0102 | Mass Air Flow Circuit Low |
| P0103 | Mass Air Flow Circuit High |
| P010C | Mass or Volume Air Flow "A" Circuit Low Input |
| P010D | Mass or Volume Air Flow "A" 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 uses this information to determine the fuel injection time and to provide an 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 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 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.
Tech Tips
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.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P0102 P010C |
Mass air flow meter voltage is below 0.2 V for 3 seconds (1 trip detection logic) |
|
| P0103 P010D |
Mass air flow meter voltage is higher than 4.9 V for 3 seconds (1 trip detection logic) |
|
Tech Tips
When any of these DTCs are set, check the air-flow rate by entering the following menus: Powertrain / Engine / Data List / MAF Sensor 1 or MAF Sensor 2.
| Mass Air Flow Rate (gm/sec) | Malfunction |
|---|---|
| Approximately 0.0 |
|
| 160.0 or more |
|
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.
CONFIRMATION DRIVING PATTERN
Connect the GTS to the DLC3.
Turn the engine switch on (IG) and turn the GTS on.
Clear DTCs (even if no DTCs are stored, perform the clear DTC operation) Click here.
Turn the engine switch off and wait for at least 30 seconds.
Turn the engine switch on (IG) and turn the GTS on.
Wait 5 seconds or more.
Enter the following menus: Powertrain / Engine / Utility / All Readiness.
Input the DTC: P0102, P0103, P010C or P010D.
Check the DTC judgment result.
| Tester Display | Description |
|---|---|
| NORMAL |
|
| ABNORMAL |
|
| INCOMPLETE |
|
| N/A |
|
Tech Tips
If the judgment result shows NORMAL, the system is normal.
If the judgment result shows ABNORMAL, the system has a malfunction.
If the judgment result shows INCOMPLETE or N/A, perform the Confirmation Driving Pattern and the DTC judgment result again.
WIRING DIAGRAM
INSPECTION PROCEDURE
Tech Tips
Read freeze frame data using the GTS. Freeze frame data records the engine condition when malfunctions are detected. 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.
Bank 1 refers to the bank that includes the No. 1 cylinder*.
*: The No. 1 cylinder is the cylinder which is farthest from the transmission.
Bank 2 refers to the bank that does not include the No. 1 cylinder.
PROCEDURE
READ VALUE USING GTS (MASS AIR FLOW RATE)
Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Enter the following menus: Powertrain / Engine / Trouble Codes.
Read the DTC.
| Result | ||||||
|---|---|---|---|---|---|---|
|
| B |
|
INSPECT ECM (SENSOR GROUND) Click here |
| A |
|
INSPECT MASS AIR FLOW METER (POWER SOURCE VOLTAGE)
Disconnect the E13 or E22 MAF meter connector.
Turn the engine switch on (IG).
Measure the voltage according to the value(s) in the table below.
| Standard voltage | |||||||||
|---|---|---|---|---|---|---|---|---|---|
|
| NG |
|
CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - EFI FUSE) Click here |
| OK |
|
CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)
Disconnect the E13 or E22 MAF meter connector.
Disconnect the E1 ECM connector.
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 |
|
INSPECT MASS AIR FLOW METER
Inspect the mass air flow meter, referring to the On-vehicle Inspection for Mass Air Flow Meter Click here.
Inspect the mass air flow meter, referring to the Inspection for Mass Air Flow Meter Click here.
Inspect the function of the mass air flow meter.
Connect the GTS to the DLC3.
Turn the engine switch on (IG).
Turn the GTS on.
Enter the following menus: Powertrain / Engine / Data List / MAF Sensor 1 or MAF Sensor 2.
Start the engine.
Check that the MAF value changes when the engine is raced.
| OK |
|---|
| The reading changes. |
| NG |
|
REPLACE MASS AIR FLOW METER (BANK 1 OR BANK 2) Click here |
| OK |
|
REPLACE ECM Click here
INSPECT ECM (SENSOR GROUND)
Measure the resistance according to the value(s) in the table below.
| Standard resistance | |||||||||
|---|---|---|---|---|---|---|---|---|---|
|
| NG |
|
CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM) Click here |
| OK |
|
REPLACE MASS AIR FLOW METER (BANK 1 OR BANK 2) Click here
CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)
Disconnect the E13 or E22 MAF meter connector.
Disconnect the E1 ECM connector.
Measure the resistance according to the value(s) in the table below.
| Standard resistance | |||||||||
|---|---|---|---|---|---|---|---|---|---|
|
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
| OK |
|
REPLACE ECM Click here
CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - EFI FUSE)
Remove the EFI fuse from the engine room No. 2 relay block.
Disconnect the E13 or E22 MAF meter connector.
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 Click here