| DTC Code | DTC Name |
|---|---|
| P010012 | Mass or Volume Air Flow Sensor "A" Circuit Short to Battery |
| P010017 | Mass or Volume Air Flow Sensor "A" Circuit Voltage Above Threshold |
DESCRIPTION
The mass air flow meter sub-assembly is a sensor that measures the amount of air flowing through the throttle valve. The ECM uses this information to determine fuel injection duration and to provide an appropriate air fuel ratio.
Inside the mass air flow meter sub-assembly, 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 specific 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.
Tech Tips
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, and the engine switch is then turned off.
| *1 | Temperature Sensor (Thermistor) |
| *2 | Power Transistor |
| *3 | Platinum Hot Wire (Heater) |
| *4 | Output Voltage |
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | MIL | Memory | Note |
|---|---|---|---|---|---|---|
| P010012 | Mass or Volume Air Flow Sensor "A" Circuit Short to Battery | The mass air flow meter sub-assembly voltage is higher than 4.9 V for 3 seconds. (1 trip detection logic: Engine speed is less than 4000 rpm) |
|
Comes on | DTC stored | SAE: P0103 |
| P010017 | Mass or Volume Air Flow Sensor "A" Circuit Voltage Above Threshold | The mass air flow meter sub-assembly voltage is higher than 4.9 V for 3 seconds. (2 trip detection logic: Engine speed is 4000 rpm or higher) |
|
Comes on | DTC stored | SAE: P0103 |
Tech Tips
When a DTC is output, check the Data List item "Mass Air Flow Sensor" using the GTS.
| DTC No. | Mass Air Flow Sensor | Malfunction |
|---|---|---|
| P010012 P010017 |
271.0 gm/sec or more |
|
If the Data List displays a normal value, the normal value may be due to a temporary recovery from the malfunction condition. Check for intermittent problems.
MONITOR DESCRIPTION
If there is a defect or an open or short circuit in the mass air flow meter sub-assembly, the voltage level deviates from the normal operating range. The ECM interprets this deviation as a malfunction in the mass air flow meter sub-assembly circuit and stores a DTC.
Example:
When the sensor output voltage remains higher than 4.9 V for 3 seconds, the ECM stores a DTC.
MONITOR STRATEGY
| Frequency of Operation | Continuous |
CONFIRMATION DRIVING PATTERN
Connect the GTS to the DLC3.
Turn the engine switch on (IG) and turn the GTS on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the engine switch off and wait for at least 30 seconds.
Turn the engine switch on (IG) and turn the GTS on [A].
Start the engine.
Idle the engine for 5 seconds [B].
Enter the following menus: Powertrain / Engine / Trouble Codes [C].
Read the pending DTCs.
Tech Tips
If a pending DTC is output, the system is malfunctioning.
If a pending DTC is not output, perform the following procedure.
Run the engine at an engine speed of 4000 rpm or higher for 5 seconds [D].
Enter the following menus: Powertrain / Engine / Trouble Codes [E].
Read the pending DTCs.
Tech Tips
If a pending DTC is output, the system is malfunctioning.
If a pending DTC is not output, perform the following procedure.
Enter the following menus: Powertrain / Engine / Utility / All Readiness.
Input the DTC: P010012 or P010017.
Check the DTC judgment result.
| GTS 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 steps [B] through [E] again.
WIRING DIAGRAM
CAUTION / NOTICE / HINT
Note
Inspect the fuses for circuits related to this system before performing the following procedure.
Tech Tips
Read freeze frame data using the GTS. 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
CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM)
Disconnect the mass air flow meter sub-assembly connector.
Disconnect the ECM connector.
Measure the resistance according to the value(s) in the table below.
| Standard Resistance | |||||||||
|---|---|---|---|---|---|---|---|---|---|
|
| Result | |||
|---|---|---|---|
|
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
| OK |
|
CHECK HARNESS AND CONNECTOR (SENSOR GROUND)
Disconnect the mass air flow meter sub-assembly connector.
Measure the resistance according to the value(s) in the table below.
| Standard Resistance | ||||||
|---|---|---|---|---|---|---|
|
Tech Tips
Perform "Inspection After Repair" after replacing the intake mass air flow meter sub-assembly.
| Result | |||
|---|---|---|---|
|
| OK |
|
REPLACE MASS AIR FLOW METER SUB-ASSEMBLY Click here |
| NG |
|
REPLACE ECM Click here |