DTC P0102 Mass or Volume Air Flow Circuit Low Input
DTC P0103 Mass or Volume Air Flow Circuit High Input
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Inspect mass air flow meter sub-assembly (power source voltage)
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Check harness and connector (mass air flow meter sub-assembly - ecm)
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Check harness and connector (mass air flow meter sub-assembly - ecm)
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 the fuel injection time and to provide the 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 flow of incoming air cools both the wire and an internal thermistor, affecting their resistance. To maintain a constant temperature value of the hot wire, current is applied to these components in the mass air flow meter sub-assembly. 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 either 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 speed and throttle valve position. Fail-safe mode continues until a pass condition is detected.
| DTC No. | DTC Detection Condition | Trouble Area |
| P0102 | Mass air flow meter sub-assembly voltage is below 0.2 V for 3 seconds (1 trip detection logic). |
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| P0103 | Mass air flow meter sub-assembly voltage is higher than 4.9 V for 3 seconds (1 trip detection logic). |
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HINT:
When any of these DTCs are set, check the air-flow rate by entering the following menus: Powertrain / Engine and ECT / Data List / MAF.
| Mass Air Flow Rate (gm/sec) | Malfunction |
| Approximately 0.0 |
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| 271.0 or more | Open in E2G circuit |
Monitor description
If there is a defect in the mass air flow meter sub-assembly 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 sub-assembly circuit and sets a DTC.
Example:
When the sensor output voltage remains less than 0.2 V, or higher than 4.9 V, for more than 3 seconds, the ECM sets a DTC.
Monitor strategy
| Frequency of Operation | Continuous |
Confirmation driving pattern
- Put the engine in inspection mode (maintenance mode) .
- Start the engine and wait for 5 seconds or more.
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 intelligent tester. 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.
| 1.READ DTC OUTPUT (DTC P0102 AND P0103) |
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Connect the intelligent tester to the DLC3.
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Turn the power switch on (IG).
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Turn the tester on.
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Enter the following menus: Powertrain / Engine and ECT / DTC.
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Read the DTCs.
Result Result Proceed to DTC P0102 is output A DTC P0103 is output B
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| OK | |
| 2.INSPECT MASS AIR FLOW METER SUB-ASSEMBLY (POWER SOURCE VOLTAGE) |
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Disconnect the mass air flow meter sub-assembly connector.
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Turn the power switch on (IG).
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Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Tester Connection Switch Condition Specified Condition D5-3 (+B) - Body ground Power switch on (IG) 11 to 14 V Text in Illustration *a Front view of wire harness connector
(to Mass Air Flow Meter Sub-assembly)
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| OK | |
| 3.CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM) |
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Disconnect the mass air flow meter sub-assembly connector.
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Disconnect the ECM connector.
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Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection Condition Specified Condition D5-5 (VG) - D27-94 (VG) Always Below 1 ? D5-4 (E2G) - D27-117 (E2G) Always Below 1 ? D5-5 (VG) or D27-94 (VG) - Body ground Always 10 k? or higher
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| OK | |
| 4.INSPECT MASS AIR FLOW METER SUB-ASSEMBLY |
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Perform On-vehicle inspection .
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Perform Inspection .
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Inspect the function of the mass air flow meter sub-assembly.
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Connect the intelligent tester to the DLC3.
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Turn the power switch on (IG).
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Turn the tester on.
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Put the engine in inspection mode (maintenance mode) .
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Start the engine.
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Enter the following menus: Powertrain / Engine and ECT / Data List / MAF.
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Check that the reading of MAF changes when the engine is raced.
OK:
The reading changes.
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| OK | |
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| 5.CHECK HARNESS AND CONNECTOR (SENSOR GROUND) |
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Disconnect the mass air flow meter sub-assembly connector.
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Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection Condition Specified Condition D5-4 (E2G) - Body ground Always Below 1 ?
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| OK | |
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| 6.CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER SUB-ASSEMBLY - ECM) |
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Disconnect the mass air flow meter sub-assembly connector.
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Disconnect the ECM connector.
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Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection Condition Specified Condition D5-4 (E2G) - D27-117 (E2G) Always Below 1 ?
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| OK | |
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