P0103
1NZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0100: Mass or Volume Air Flow Circuit
DTC P0100 - Mass or Volume Air Flow Circuit
DTC P0102 - Mass or Volume Air Flow Circuit Low Input
DTC P0103 - Mass or Volume Air Flow Circuit High Input
DESCRIPTION
The Mass Air Flow (MAF) 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 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 these components in the MAF meter. 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 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.
HINT: When any of these DTCs are set, check the air-flow rate by selecting the following menu items on a Techstream: Powertrain / Engine and ECT / Data List / All Data / MAF.
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.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
P0100:
P0102:
P0103:
COMPONENT OPERATING RANGE
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT: Read freeze frame data using a Techstream. Freeze frame data record 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.
PROCEDURE
1. CHECK DTC OUTPUT
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch and turn the tester ON.
(c) Clear the DTCs.
(d) Allow the engine to idle for 1 minute or more.
(e) Select the following the menus items: Powertrain / Engine and ECT / DTC.
(f) Read the DTCs.
Result:
B -- CHECK FOR INTERMITTENT PROBLEMS
A -- Continue to next step.
2. READ VALUE USING TECHSTREAM (MASS AIR FLOW RATE)
(a) Read the values using the Techstream (MAF).
NOTICE:
- Turn the ignition switch off.
- Perform the inspection with the vehicle indoors and on a level surface.
- Perform the inspection of the mass air flow meter while it is installed in the air cleaner case (installed on the vehicle).
- During the test, do not use the exhaust air duct to perform suction on the exhaust pipe.
(b) Connect the Techstream to the DLC3.
(c) Turn the ignition switch to ON (do not start the engine).
(d) Turn the tester ON.
(e) Select the following the menus items: Powertrain / Engine and ECT / Data List / MAF.
(f) Wait for 30 seconds, and read the values on the Techstream.
Result:
B -- CHECK HARNESS AND CONNECTOR (SENSOR GROUND)
A -- Continue to next step.
3. INSPECT MASS AIR FLOW METER (POWER SOURCE VOLTAGE)
(a) Disconnect the C26 Mass Air Flow (MAF) meter connector.
(b) Turn the ignition switch to ON.
(c) Measure the voltage between the terminal of the wire harness side connector and body ground.
Standard voltage:
(d) Reconnect the MAF meter connector.
NG -- CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - INTEGRATION RELAY)
OK -- Continue to next step.
4. INSPECT MASS AIR FLOW METER (VG VOLTAGE)
(a) Remove the mass air flow meter with the wire harness connector connected.
(b) Connect a Techstream to the DLC3.
(c) Turn the ignition switch to ON.
(d) Turn the tester ON.
(e) Select the following the menus items: Powertrain / Engine and ECT / Data List / MAF.
(f) Check the MAF value when air is blown to the mass air flow meter, as shown in the illustration.
OK:
The MAF value changes.
NG -- REPLACE MASS AIR FLOW METER
OK -- Continue to next step.
5. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)
(a) Disconnect the C26 MAF meter connector.
(b) Disconnect the C20 ECM connector.
(c) Check the resistance.
Standard resistance (Check for open):
Standard resistance (Check for short):
(d) Reconnect the MAF meter connector.
(e) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE ECM
6. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - INTEGRATION RELAY)
(a) Disconnect the C26 MAF meter connector.
(b) Remove the integration relay from the engine room Relay Block (R/B).
(c) Check the resistance.
Standard resistance (Check for open):
Standard resistance (Check for short):
(d) Reconnect the MAF meter connector.
(e) Reinstall the integration relay.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- CHECK ECM POWER SOURCE CIRCUIT
7. CHECK HARNESS AND CONNECTOR (SENSOR GROUND)
(a) Disconnect the C26 MAF meter connector.
(b) Check the resistance.
Standard resistance:
(c) Reconnect the MAF meter connector.
OK -- REPLACE MASS AIR FLOW METER
NG -- Continue to next step.
8. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)
(a) Disconnect the C26 MAF meter connector.
(b) Disconnect the C20 ECM connector.
(c) Check the resistance.
Standard resistance (Check for open):
Standard resistance (Check for short):
(d) Reconnect the MAF meter connector.
(e) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE ECM