P0103
4GR-FSE 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 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 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 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.
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 entering the following menus on Techstream: Powertrain / Engine and ECT / Data List / All Data / MAF.
NOTICE:
- Perform the inspection with the vehicle indoors and on a lever surface.
- Perform the inspection of the MAF meter while it is installed to the air cleaner case (installed to the vehicle).
- During the test, do not use an exhaust air duct on the exhaust tail pipe assembly.
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 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 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 Freeze Frame Data.
PROCEDURE
1. READ VALUE USING MASS AIR FLOW METER (MAF)
(a) Connect Techstream to the DLC3.
(b) Turn the engine switch on (IG) (do not run the engine).
(c) Enter the following menus: Powertrain / Engine / Data List / All Data / MAF.
(d) Wait 30 seconds, and read the values on the tester.
NOTICE:
- Perform the inspection with the vehicle indoors and on a level surface.
- Perform the inspection of the MAF meter while it is installed to the air cleaner case (installed to the vehicle).
- During the test, do not use an exhaust air duct on the exhaust tail pipe assembly.
Result:
C -- CHECK FOR INTERMITTENT PROBLEMS
B -- INSPECT ECM (SENSOR GROUND)
A -- Continue to next step.
2. INSPECT MASS AIR FLOW METER (POWER SOURCE VOLTAGE)
(a) Disconnect the E29 Mass Air Flow (MAF) meter connector.
(b) Turn the engine switch on (IG).
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage:
(d) Reconnect the MAF meter connector.
NG -- CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - INTEGRATION RELAY)
OK -- Continue to next step.
3. INSPECT ECM (VG VOLTAGE)
(a) Start the engine.
(b) Measure the voltage according to the value(s) in the table below.
HINT:
The transmission gear selector lever should be in the neutral position and the A/C switch should be turned OFF.
Standard voltage:
OK -- REPLACE ECM
NG -- Continue to next step.
4. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)
(a) Disconnect the E29 MAF meter connector.
(b) Disconnect the E5 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):
(d) Reconnect the MAF meter connector.
(e) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE MASS AIR FLOW METER
5. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - INTEGRATION RELAY)
(a) Inspect the EFI No. 2 fuse.
(1) Remove the EFI No. 2 fuse from the engine room No. 2 relay block.
(2) Check the EFI No. 2 fuse resistance.
Standard resistance:
Below 1 Ohms
(3) Reinstall the EFI No. 2 fuse.
(b) Disconnect the E29 MAF meter connector.
(c) Remove the integration relay from the engine room J/B and R/B No. 2.
(d) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open):
Standard resistance (Check for short):
(e) Reconnect the MAF meter connector.
(f) Reinstall the integration relay.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- CHECK ECM POWER SOURCE CIRCUIT
6. INSPECT ECM (SENSOR GROUND)
(a) Measure the resistance according to the value(s) in the table below.
Standard resistance:
NG -- REPLACE ECM
OK -- Continue to next step.
7. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)
(a) Disconnect the E29 MAF meter connector.
(b) Disconnect the E5 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):
(d) Reconnect the MAF meter connector.
(e) Reconnect the ECM connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE MASS AIR FLOW METER