Toyota Corolla (E120) 2002–2008 Repair Manual / Diagnostics / Sfi system / Mass or volume air flow circuit
range/performance problem / Circuit description
Toyota Corolla (E120): Circuit description
Refer to dtcs p0100
Dtc no. |
Dtc detection condition | Trouble area |
P0101 | After engine is warmed up, conditions (a) to (d) continue for
more than 10 seconds (2 trip detection logic):
|
|
Conditions (a) and (b) continue for more than 6 seconds: (2 trip
detection logic)
|
Monitor description
The maf (mass air flow) sensor helps the ecm calculates the amount of air flowing through the throttle valve. The ecm uses this information to determine the fuel injection time and provides a proper air–fuel ratio.
Inside the maf sensor, there is a heated platinum wire exposed to the flow of intake air. By applying a specific current to the wire, the ecm heats this wire to a given temperature. The flow of incoming air cools the wire and an internal thermister, changing their resistance. To maintain a constant current value, the ecm varies the voltage applied to these components in the maf sensor. The voltage level is proportional to the air flow through the sensor and the ecm interprets this voltage as the intake air amount. If there is a defect in the sensor or an open or short circuit, the voltage level will deviate outside the normal operating range. The ecm interprets this deviation as a defect in the maf sensor and sets a dtc.
Example: if the voltage is more than 2.2 V at idle, or less than 0.4 V at idle off, the ecm interprets this as a defect in the maf sensor and sets a dtc.
Monitor strategy
Typical enabling conditions
Typical malfunction thresholds
Wiring diagram
Refer to dtc p0100
Other materials:
Driving support system
information display
■ Driving support system
information
Select to display the operational
status of the following systems:
LTA (Lane Tracing Assist)
LDA (Lane Departure Alertl)
Dynamic radar cruise control
■ Navigation system-linked
display (if equipped)
Select to display the following
navigation system-linke ...
Audio unit
1 Bluetooth® connection status
If “BT” is not displayed, the Bluetooth® audio/phone cannot be used.
2 Display
A message, name, number, etc. is displayed.
Lower-case characters and special characters cannot be displayed.
3 Displays the set up menu
4 Selects items such as menu and number
...
Circuit description
In the diagram below, when the engine is cranked, current flows from terminal
st2 of the ignition switch to
the starter relay coil and also current flows to terminal sta of the ecm (sta
signal).
When the sta signal and ne signal are input to the ecm, tr is turned on, current
flows to the c ...