Toyota Tacoma manuals

Toyota Corolla Repair Manual: 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):
  1.  engine speed less than 900 rpm
  2.  throttle valve fully closed
  3.  mass air flow sensor output greater than 2.2 V
  4.  engine coolant temperature higher than 70 c (158 F)
  • Mass air flow sensor
Conditions (a) and (b) continue for more than 6 seconds: (2 trip detection logic)
  1.  vta greater than 0.1 V
  2.  mass air flow sensor output less than 0.4 V

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 airfuel 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 enabling conditions

Typical malfunction thresholds

Typical malfunction thresholds

Wiring diagram

Wiring diagram

Refer to dtc p0100

Mass or volume air flow circuit range/performance problem
Dtc p0101 mass or volume air flow circuit range/performance problem ...

Inspection procedure
Hint: read freeze frame data using the hand-held tester or the obd ii scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is usefu ...

Other materials:

Inspection procedure
Handheld tester: 1 Perform active test by handheld tester(operation of circuit opening relay) Connect the handheld tester to the dlc3.  turn the ignition switch on and push the handheld tester main switch on.  select the item diagnosis / enhanced obd ii / active test / fu ...

If a warning message or indicator is displayed (vehicles with a multi-information display)
If a warning is shown on the multi-information display, stay calm and perform the following actions: 1 Master warning light The master warning light also comes on or flashes in order to indicate that a message is currently being displayed on the multiinformation display. 2 Multi-information d ...

Replacement
1. Remove engine under cover rh 2. Drain coolant 3. Remove fan and generator v belt 4. Remove generator assy Disconnect the wire clamp from the wire clip on the rectifire end frame.  remove the rubber cap and nut, and disconnect the alternator wire.  disconnect the ...

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