By a built-in sensor unit, the manifold absolute pressure sensor detects the intake manifold pressure as a voltage. The ECM then determines the basic injection duration and basic injection advance angle based on this voltage. Since the manifold absolute pressure sensor does not use the atmospheric pressure as a criterion, but senses the absolute pressure inside the intake manifold (the pressure in proportion to the present absolute vacuum 0), it is not influenced by fluctuations in the atmospheric pressure due to high altitude and other factors. This permits it to control the air-fuel ratio at the proper lever under all conditions.

If the ECM detects DTC ”P0105” it operates the fail-safe function, keeping the ignition timing and injection volume constant and making it possible to drive the vehicle. HINT: After confirming DTC P0105 use the OBDII scan tool or TOYOTA hand-held tester to confirm the manifold absolute pressure from ”CURRENT DATA”.

INSPECTION PROCEDURE
HINT: If DTC ”P0105” (Manifold Absolute Pressure/Barometric Pressure Circuit Malfunction), ”P0110” (Intake Air Temp. Circuit Malfunction), ”P0115” (Engine Coolant Temp. Circuit Malfunction), ”P0120” (Throttle/Pedal Position Sensor/Switch ”A” Circuit Malfunction) are output simultaneously, E2 (sensor ground) may be open.

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