Air Fuel Ratio Sensor And Heated Oxygen Sensor - Toyota 1NZ-FE User Manual

EG-32

Air Fuel Ratio Sensor and Heated Oxygen Sensor

1) General
D The air fuel ratio sensor and heated oxygen sensor differ in output characteristics.
D Approximately 0.4V is constantly applied to the air fuel ratio sensor, which outputs an amperage that
varies in accordance with the oxygen concentration in the exhaust emission. The ECM converts the
changes in the output amperage into voltage in order to linearly detect the present air-fuel ratio.
D The output voltage of the heated oxygen sensor changes in accordance with the oxygen concentration
in the exhaust emission. The ECM uses this output voltage to determine whether the present air-fuel
ratio is richer or leaner than the stoichiometric air-fuel ratio.
A1A+
(3.3V)
Air Fuel
Ratio
Sensor
A1A-
(2.9V)
Air Fuel Ratio Sensor Circuit
4.2
Air Fuel Ratio
Sensor Output (V)*
2.2
*: This calculation value is used internally in the ECM, and is not an ECM terminal voltage.
ENGINE - 1NZ-FE ENGINE
ECM
11 (Rich) 14.7
Air Fuel Ratio
OX1B
Heated
Oxygen
Sensor
EX1B
Heated Oxygen Sensor Circuit
: Air Fuel Ratio Sensor
: Heated Oxygen Sensor
1
Heated Oxygen
Sensor Output (V)
0.1
19 (Lean)
ECM
00REG21Y
D13N11