Heated Oxygen Sensor (Rear)

FAULT ID
59

TITLE
Heated Oxygen Sensor (rear)

BACKGROUND
- The oxygen sensor converts the oxygen density in the exhaust gas to a voltage and outputs it.
- The engine control module checks an output voltage of the oxygen sensor when the oxygen volume in the exhaust gas is little (Air/fuel ratio is rich.).

RANGE OF CHECK
- Approx. 3 minutes or more have passed after engine was started.
- Engine coolant temperature is approx. 80°C (176°F) or more.
- Closed throttle position switch: OFF
- The throttle position sensor output voltage is 4.1 V or more.
- Open loop control in operation.
- 20 seconds have passed after deceleration finished.

SET CONDITIONS
- The heated oxygen sensor (rear) output voltage is 0.1 V or less.
- The heated oxygen sensor (front) output voltage is 0.5 V or more.
- The above conditions continue for a continuous period of 5 seconds.

EFFECT
Limp-in
- The air/fuel ratio feedback control (closed loop control) is performed only by using a signal of the oxygen sensor (front) which is installed on the front side of the catalytic converter.

PROBABLE CAUSES
- Oxygen sensor deteriorated.
- Open or shorted oxygen sensor circuit, or loose connector.
- Engine control module failed.