CIRCUIT OPERATION
The linear air-fuel ratio sensor and the ECM are connected by the following three lines to detect the air-fuel ratio.
- The line between the linear air-fuel ratio sensor terminal number 6 and the ECM connector terminal number 54 detects the air-fuel ratio.
- The auxiliary line between the linear air-fuel ratio sensor connector terminal number 1 and the ECM connector terminal number 53 detects the air-fuel ratio.
- The line between the linear air-fuel ratio sensor connector terminal number 5 and the ECM connector terminal number 51 is connected to ground.
TECHNICAL DESCRIPTION
- The ECM effects air-fuel ratio feedback control in accordance with the signals from the linear air-fuel ratio sensor.
- If the linear air-fuel ratio sensor has deteriorated, corrections will be made by the heated oxygen sensor (rear).
DESCRIPTIONS OF MONITOR METHODS
If one of the three line voltages is excessively high or if all the three line voltages are excessively high, the DTC is set as a malfunction.
MONITOR EXECUTION
Continuous.
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC set in memory for the item monitored below)
- Linear air-fuel ratio sensor heater monitor
- Misfire monitor
- Fuel system monitor
Sensor (The sensor below is determined to be normal)
- Mass airflow sensor
- Engine coolant temperature sensor
- Intake air temperature sensor
- Barometric pressure sensor
- Throttle position sensor
- Fuel tank pressure sensor
DTC SET CONDITIONS
Check Condition
- 12V battery positive voltage is more than 10.0 volts and is less than 16.5 volts.
Judgment Criterions
- Ip+ input voltage has become 6.2 volts or more for 3 times.
or
- Vs+ input voltage has become 6.2 volts or more for 3 times.
or
- COM+ input voltage has become 4.0 volts or more for 3 times.
FAIL-SAFE AND BACKUP FUNCTION
Does not control air-fuel ratio closed loop.
OBD-II DRIVE CYCLE PATTERN
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Linear air-fuel ratio sensor failed.
- Shorted linear air-fuel ratio sensor circuit or connector damage.
- ECM failed.