CIRCUIT OPERATION
- MFI relay is built into the IPDM E/R.
- Power is supplied to the heater power terminal of the linear air-fuel ratio sensor connector terminal number 3 from the MFI relay connector terminal.
- The heater of the linear air-fuel ratio sensor is controlled by the power transistor in the ECM connector terminal number 1.
TECHNICAL DESCRIPTION
The ECM checks whether the heater current is within a specified range when the heater is energized.
DESCRIPTIONS OF MONITOR METHODS
Linear air-fuel ratio sensor heater current is out of specified range.
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)
Sensor (The sensor below is determined to be normal)
Check Conditions
- While the linear air-fuel ratio sensor heater is on.
- 12V battery positive voltage is between 11.0 and 16.5 volts.
- More than 220 seconds have passed since the engine starting sequence was completed.
- Intake air temperature is higher than –10°C (14°F).
- On duty cycle of the linear air-fuel ratio sensor heater is between 25 and 75 percent.
Judgment Criterion
- The linear air-fuel ratio sensor heater current has continued to be lower than average 0.58 ampere for 10 seconds.
FAIL-SAFE AND BACKUP FUNCTION
None.
OBD-II DRIVE CYCLE PATTERN
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Linear air-fuel ratio sensor circuit harness damage or connector damage.
- Linear air-fuel ratio sensor heater failed.
- ECM failed.