Monitor Description
OUTLINE OF DIAGNOSIS
Detect the stuck of heated oxygen sensor voltage in lean state.
When heated oxygen sensor voltage remains below the threshold value for predetermined time, diagnosis interrupts target air fuel ratio for control and raises output voltage.
Judge as NG detecting the stuck in lean state when heated oxygen sensor voltage remains below the threshold value even after the interrupt control.
COMPONENT DESCRIPTION
| *A | Electromotive force | *B | Air fuel ratio |
| *C | Lean | *D | Rich |
| *E | Theoretical air fuel ratio | *F | Comparative voltage |
EXECUTION CONDITION
| Secondary parameters | Execution condition |
|---|---|
| Battery voltage | 10.9 V or higher |
| Sub feedback | In operation |
| Amount of intake air | 10 g/s (0.35 oz/s) or more |
| Rear oxygen element impedance | 185Ω or less |
| Enable conditions at interrupt control are as follows | |
| Continuous time when heated oxygen sensor output voltage is less than 0.55 V | 5 s or more |
| Air fuel ratio reduced from target air fuel ratio | 11% |
GENERAL DRIVING CYCLE
Perform the diagnosis only once after the enable conditions have been established.
DIAGNOSTIC METHOD
If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.
Judgment value
| Malfunction Criteria | Threshold Value |
|---|---|
| Output voltage of heated oxygen sensor | Less than 0.55 V |
Time needed for diagnosis
15 ms
Malfunction indicator light illumination
Illuminates when malfunction occurs in 2 continuous driving cycles.