Monitor Description
OUTLINE OF DIAGNOSIS
Detect the short circuit in the heated oxygen sensor heater.
The heated oxygen sensor heater performs duty control, and the output terminal voltage at ON is 0 V, and the output terminal voltage at OFF is the battery voltage.
Judge as NG when the terminal voltage remains High.
COMPONENT DESCRIPTION
| *A | Battery voltage | *B | Air fuel ratio sensor heater output voltage |
| *C | High error | - | - |
EXECUTION CONDITION
| Secondary parameters | Execution condition |
|---|---|
| Battery voltage | 10.9 V or higher |
| Heated oxygen sensor heater control duty | 25% or more |
GENERAL DRIVING CYCLE
After starting the engine, perform the diagnosis continuously when engine is low speed.
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 | 12 A or more |
Time needed for diagnosis
2.56 s
Malfunction indicator light illumination
Illuminates when malfunction occurs in 2 continuous driving cycles.