P0172

DTC P0172 SYSTEM TOO RICH (BANK 1)

1. OUTLINE OF DIAGNOSIS
Detect the fuel system malfunction by the amount of main feedback control.

- Diagnostic Method
Fuel system is diagnosed by comparing the target air fuel ratio calculated by ECM with the actual air fuel ratio measured by sensor.




2. ENABLE CONDITION

3. GENERAL DRIVING CYCLE
Perform the diagnosis continuously at engine idling after warmup or a constant speed.

4. DIAGNOSTIC METHOD




- Abnormality Judgment
Judge that the fuel system malfunction occurs when the continuous time of completing the malfunction criteria below becomes more than 50 seconds by comparing the diagnosed value (fsobd) with threshold value.




- Normality Judgment
Judge OK when the continuous time of completing the malfunction criteria below becomes more than 10 seconds.

5. DTC CLEAR CONDITION
- When the OK idling cycle was completed 40 times in a row
- When "Clear Memory" was performed

6. MALFUNCTION INDICATOR LIGHT CLEAR CONDITION
- When OK with similar drive in 3 drive cycles.
- When "Clear Memory" was performed

7. FAIL SAFE
Purge control solenoid valve control: Not allowed to purge.

8. ECM OPERATION AT DTC SETTING
Memorize the freeze frame data. (For test mode $02)