P0172

DTC P0172 SYSTEM TOO RICH (BANK 1)

1. OUTLINE OF DIAGNOSIS
Detect 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 CONDITIONS

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

4. DIAGNOSTIC METHOD




Abnormality Judgment
Compare the diagnosed value (fsobd) with the threshold value, and if a condition where the malfunction criteria are met continues for more than 50 seconds, judge that there is a fault in the fuel system.




Normality Judgment
Judge as OK when the malfunction criteria continues for 10 seconds.

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

6. MALFUNCTION INDICATOR LIGHT CLEAR CONDITIONS
- When similar driving conditions are repeated 3 times and the result is OK.
- When "Clear Memory" is 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)