DTC - General Description

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 CONDITION






Map 1






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 meeting the malfunction criteria below continues for 10 sec x 5 time or more, judge that there is a fault in the fuel system.






Map 2






Time Needed for Diagnosis: 10 sec x 5 time
Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.

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






Time Needed for Diagnosis: 10 sec

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.
- Heavy fuel judgment control: Not allowed to carry out the heavy judgment.

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