DTC - General Description

DTC P0068 MAP/MAF - THROTTLE POSITION CORRELATION

1. OUTLINE OF DIAGNOSIS
Detect problems in the intake manifold pressure sensor output properties.
Judge as NG when the intake air pressure AD value is Low whereas it seemed to be High from the viewpoint of engine condition, or when it is High whereas it seemed to be Low from the engine condition.

2. COMPONENT DESCRIPTION






3. ENABLE CONDITION






4. GENERAL DRIVING CYCLE
Perform the diagnosis continuously after idling.

5. DIAGNOSTIC METHOD

- Abnormality Judgment
Judge as NG when Low side or High side becomes NG.
If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.






Time Needed for Diagnosis:
Low side: 3000 msec
High side: 10000 msec
Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.

- Normality Judgment
Judge as OK and clear the NG when both Low side and High side become OK.
If the duration of time while the following conditions are met is longer than the time indicated, judge as OK.






Time Needed for Diagnosis:
Low side: Less than 1 second
High side: Less than 1 second

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

7. MALFUNCTION INDICATOR LIGHT CLEAR CONDITIONS
- When the OK driving cycle is completed 3 times in a row
- When "Clear Memory" is performed

8. FAIL SAFE
- Intake manifold pressure sensor process: Estimate the pressure from the engine speed and size of the throttle opening. When the throttle opening is also NG, fix at 66.7 kPa (500 mmHg, 19.69 inHg).
- Heavy fuel judgment: Not allowed to carry out the heavy judgment.
- Fuel cut control: Fuel cut will operate at engine high speed.
- EVAP conc. learning (fuel): Not allowed to learn.
- Knocking compensation
When normal: Learning ignition advance angle value = knock F/B advance angle + entire learning advance angle value + portional learning advance angle value
Failure: learned ignition advance value = -6° CA. (6° CA retard)
Knock F/B advance angle value = 0° CA
Whole learning prohibited
Portional learning prohibited
- ISC control: ISC feedback amount calculation prohibited Amount of ISC open-loop compensation = Fixed at 6.82%
- Purge control: Not allowed to purge.

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