P0068

DTC P0068 MAP/MAF - THROTTLE POSITION CORRELATION

1. OUTLINE OF DIAGNOSIS
Detect the malfunction of intake manifold pressure sensor output property. Judge 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 NG when either Low side or High side becomes NG. Judge NG when the continuous time of completing the malfunction criteria becomes more than predetermined time.




- Normality Judgment
Judge OK and clear the NG when both Low side and High side become OK. Judge OK when the malfunction criteria are completed.

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

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

8. FAIL SAFE
- Intake manifold pressure sensor process: Estimate the pressure from engine speed and throttle position. When also throttle position is NG, adopt 66.7 kPa (500 mmHg, 19.69 in Hg) as definite value.
- Heavy fuel judgment: Not allowed to carry out the heavy judgment.
- Fuel cut control: Fuel cut will operate at engine high speed.
- EVAP density learning (Fuel): Not allowed to learn
- Knocking compensation
At normal condition: Self-learning ignition advance value = knock F/B advance + overall self-learning advance value + partial self-learning advance value
When malfunctioning: Self-learning ignition advance value = -6 degree CA (6 degree CA retard) Knock F/B advance value = 0 degree CA
Prohibit overall self-learning
Partially prohibit self-learning
- ISC control: Not allowed to calculate the amount of ISC feedback.
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)