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Additive adaptation.

Additive adaptation.





If the closed loop system continuously corrects a deviation in the fuel system, it will be adapted. Adaptation takes place every five minutes and takes 30 seconds. Additive adaptation, which is 0.000 mg fuel/combustion when the control module is new or de-energized, is always added to the fuel quantity. Additive adaptation takes place at idling speed. Purging is stopped during adaptation because no other factor which can affect the fuel must be active.

Fuel is added or subtracted until the closed loop value fluctuates round 1.00 (0%). Additive adaptation is necessary because air leakage at idling speed leads to a major fault which must not be adapted multiplicatively as the quantity of fuel would then become much too large as soon as an increase in load occurred.

The limits for additive adaptation are minus 4 and 4 mg fuel/combustion respectively.

After the engine has started, multiplicative adaptation must always take place before additive adaptation.

The following conditions must be fulfilled before additive adaptation can take place:


• Closed loop must be active.

• No purging may occur; this takes place for 4 minutes and 30 seconds every 5-minute period.

• The coolant temperature must exceed 75 °C.

• Engine speed 750-950 rpm.

• Engine load 90-200 mg/c.

• The car must be stationary.


Diagnostics


• When the additive value reaches +4 mg fuel/combustion, diagnostic trouble code P1181 will be generated.

The most probable cause of the fault is:

- Air leakage after the throttle.

- Low fuel pressure.



• When the additive value reaches -4 mg fuel/combustion, diagnostic trouble code P1182 will be generated.

The most probable cause of the fault is:

- The purge valve has jammed in the open position.

- Air leakage before the throttle.