Boy, those are some real generic numbers.

The short term trim might mean something if I knew the units of measure it was expressed in. MB would call that value integrator or O2 something. It expresses where the control cycle is at the moment. It looks to be at the minus stop, but who knows? It really doesn't represent the adaptation values that are being faulted. it is an indication of momentary lean correction of a rich mixture.

The value faulted is either a partial load multiplicative adaptation or a CTP (closed throttle position)idle additive adaptation. The common senario on 112 and 113 motors is for the AMM to degrade such that at increasing air flow it is less accurate. (It misses more air as the volume increases). This is corrected by say a 15-25% multiplicative factor (25% more fuel). This is calculated at around 2000 rpms at a load that would probably accelerate the car. Once back at idle the AMM is more accurate and the system is now too rich due to the extra 15-25% fuel. This is delt with by a straight drop in mixture through an additive correction say -.8ms. This means that at idle with a normal injection open time of say 4.00ms a subtraction of .8ms takes place to wind up openning the injector 3.2ms.

The above example is of a car only part of the way out of range and is of the skewed type failure. Maybe more common is the straight line failure where its lean everywhere and at 32% correction it can't go no further. The limits are .68 to 1.32 on partial load multiplicative adaptation and -1.0ms to +1.0ms on the CTP additive adaption.

Anything that affects mixture affects these numbers, air leaks are high on the list.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician