Unfortunately, this means of diagnosis really is limiting. The info that is necessary is the adaptation numbers and you must have a scanner for that.

The code 19 problem happens in any system. It means you have reached the limit of electronic adaptation. The LH problem arose over LH systems in hot humid climates that got richer with great regularity. At lower partial adapt numbers of about .85 the limit was reached.

OBDII cars have the same problems with lean running AMMs where they bump the limits at 1.32 or so. They trip P0170 and P0173 codes. But notice the numbers. The early cars only had 15% correction built into the software. The MB solution was new software encased in new hardware. As Jim and others have found, that software rides on a 36k chip that is easily readable and new ones programmed. Why MB makes everyone buy the hardware over is beyond me. Anumber of companies allowed updated software by just replacing the chips (BMW, Volvo and GM come to mind)

Part of the point is that with failures the system logically can't correct for ever. The new ones with 32% mixture correction on both sides of the original equation 1.000 are really amazing.

So when dealing with this issue the amount of correction is one consideration, but solving the deviation is another. If the mix has gone rich due to pressure changes then fixing that is the point.

If the thing runs "rich" at .85 and still has closed loop control then software can solve the problem. New software (MB list at over 1800 usually) will allow that .85 car to go to probably .68. The 119 LH cars that were fixed with software seemed to get long term correction at about .82 from what I have seen and heard. In these cases the software is a good solution.

I am pretty certain I have had code 19 on HFM cars that were at the .85 not .68 level.

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