I've got 2 1994 E420s. One of them gets the occasional error code 26. I usually ignore it and just clear the code. The car in question has never shifted gears exactly like the other. Not smooth and linear as it should be. More like kinda sharp, revvey, jolty all at low rpms. When you gun it all works as it should.

anywho, I thinking that all the weird tranny activity could be due to a need to change the tranny oil and filter. But I guess I would have the shop test the LH-SFI module.

BUT to the thread topic, would it be okay to take the module out of the good 420 and put it in the "bad" 420 without problems? If there is a difference would I be able to notice it immediate, or is the module such that it has to learn and therefore I wouldn’t notice a difference until some time and mileage has passed.

Since the transmissions are mechanical & NOT electronic (control wise) the computer should have NO effect on how they shift.

CODE 26 means that the catalyst warm-up on that isn't working properly!

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MERCEDES Benz Master Guild Technician (6 TIMES)
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To amplify MB Doc's point at a bit more, maybe the cat is plugged?? That would give you the symptoms you describe.

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'94 S500 Cpe

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oh, i thought that the code 26 was an upshift delay problem which could be related to vacuume lines that run to the tranny.

up-shift delay is HOW the catalytic converters are warmed-up more quickly!

They are warmed-up faster to allow the EMISSIONS to be reduced. NOT a trans function but an engine function.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Thanks for the replies guys. Got back from the shop, problem mostly likely is the valve body (bad news I know ).

BTW when the car is cold the car DOES delay to warm up the cats, so don’t think that it doesn’t. And the car passes emissions with flying colors. What’s with all the !'s ?