IN the USA only 1991 & later cars had ASR!!!
On that & any other 1991-93 car with ASR & CIS-E injection there isn't any rear diagnosis other than pin to pin testing!

Very HARD to diagnose! we hated to see those cars at the dealer! Even after pin to pin testing w/socket box the results always required a substitute part to be installed.

I do have wiring info & pin to pin testing info. Good luck

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MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
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44 years foreign automotive repair
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190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
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