So I had to replace my rear diff and the old one had the hole for the abs sensor and now it was to late to get one just like my oem one and I had replaced it with one that doesn’t have it and now my sensor is zip-tied you guys thing that why I have the code 42 it says it for my speed sensor I am running 35s but not sure what I have to do. Thanks in advance

 

I'd bet money on it. If it's not set exactly where the computer thinks it should be it won't operate correctly.

 

Pretty sure the ABS and ECU codes are retrieved separately until atleast the late 90's. One flashes the CEL the other the ABS lamp.

Which are you seeing/using?

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Abs code 42 is over voltage.
ECU code 42 is VSS, you need to look and see if you have a cable drive speedo or electric sender on the side of the transmission. If it's cable drive you problem is somewhere in the dash between the speedometer and ECU.