Getting a code 42 on my 91 4runner 3.0 manual 4wd. Bad speed sensor (VSS) seems to be the common cause of this. The issue is I'm not sure where this (these?) are on the 4wd. It seems 1 might be on the dash cluster, and the other somewhere else, but I'm having a hard time finding info on this. Anyone have experience with this on the 3.0 4wd and can tell me the locations of the speed sensors?

 

Does your speedometer work? If it does, you almost certainly have the mechanical speedometer and the reed switch in the combination meter is not getting the signal to the ECM. If the speedo doesn't work, you need to figure out if you have mechanical or electronic drive. Start by looking on the back of the transfer case. You will see either a drive cable to the speedometer, or you will see a sensor connected to a 3-conductor wire, which goes to the combination meter. (My '94 has the electronic speedo; I don't know when or why you might have the mechanical speedo). That sensor (VSS1) can fail (some have claimed success disassembling and cleaning, but ...)

 

I have a mechanical one but the speedometer does not work.. so maybe it's an issue with the cable. I have ordered a new combination meter to try that first, then I will test if the speedometer works again. If not I reckon I will need to replace the cable. The speed sensor on mine is apparently in the speedometer assembly on the combination meter.