If I am not mistaken the old Rangers wern't capable of putting out scan data, all diagnostics are performed with a multimeter. You could ohm out the rear sensor, should probably be somewhere around 1500 ohms but usually if they are bad they will be open. You can pull the codes, it involves disconnecting a wire to the abs module and grounding it momentarily, if you want to let me know and I'll dig up the procedure for doing so....I'm to lazy to look right now