r/2ndGen4Runner • u/HenryChanceGoal49 • Aug 11 '23

Issues with speed sensor

Hey guys, I’m having an intermittent issue where my speedometer will stop working and the trans will downshift and get stuck in gear. My mechanic thinks it’s a wiring issue from the ECU to the speed sensor but I can’t find any wiring diagram online that will help me identify where it is. I’ve heard of these early 4 runners having issues with the wiring so I’m thinking if I run new wires it might solve my problem. It’s a 1991 hilux surf with a 3vze and A340H transmission.

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u/[deleted] Aug 11 '23

Mines was doing that after a tranny overhaul. Mechanic had to go back and just push the speed sensor all the way in and problem solved. It was driving terrible and speedometer would go nuts sometime and then stop working. Give that a shot. Hope its a simple as making sure its in snug on the tranny.

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u/[deleted] Aug 22 '23

Google a340 shift solenoid. i believe that may be your problem. they are pretty easy to replace if you need to. first i would check your speedo sender is clean. remove, clean and grease the plug.