So I've got my 89 4Runner with 3.4 swap running (idles and low speed are fine, but won't rev past 3.5K and has crappy power, feels like its running out of fuel as revs build), but I cannot get the OBD2 connection to work. ECM and wiring is all from a 1996 4Runner 3.4 MT. My problem is that I'm only getting .41 volts at Pin 2 (Signal wire from ECM). I think I should be getting around 5-10 volts (the FSM doesn't specify a voltage). I traced the signal wire from the OBD2 port back to the ECM and with only the E9, E8 and E7 plugs connected to the ECM I have 8.93v coming from pin E9-19. As soon as I plug in E6 (26 pin plug), then voltage drops to .41. I'm stumped. Is the ECM faulty?

Any help is greatly appreciated. I've verified 12 volts to the OBD2 port (pin 16) as well as continuity for grounds (pins 4,5). I've tried three different code readers.

 

For anyone else with this problem...another member verified their readings as .40v for pin2 as well, so I think it might just be my reader. I've tried three so far....so if anyone has a 96-97 4Runner please let me know what reader is working for you.

 

I use a $20 one off of amazon with no problems. Connects to my phone via Bluetooth, and has little lights on the side that light up when it's physically connected regardless of whether the truck is on or not.

Bafx Products Wireless Bluetooth Obd2 Scanner Diagnostic Code Reader & Scan Tool for Android Devices Only - Scan, Reset & Clear Car Check Engine Light

 

The issue ended up being my swap harness wiring. Nothing to do with the OBD reader or OBD wiring. My STA wire to the ECM was providing signal all the time, which it shouldn't have been. That's all it took for the OBD2 not to work. Once that was fixed, the OBD2 connected right away.