Hey everyone. I have an odd issue with my 2008. I’m a mechanic with 10+ years experience but I’m a bit stumped. (and would love some help) So Figured I’d turn here first before going crazy with trying to diagnose the issue. I can’t connect my obd scan tool, been an issue for bit but car ran fine. Then red triangle today. (May/14/2025) Found the 7.5A OBD fuse blow at first, replaced it and red triangle went away so reconnected scan tool and still no communication with car. then red triangle came back up. Checked the OBD fuse again and NOT blown this time. Try a few times to reconnect and manually enter VIN etc. no luck. I have to try my OBD break out box tomorrow to see what pins in the OBD port are working and which are not. But again before I go crazy and spend hours going through diagnosing this I was hoping someone else maybe had this issue and can let me know what the fix was for it
On right track they're have been a few issues . I had same in gen3 for days after engine change it just started working again about 5 days later . Still do not know what twas. There is a section in the manual about troubleshooting the OBD2 port.
Did you try the OBD tool on another car, or another OBD reader on the prius? I had a cheap one die years ago.
I've had cheap scanners that won't even recognize the car plugged in and does nothing just sits there go to a General motors car and it fires right up the scanner that is got a few sitting around here that can do this today but they're real old apparently he's plugging it in and it's doing something.
Verify that the OBD2 dongle works on another car. Inspect the OBD2 port connectors for corrosion or other physical damage. Did this OBD2 dongle ever work with that port? I had one dongle which simply did not fit one of our cars (don't recall the combination), nothing was broken per se, but the sizes were just slightly incompatible. Follow the wires up from the OBD2 port and look for aftermarket modifications - sometimes cars bought used have trackers installed there, which can later cause electrical issues. Follow the manual section on OBD2 problems.
Do a pin drag check of the data link connector terminals. Verify good grounds at pins 4 & 5. A Gen2 uses CAN at pins 6 & 14 for scantool communication to ECM, hybrid control, & high voltage battery ecu's. Pin 7 is SIL (ISO 9141-2) and is for scantool comm to everything else - the ecu's on the BEAN bus (Toyota LIN) go though the gateway module. Posted via the PriusChat mobile app.
