Blink (a/k/a Flash) Codes – How to. - Historical

DTCs (diagnostic trouble codes) related to the vehicle's braking system can be read using nothing more than a short wire or paper clip. With the car turned off, short pins 4 and 13 on the OBD2 connector using the wire/clip, then put the car in IG-ON (press the POWER button twice with your foot off the brake).

Now observe the blinking pattern of the ABS warning, brake warning, and slip indicator lights in order to identify the DTC. If there are multiple codes, they will blink out in ascending order. Each of the indicators may blink out a different code so note that carefully. The two-digit codes obtained correspond to full DTCs that can be looked up in the repair manual.

I don't think this shows historical codes, though. And to be able to check codes from all other ECUs, you really do want Techstream.

This Prius Wiki page has been created so that there is a convenient place to direct people, rather than regurgitate the same information over hundreds of posts.

The original thread (with thanks to Mr. F) from which this information was taken can be found here:

Check Hybrid System | Post #8 |PriusChat