Picked up a 2010 model with 150,000 miles and no apparent issues until my wife reported that the brakes went to the floor and the dash lights were flashing when she restarted the car after refueling. I had her record the flashes on her phone and was able to explain to her how to clear the codes (she had a paper clip in her purse!) and life was good again until she refueled again and same story … codes 42, 46 and 92. I was skeptical of her connection between the codes and refueling until it happened to me at Costco yesterday. I bought a scanner that I plugged in to clear the codes, but it said “No codes”. So, out came the paper clip and back on the road. Does this make any sense or is it just a coincidence? Thanks, Tim
Tell us how you are reading the codes 42, 46, and 92. Are you using a scan tool? Are they blink codes?
They are blink codes. The 92 is the steering wheel with exclamation point, the 42 is ABS and the 46 is the circle around the exclamation point.
42 on ABS just means to pay attention to the code on ECB ((!)). That's explained here: Blink (a/k/a Flash) Codes – How to. | PriusChat So, 46 on ECB. C1246 code. Not one we see a whole lot of here. Problem with the regulator pressure sensor in the brake actuator assembly. With a scan tool that shows INF codes, you'd get a 201, 202, 203, 204, or 207 (and maybe 424?) pinning down the problem more specifically: That regulator sensor is built into the brake actuator assembly. You also see it in that table being called the "booster with master cylinder" or "skid control ECU", never mind, those are all the same thing (the one on top here): Just don't confuse that "brake booster" with the "booster pump"—that'd be a different thing (the one on the bottom). Because the regulator sensor is built into that actuator assembly, there might not be a lot of clever use for you to make of the specific details from the INF code: if that sensor's bad, the whole assembly gets replaced. But I do notice that INF code 204 could come up because of a problem with the brake pedal stroke sensor, so if that's the INF code you've got I would definitely check that before springing for an actuator. The table above is from the first page of the troubleshooting instructions (there are five pages for that code) in the repair manual. Toyota Service Information and Where To Find It | PriusChat For 92 on the steering light I've got nothing. Seems like their steering ECU still knows how to do blink codes like the old days but they stopped including the blink codes in the manual. Most of the steering codes are C15xy and it wouldn't be shocking for the blink code to match the xy (they all matched like that in gen 1, when they were in the manual). But there's no C1592 code shown in the manual either. Probably best to get your hands on a scan tool that can read the complete code so we know what you're dealing with there.
I will go ahead and pick up a good scan tool. When it throws the codes the brake pedal will go to the floor unless you lightly pump it and then it acts more like manual brakes … until I do the paper clip reset. I’ve actually gone weeks without it happening. Thanks for the great info! I will try and get the codes to reappear next fill up.
Read post #1 and then scroll down to post #37 in this thread, https://priuschat.com/index.php?posts/3246758 You want to buy a scan tool that is capable of communicating with all the ECUs in your Prius.
