Brake, ABS, and traction lights

Yes - retrieve the trouble codes from the braking computer and post them here. Even if they were, in some way, spuriously caused by the T-mobile gizmo, without knowing what trouble it thinks it has, we won't know how to persuade it otherwise. Some brake codes are held in nonvolatile memory and will not be erased by simply pulling fuses.

The easiest way to get the brake trouble codes is with a (working!) scantool, for many people a Mini-VCI with a laptop running Techstream. But if you don't have that, there is an easy way to get abridged, two-digit versions of the codes, using only a short piece of wire. You count while they blink out on the brake, ABS, and traction lights.

-Chap

 

you could try disconnecting the 12v for a minute to clear the codes, and see if they stay off.
some have had obd issues, but they usually clear when the device is disconnected.

 

Ok, 42 and 45 look familiarish. Caution: don't put too much stock in my memory here, because it would be best to look them up in the manual, and my techinfo access isn't paid up at the moment. Maybe somebody has a downloaded copy of the brake section to look at.

In my scribbled notes, 42 and 45 are two of the codes that will be shown when the brake computer wants to re-learn its linear solenoid response curve. You can tell it to do that with Techstream and a Mini VCI, or, according to my notes, also with a jumper (though I've never tried to do it that way).

For that, the car needs to be parked somewhere level and with the parking brake released, steering wheel straight ahead centered. Then you want a jumper between the TS and CG terminals (not the same as what you just did, that was TC and CG), then turn the ignition ON (just ON, not READY, that is, two pushes without touching the brake).

If the car really did want to re-learn the linear solenoid, it will then start blinking the yellow brake light about once a second, and making a sequence of odd brake noises, where each one builds up and lets off a little more pressure than the last. When it gets through the whole business, the blink goes from once a sec to four times a sec, and you turn the ignition back off and remove the jumper.

I think if the car didn't really want to re-learn the solenoid behavior, it just won't do anything special when you turn it on that way. (Then you'll just have to look in the manual to see what else those codes may mean.)

Note looking for the TS terminal, different sources give different pin numbers (they moved it between Gen 1 and Gen 2). In a Gen 3, TS is pin 12. 12 12 12 12 12 12 12.

-Chap

 

Glad to hear it worked and just needed the linear solenoid init. I'm also glad to know the jumper procedure worked; I've done the init through Techstream before, but had not tried it with the jumper. I don't always have a laptop and Techstream in the car, but I pretty much always have something to use for a jumper.

One way the linear solenoid values can be cleared is by a sequence of pulses on the TS pin. I wonder if the gizmo you plugged in is generic for lots of different cars, and somewhere in its connecting to the car, could have put pulses on that pin, probing for something else. We were seeing stuff like that happen (but other pins involved) with early ScanGauges in Gen 1s.

By the way, the information I presented up there is all in the repair manuals at techinfo.toyota.com (I know, 'cause that's where I learned it), for those times when nobody who happens to know is on PriusChat right when you need it.

Cheers,
-Chap

 

I used a ScanGuage for about 4 years. About 2 years back I started getting "Check Hybrid System" warning plus various brake system warning lights, plus a strange "return to basics" feel in the brakes. With the latter, it'd first feel like the brakes had been lost, but then you realize they're still working, but just not as responsive. Strange feeling.

Anyway: several visits to the dealership later, and coming up on a year back now, the last mechanic that checked it out noted that his techstream connection could be broken, by just jiggling the connector. He suggested that the constant weight of the ScanGauge obd connector might be causing problems.

I decided to disconnect the SG at his suggestion, and have had no further problems. That's not to say it is the cause, but so far I've had no repeats. Something to try?

 

The OP had previously installed some T-mobile OBD gizmo, which might have been the culprit.

My ScanGauge has been plugged in for nearly a year now with no ill effect, and it was plugged into my Gen 1 for about eight. (But to work in a Gen 1, it did need an alternate cable, to prevent it from putting random signals on a different pin, that in Gen 1 went to the airbag ECU...)

-Chap

 

Hello,
My brake light, ABS light is on and the car keeps on beeping. Can anyone help me how to fix this problem?

 

I have had many OBD2/ECU issues with my 2011 Prius (piece of crap). I would need a white board and two hours to explain it all. In short, Toyota Prius 2010-2014 are a nightmare and Toyota somehow feels they are not responsible in the least.

Anyway, thanks much for the OBS paperclip trick. It worked for me too. I was able to clear the bizarre OBS 'error' that the CA Smog Station OBD device created for me.

You may have actually saved a life! I may have committed hari-kari were it not for your tip. (I would put a smiley face here but I am not really kidding all that much.)

Anyway, I have never been able to pin down Wth pins are what for the 2011.

Pin11 is unpopulated but I see things that say it should be 'ABS'??
Pin12 is TC: Toyota Control? That right? A techstream-only thing??
pin13 is pink w/Blk: I have no idea what this is??
Pin15 is unpopulated: Is that correct?
Which pin is 'TS' (Toyota Status?) Is that pin13? Is there a link to something that explains reading status codes from ABS?

The rest, I think I get.

BTW, I found that my ground chassis had what I thought to be a boarderline high reading (as in a nearby short?) so I ran a homerun ground wire to the 12v batt. Car immediately worked much better and Techstream could then communicate (it could not before). I offer this tip in hopes of sparing the life of a fellow death spiral 2919-2014 Prius owner, just as mine has been spared. At least until next week's fresh Prius hell, that is Andy

 

Did anybody check the state of charge of their auxiallry battery? Mine shows only%65 charge and brake abs and traction light on. I’m thinking it might be related to that soc.

 

In this thread, the real ticket has been to read the codes and see what problem exists, then solve that. There are dozens of possible causes for the same lights on the dash. For example, the original poster found out that the codes meant a solenoid learning procedure was needed, and did that procedure, and the lights went away.

Now, for whatever particular problem you are having with your car, could it possibly be related to the condition of the battery in your car? Sure, you could give that 65% charged battery a good charge and see if it helps. If it does, you'll have found an easy fix for the particular problem you are having.

 

My prius 1.8 2013 127900 km driven is showing Traction,ABS,Parking Brake and (!) Lights on dash.I got scanned and code C1391 is shown.Lights are not permanent but often get off for some time and then come on again.Average fuel consumption has dropped down to 15km/litre from 23.Brake is still working but needs little push than normal.Please help

 

Two things: 1. depending on what was used to scan for codes, there could be other codes set in the car that were not reported. Toyota's Techstream software is reliable for reporting all the codes that are present. Other things, not always so much. So, it could be helpful if you mention what was used to read the codes.

2. C1391 pertains to a problem with the brake system pressure not holding up as well as intended. There are about three pages of troubleshooting information in the manual (more info) to help find out why you have that code and what to do about it. There is also a possibility, with a 2013 and 127900 km, that a Toyota covered repair program will apply to you, though I do not know the details for Pakistan.

 

Chap,
Thanks for this info!

I had a previous intermittent C1344 code that I could clear with the techstream system or by jumping TC (OBD pin 13) to pin 4 and pumping the brakes. I finally got around to bleeding the Rear Left brake and all was well for about 3 days.

Then, coming down the ramp in a parking garage, the brakes got weird and the ABS, brake etc lights illuminated. I tried the TC to ground jumper, but no dice.
When I got home, Techstream pulled up C1203 Engine Control system comm circuit and C1345 Not learning linear valve offset.

Neither of these codes cleared via techstream. I thought I would need to buy a used brake control module. It’s good I searched and stumbled on this thread.
Jumping TS to pin 4, then IG on and waiting for the relearning to take place worked! All of the codes are cleared and braking is back to normal.

Thanks!

 

We have an almost-sort-of-tradition here on PriusChat where someone will post about some lights being on and most other responses will say aww, gee, looks like you'll have to replace the XXX part, where usually the XXX part will be the most expensive thing that could ever cause those lights to be on.

It makes me happy every time somebody takes the time to read the codes, find out what the car wants, and do that, sometimes even for no parts and no money. Good work!

 

Hi ChapmanF, Any chance you could provide the 3 pages of troubleshooting that you mention above in ref to the C1391 DTC? I could not get any DTC using a brand new carista UBD2 so I had to take it to Toyota (they charged $50 but gave me a loaner car for 24 hours). They told me they needed to change the Brake Booster-Master Cyl and the Brake Booster Pump Assy which totaled about $$1750 in parts and then $1800 for labor. If I had those 3 pages of trouble shooting I could at least check those off the list before buying those 2 parts that Toyota said I need and I would be installing. Thanks!