ABS Traction Control ((!)) - on off randomly

Hi all.
This one has me scratching my head. I would appreciate any suggestions on how to debug.
Situation:
2010 Prius 161000 km

Last summer the Traction Control, ABS and ((!)) lights went on one day. 5 min. later it went out. A few days later the same thing happened again. Since the lights didn't stay on, I didn't take it to the dealer. The brakes worked but were a bit harder to press. It was like the power brake assist went off.

It didn't come back until yesterday (~ 6 months).
Yesterday while driving on a wet highway (no rain, road just wet enough to get some spray from the car in front) and the lights went on again. I got off the highway and noticed again that the brakes work but are hard to press. Looking to find a gas station to check it out, I drove a couple of stop lights and the lights went out.

Today I took the car to the car wash and after the wash after driving about a half mile, the lights went on again. Again, the brakes work but are harder to push. Pulled into a parking lot, plugged in the scanner and got no codes. Pumped the brakes a few times, started on my way back home (really close) and before I got out of the parking lot, the lights went out again.

I've spent a few hours reading the forums so I know I'll need to figure out the jumper thing but am confused about which of the terminals need to be jumped. I've seen 4 and 12 / 13?? And besides, the warning lights are off again so not sure I'll get any codes.

The car was in an accident (tapped on the back end) a number of years back but don't think that would be related. Last Toyota service was in Nov. and they did a brake service and everything was OK.

What else should I be checking to figure out what's going on?

 

Thanks @ChapmanF and @Dxta . Knowing where to look is important. I'm learning by doing and appreciate the guidance.

I looked at the Electrical layout for DLC3 and it appears that TC = 13 and CG = 4 on L61 (which is the ODB2 connector).
If I orient the L61 with the wider side downward, the wider side of the connector (lower row) is 8 -> 1 (left to right) and narrower side (upper row) with 16 -> 9 (left to right).

What do I search for in the manual to find the procedure for shorting the TC & CG to get the code flashing? Hmm ... have just found this in the manual.

Connecting terminals TC and CG of the DLC3 causes the ECU to display the DTC by blinking the ABS
warning light.​

OK, that is a start. Not sure how to read it though. I'm sure I saw a post but can't find it now. :-(

I put another ODB2 blutooth connector into L61 and am using Torque Pro with the custom Prius PIDs (thanks to all that added the PID info!). I started logging drives with the hope it will collect that code. It doesn't show anything stored though. Shouldn't that be able to collect the brake codes?

Last question for now.
I've been looking at the number of Mini VCI connectors + software out there and am having a problem figuring out which is OK. Is there a post somewhere that indicates the "safe" vendors?

Thanks again.

 

Hi.
It was nice and warm at 8C today so I could try to measure those codes.

This is what I read.
ABS light flashing 33 and 36
Traction Control Light flashing 43
And ((!)) flashing 36

Does this make sense?

I haven't been able to find the codes in the manual but will continue to look.

 

Hello again.

Another update and a couple more questions.

I tried to get to the ABS/Braking ECU but it's so far back under the wipers/windshield, it's unaccessible unless I start taking things apart. The manual is opaque as to how to get to it. I'm astonished that Toyota would make something so hard to get to. I'd really like to check the connectors before I end up at the dealer but I can't get to the damn things. Youtube doesn't have anything either (or perhaps I should say I can't find any). What is the trick here?

The lights are coming on more regularly and appears to be connected with dampness/wet conditions. So to me this has to be a short somewhere in the cable. It's pretty sad that a cable may be defective so quickly (7-8 years).

I spoke to the dealer and they will do a scan of the codes in a few days. If the lights are out, then I doubt they will be able to figure it out. So I may have to take the car for a wash before I go.

The service rep who I spoke with has already decided it must be both speed sensor cables. But he says that to change the 1 or two speed sensor cables, they need to remove the full unit including the bearing assembly. That sounds a bit extreme if the cable is in some way cracked. I checked the manual but I can't make out if the dealer service rep is looking to repair more than necessary.

Can't you just change out the cables?

 

Thanks Chap. I'll update after I visit the dealer.

 

Hi. So the past 3 days have been dry and of course the warning lights went out. I couldn't get them to go on so went to the dealer wondering what they might find.

I have ordered the cable so I can do this better the next time but for the moment, here is what the dealer diagnostic gave.

Error codes are C0210 and C1238. The trouble code report shows C0210 as Rear Speed Sensor RH Circuit and C1238 is Foreign Object is Attached on Tip of Rear Speed Sensor RH.

They checked the wire harness and connectors. They showed me the connectors. They are completely clean and there is no corrosion.

They recommend Remove & Replace Right Rear Speed Sensor Assy. That appears to be removing the bearing & gear/optical component as one assembly. From the manual diagrams it seems to be the correct call. Does that make sense?

Part price is pretty close to buying one online + shipping. Not sure about the 2 hours labour but since I'm not getting gouged on the part price ...

 

Hi @Michael G

I had the dealer replace the rear right wheel bearing about 3 weeks ago and should have updated my post as SOLVED. Yes, replacing the wheel bearing appears to have fixed the problem.

 

Hmmm. I can't see how I can update the post title to add "solved". Anyone know if it's possible?