Advice on brake booster/master cylinder replacement

First off, I would like to sincerely thank everyone involved in the upkeep of this site, and especially all the folks that post such invaluable information. What a fantastic resource!

Our 2012 V brought up ABS, ECB (!), VSC, and PCS warning lights simultaneously. Jumpered 4 and 13 on the OBD connector and brought up the following faults. (I believe the DTC's listed after are correct, but must admit I found the manual challenging to utilize).

ABS /34 C0215/34 Rear speed sensor L.H.

ECB /62 U0123/62 Lost comm. with yaw rate sensor module.
/94 U0073/94 Yaw rate comm. disabled.

PCS /31 Unsure of DTC.
/41 Unsure of DTC.

My assumption is that, since the three codes I believe correct all have one common failure point in the brake booster/master cylinder-skid control unit, that we are looking at a replacement, especially as it's a known issue and the warning lights came on together.

Would appreciate any advice or thoughts regarding items we might check prior to ordering the master cylinder!

Thanks!

 

Appreciate the link, sadly it appears that our car is excluded due to the particulars of the program.

 

Beyond appreciative of all the constructive feedback, thanks gentlemen!

Tim, there doesn't seem to be a noticeable change in braking performance, aside from the pump running a little more consistently than I recall. Could be simply a heightened awareness on my part. (My son has been driving it primarily for the last year.) On the short drives I've done to assess it doesn't seem to be regenerating as effectively as before.

Mendel, awesome video. Have learned so much from Youtube, thanks.

Chapman, great advice. My son, the computer whiz, has Techstream up and running, just waiting on the cable to further delve into the process. I saw your post in the Gen 3 forum, after starting this thread, that suggested re seating the wiring loom connector on the actuator, will try that this morning, as well as looking at the wheel speed sensor. Believe I have the correct part numbers for my 2012 V, 47050-47180 for the master cylinder/actuator (list $4151 CDN) and 47070-12020 for the pump (list $3967 CDN), if it comes to that. The naming of these parts is definitely confusing, and the prices simply outrageous in Canada. Would source from the US/Japan. Going forward, this would make me think very long and hard before buying another Toyota. I can't imagine a reason for such a huge discrepancy between Canadian and US prices other than gouging.

Matt, thanks for the overview of your experience. Certainly removes some of my trepidation about approaching the task if it does come down to the actuator. Concern I have is with corroded brake lines after so many years with salted roads here, but it is what it is. Appreciate the advice on bleeding and the scan tool if the knock off Techstream doesn't work. No problem paying for the official version if it's necessary too, and we know we'll only need it for the day. I've done the brakes almost annually, water pump, plugs, EGR cleaning (that was fun), coolant, and trans. fluid as well. Also the parking brake cables, they were almost as much joy as the EGR.

Best, Andy

 

It seems as if the issue was the LR wheel speed sensor. Checked the continuity last night (as was possible with the hub in place) and seemed to read open. Changed the hub today, cleared the faults, short drive and the codes haven't returned (knock on wood).

A few thoughts for anyone facing the same issue(s).

Not having had the speed sensor connectors off before it was a challenge. The grey strain relief/retainer/cover thing was filthy, luckily the pigtail was clean inside. Pleasantly surprised given how rusty and dirty the car is. Learned how to remove the cover from this video at 3:21:

Trying to get the meter leads onto the terminals on the speed sensor was likely the worst part of the job. Pulled the plastic covers back on my meter leads and taped them together at what looked like the approximate width of the terminals and felt around to touch them inside the plastic housing. Like playing the game Operation but in reverse with your eyes closed. Kinda, but much worse.

From that point the job was a breeze, as far as dealing with the ridiculous "drum in hat" parking brake ever is in the rust belt. Note: much easier assembling the parking brake with the hub out, then reinstalling the hub.

The hub came out easily using a 1/2" x 2" all thread socket head, nut, and washer to force the hub out, by utilizing the holes in the wheel flange. Placed the base of the socket head (bolt would work too) against the heads of the backed out mounting flange bolts, turned the nut against the wheel flange in a kitty corner fashion and it slid out. Sorry I didn't get pictures but it was two degrees and raining. After shot with "special tool":


Contacted the Toyota dealer to check stock on the hub. Parts kid: "30 on back order." Me (sweating): "ETA.?" Parts kid: "Don't know and don't care." Okaaayyy then. Fortunately a fairly local aftermarket parts supply had one for $100 less than Toyota's.

Huge thanks again for all the great advice folks! Time for a well deserved Guinness.

Cheers, Andy