Need advice with 2006 V6 brake issues
 

The 2006 4Runner (Sport Edition 4WD 4.0L, 208K miles) I recently purchased is turning out to be quite a bit more problematic than I was led to believe (in my defense I did have a supposedly independent local mechanic do a pre-purchase inspection!), on a variety of fronts. I'm trying to work through the various issues, hopefully without having to spend more than I paid for it, and I could really use some help from the collected wisdom here!

In terms of potential cost, the biggest issue appears to be brake related. The mechanic's pre-purchase inspection did not report any brake-related issues. During my test drive, the vehicle stopped perfectly fine and solidly when applying brakes, but I noticed that while at a stop light, I would have to repeatedly press harder and harder on the brake pedal to keep the vehicle from creeping forward. Seller reported that it had always done this (of course!).

After I got home with the vehicle (out-of-state purchase, 4 hour drive), my local mechanic reported the following potentially brake-related OBD-II codes:
C1223 - Malfunction in ABS Control System
C1249 - Open in Stop Light Switch Circuit

For completeness, the other codes are C1201, P0031, P0051, and B1181: I understand that C1201 is essentially the "master switch code", the P0031 and P0051 codes are related to the upstream O2 A/F sensors (I was actually aware of these codes), and the B1181 code is related to the airbag-possible clockspring assembly issue.

Also for completeness, the following lights are on: MIL (Check Engine), ABS, TSC, VSC, TPMS, and Passenger Airbag.

My mechanic believes the braking issue and the C1223 and C1249 codes are caused by a failing master cylinder assembly, and recommends replacing the entire assembly, which apparently lists for about $3,000. I've read a bunch of related threads on this forum, which largely seem to confirm this diagnosis. Given the rather crazy cost for a new assembly, I am wondering whether I should just go for a used assembly, which I can get for about $450 on EBay (I'm currently checking to see the VIN and mileage of the vehicle this was removed from), or even potentially go the master cylinder piston replacement route (there's a thread suggesting that a 2008 owner successfully used 5th gen part 47026-60090 for this) for $50 on EBay and/or just buying a booster pump motor (EBay, ~$300).

But then I read threads on this site about the C codes above, such as this one and this one, that suggested those codes could potentially be cleared by replacing a brake light switch.

Anyone have any solid advice as to how I should proceed on dealing with the brake issue?

To be clear, I'm not looking to DIY this repair - the work would be done by my mechanic, who is willing to let me obtain parts myself. I just don't have the facility/expertise/confidence and/or time.

Any advice would be greatly appreciated!

Personally I would drop the front wheels and check the calipers for frozen pistons and then do full brake flush including the whole procedure to bleed the brake assist and see if it makes any difference. Thats about an hours labor and $10 in brake fluid, it may well not fix it but it's worth a try. When I bought my 07 it had ran and braked fine but when I pulled the calipers 3 of them were frozen, I replaced them with remanufactured units but had to bleed the brake assist several times before it felt right. Before I did that it would creep forward at lights and braking was not great, really grabby.

Thanks. That may be worth a shot! Only issue is that frozen pistons probably wouldn't cause the code, would they?

Concerning the codes for your brakes....

"After I got home with the vehicle (out-of-state purchase, 4 hour drive), my local mechanic reported the following potentially brake-related OBD-II codes:
C1223 - Malfunction in ABS Control System
C1249 - Open in Stop Light Switch Circuit"

I do believe replacing the brake switch will solves the issue causing those codes.
Read this linked topic which had the same codes as you have and replacing the brake switch solved the issue causing the codes, the brake switch is relatively cheap and installing it only takes a few minutes and is the most common failure that would throw those codes, well worth trying before trying to replace other more expensive parts.

http://www.toyota-4runner.org/4th-ge...223-c1249.html

Frozen calipers are a very common problem on 4th gen 4runners, so I would definitely investigate that before diving in further into more expensive stuff. Always check the cheap and easy stuff first.

Any time the CEL (MIL) light comes on, so will the VSC and TRAC lights. The reason is that Toyota can't guarantee proper operation of the dynamic stability system if the engine isn't running properly, so they switch it off.

Thanks for the reply! I did read that thread, and I totally get that this is an inexpensive fix, but is there any chance that a faulty brake switch is causing the pedal to creep to the floor at a stop light?

No there's no chance of the switch causing that, but whatever is causing the pedal to creep wouldn't cause it to throw the C1249 code. IMHO

The switch is an electrical issue, the pedal creep is a hydraulic issue.

As previously stated, your best bet is to go through the system, bleed everything and make sure your calipers are functioning as designed. It takes a while to get all the air out of the system. Check for leaks as well.

It could be the master cylinder. I'm a new T4R owner but I've been working on cars all my life so I'm no stranger to getting my hands dirty. Is the master cylinder a common issue with these? Sucks if it is... "IF" that is the problem I would shy away from buying a used part from eBay. You don't know what you're getting, and if it's a common problem it's probably a ticking time bomb.

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Need advice with 2006 V6 brake issues
 

The VCS/TRAC lights could simply be the gas cap seal. Sounds stupid but it is related some how

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Thanks to everyone for their helpful input! Based primarily on the continuing pedal creep at stop condition, I've decided to go ahead and get the brake master cylinder assembly replaced with a used unit supplied through my local repair shop that carries a six-month warranty. Cost is about the same as what I could find on EBay, and warranty is better.

I'll be sure to update this thread to let everyone know the extent to which this solves this particular problem.

Every time I get a fault code those lights come on. I think it's part of the system to get your attention. Once it was the gas cap, and twice it's a P0012 code for my oil control valve.

UPDATE - All problems solved!
 

Thanks again for the help from all who chimed in to answer my questions. As promised, here is an update (sorry for the delay). Short answer - all problems solved!

Brake issue (pedal creeps to floor with sustained pressure) and
Code C1223 - Malfunction in ABS Control System.
- Replacing the master brake cylinder assembly with a used one (6 mo warranty) worked. First tried flushing and bleeding; that did not work. Toyota part number is 47025-35070. Part cost: $465.

Code C1249 - Open in Stop Light Switch Circuit.
- Replaced brake light switch using Duralast Stoplight Switch SW7249. Part cost $31.99.

Code B1181 - Open in D Squib (2nd Step) Circuit
- Replaced clockspring assembly (Part 84306-60080) using part purchased from Ebay seller jp-genuine (link: GENUINE TOYOTA LEXUS OEM NEW AIR BAG CLOCK SPRING SPIRAL CABLE 84306-60080 | eBay). Part cost $39.44.

Code P0031 - Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 1 Sensor 1)
Code P0051 - Oxygen (A/F) Sensor Heater Control Circuit Low (Bank 2 Sensor 1)
- Replaced fuse (not sure which one; will ask mechanic). No charge.
Apparently this resolved the above codes, but resulted in a P error code for Bank 1 Sensor 2 (passenger side downstream).
- Replaced Bank 1 Sensor 2 oxygen sensor with Denso Part 234-4260. Part cost $91.99.

- Following the above actions, the C1201 code disappeared, and all the various warning lights also no longer illuminated.

Nice followup and it will no doubt help somebody down the road. Congrats on getting it fixed!