ErockTN711

Hey all,
I have scoured the interwebs trying to find a similar situation to mine, so thought I might get some advice here...
Dealership found code c1391 in the history on wife's 2010 RX 450h after all the ABS warning lights came on and then went back off.
Quoted $3200 for the actuator and brake booster.
I'm aware that this is a known issue that was briefly covered by the assistance program (sent letters out late 2020 and ended program December 31st, 2021).
​​​​​​As I mentioned, in our case, the warning lights went off after a few days and did not come back on.
There are no noises and everything having to do with the brakes feel completely normal.
Can I be confident that the system is bad even though the lights are now off and everything is working normal?
Would it be advisable to decline the work and see if there's any issues that arise moving forward?

Thanks in advance
E

RX in NC

I would call Lexus Corporate and ask for that program assistance to be applied to my case. If they decline, I would wait to see if the issue returns. If it does, I would go to a well-respected Toyota / Lexus indie shop for their opinion and estimated cost before taking any repair action. Lexus dealership service costs are insane these days. No way will I go back to the dealership with my wife's 2015 RX350 unless it is for warranty work. Fortunately we have a couple of honest, fair, long-time-in-business indie shops in our neck of the woods that can handle anything I do not choose to DIY.

ErockTN711

I appreciate your advice.
Between that code, and all the other things they said we needed (CV boot, TPMS sensor, spark plugs, tires, air filter, coolant flush and AC cabin filter) they quoted us $7,632.49.
So far, they are denying payment at corporate, although I'm still trying to climb the ladder with supervisors, it's not looking good.
I'm wondering if the situation is possibly dangerous even if the lights are not on and everything seems to be functioning or if I should be good to go if they stay off and no issues arise?

RX in NC

As I said, if the brake system is functioning normally now, I would wait to see if the issue returns. But I would also drive very carefully at all times and automatically increase my following distance for the vehicles in front of me. Only you or your wife can determine how much level of risk you are willing to take. At least find and speak with a good indie shop so you will be prepared if Lexus denies you any assistance in this matter.

By the way, how old is your 12-volt battery? Failing batteries often throw spurious OBDII codes and illuminate the dashboard warning lights.

ErockTN711

The 12v is fairly new; shouldn't be the issue.
Just spoke to an indie shop, very transparent and thorough guy. Pretty much same story saying ultimately they would have to get the parts from Lexus and probably wouldn't be much better on the price.
Maybe a little lower on labor.
In terms of risk, he pretty much said what you said...
​​​​​​Something might happen, something might not, but with braking systems clearly it's always a bigger risk to ignore.
Guess I'll wait for that call from the corporate supervisor to likely turn down the good will appeal and then just bite the bullet on it.

703

Let’s simplify this.

what’s your brake fluid level? Is it still full?

You can do an active test of the brake accumulator yourself using Techstream, don’t need to rely on dealers who just wants to replace parts without testing which is silly.

also, sounds fishy they want to replace the CV. What’s wrong with it?

ErockTN711

Appreciate your reply
"Front axle shaft CV boot, r&r" is what it says so assuming the boot is cracked or something. $702.62
Didn't ask because I wasn't planning on having them do it.
Brake fluid reservoir is full or close to it.
Don't know anything about Techstream but I'll Google it...
It's currently at the dealer and we have a loaner, haven't asked them to do the work yet.

Roscol

If there are no signs of fluid leakage anywhere, I would wait to see if the problem comes back.

If you’re not hearing the pump pressurizing the system every 30 seconds or so, then the system isn’t losing pressure.

If the code returns, first thing I would do is a full brake bleeding to see it resolves the issue. After that, parts replacement.

Xennial

I bled my brakes, but I still hear the pump pressurizing every 30 seconds. So I take it I should probably replace the parts?

salimshah

Which parts?

If you are not loosing fluid, most likely the pump has an internal leak and that might need replacement. Expensive part and should you throw a part and hope to have solved the problem or pay a shop to diagnose and replace?

If you plan to DIY, make sure you have the tool/software to bleed the new system.

Salim

Xennial

I had this problem with code C1391 at 164k miles or so. I found some answers in the LS forum, but I watched this video to get an idea of how to fix.
Since I was having the exact same issue, I followed suit and wanted to replace both the accumulator and actuator as recommended in the video since bleeding the brakes didn't fix the issue. I tried getting a quote from Lexus, but they never got back to me for the total price. I did get a quote for just the accumulator for around $1000. I got a quote from a mechanic I have gone to in the past, and they quoted me for the same part $1400. JUST THE PART. Plus about $600 to install. So I went to bell lexus' website in Scottsdale, and the part 47070-48060 was $786. The actuator part 44050-48320 was $1179. So for $2000, I got both parts. I found a local, mobile mechanic that was willing to come to me an install the parts, and you can see that process in this video:
It has now been 3 weeks, and the lights have stayed off and everything seems to be working as it should.