Master cylinder Replacement

An independent mechanic swindled me on a brake master cylinder replacement in 2020. He charged for full replacement but only replaced the booster pump portion with a used part with warranty that has since expired. I’ve had an abs code and warning light since then but the car has been drivable even though I could hear the booster pump every 10 seconds or so. The mechanic has since been fired from the shop. The owner apologized to me for the problem and offered to install the brake master cylinder for $300. Being tight on money now and foolish, I decided to take the diy route. Big mistake.

Recently, I did the gen 4 into gen 3 engine swap. After getting the engine sorted out I decided to replace the master cylinder a.k.a actuator using the thinkdiag dongle myself. The results are rather odd.

The thinkdiag scan tool was able to bleed the brakes and actuator I guess. I still had to pump the brakes to bleed each one plus the actuator. Thinkdiag deleted the memory but did not relearn anything. The abs warning lights remain.

A new issue arose in that the brake lights are permanently on. I’ve had to remove the negative pole on the battery when it’s parked. Another extraordinary thing is the car IS braking properly.

Thinkdiag was contacted and they gave instructions on how to reset the memory and relearn the actuator’s solenoid valve, etc. That has not worked to remedy the issue.

There is a step in the scan tool process where the ignition has to be on but the engine not in ready mode. For some reason, the ignition button goes directly to ready when pushed without pressing the brake now.

if I unplug the battery and start the car it goes into ignition with ready mode off. If I try anytime after that it goes directly to ready mode.

A stealership appointment was the last option to fix the issue. The service department was unable to do anything with tech stream. They didn’t charge me for the diagnostic and politely said, “good luck,” handing me the key at the door. They wrote a report saying the install was faulty and caused everything. I asked them to perform the work and they said they didn’t want to because there are bolts and such missing from the engine swap(three are missing from the air box)

I wonder if anyone else has had similar issues with relearning master cylinder? My only recourse now is to confirm the new part was not faulty from Toyota. No other mechanic wants to touch the car because of the swap traces.

 

I might’ve put the spring on the pedal in the wrong spot or the bolt and pin in the wrong hole on the pedal arm. That would explain the brakes staying on. Codes I’m getting are with the thread.

 

Thinkdiag support: “
Hello sir/madam,

After we confirmed, your car is support. Please follow the steps: Toyota> Prius>2010>ABS(Anti-lock Braking System)/VSC(Vehicle Stability Control)/TRAC(Traction Control System)>Special Functions>Brake Pad Replacement( Operation Guide). If there still are any problems, please provide us a screenshot or an operating video, thanks. ”

i initially thought it had to do with the scan tool but the dealership couldn’t get it to relearn even with tech stream.

 

It was ordered online from Toyota at a “dealer discount” because that particular dealership is pretty far away from any major cities. I confirmed it was the correct fitment prior to picking it up(2 hour drive) and it was ordered with the 2010 vin number. The dealer is blaming install for the part not working, if I was them I’d do the same. Hey the coffee was too hot, right? Put a label on the cup that says that.

I did retain the gen 3 egr and intake. I’m still occasionally getting an evap gross leak code(major problem), egr, and cat code unrelated to the abs obviously. Seems like the catalytic converter is dirty from when the head gasket on the 2010 motor blew. A mechanic told me it’s probably a leak in the vacuum pump. I don’t know. I put cataclean in it. I’m hoping burning 30 bucks a few times will help keep it down till I can troubleshoot it more. plan on changing the gas cap since the gasket feels worn. I read threads and watched videos about smoke tests and such. Sounds like a good issue to punt to a mechanic….which I should’ve done with the master cylinder! Ah! I digress.

Unmanageable….well, more like unmotivated. My local dealer charged me 500 bucks to diagnose the morning/cold death rattle and told me they couldn’t figure out what it was but requested another 600 to keep tinkering with the engine. Few videos on YouTube and finding Priuschat via google told me it was the head gasket Within an hour. Their rejection of the master cylinder work was a mercy.

 

So you’re saying, if I use a scan tool following the tech stream procedure(if it has that capability) to bleed the brakes and actuator again code c1451 will clear? Safer bet take it to the dealer and ask them to do that? Then all other calibration/relearning will be able to be done?

 

Oops

 

I hear ya. I gotta figure out the ignition on/ready off problem first to get to the bleeding. I’m wondering if the zero down or ecb invalid will scramble that. Stuck till then

 

Getting the following codes from abs

c1203 ecm communication circuit

c1345 linear solenoid valve offset learning undone

c1392 zero point calibration of stroke sensor undone

C1451 motor drive permission malfunction

U0073 control module communication bus off

0123 lost communication with yaw rate sensor module

U0126 lost communication with steering angle sensor module

u0124 lost communication with lateral acceleration sensor module

u0293 lost communication with hybrid vehicle control system.


looks like the paper clip pin jumper 4 to 13 pin made me screw things up more.

 

Dealer told me “ replace the brake booster, that’s one of the problems causing the codes. You need to replace both parts in tandem” He also said they would still have to trouble shoot why the brake lights stay on and the issue with communicating with the ecb. The technician vehemently stated he would not perform the bleed procedure because “it will not get rid of the c1451 code.”

They want 2200 for labor.

 

The master technician at the dealer recommended replacing the brake master cylinder and the brake booster pump thus doing what I wanted (making Toyota admit in writing the part might be faulty). Booster pump is used and under warranty so if it needs to be replaced, fine! There’s reasonable cause to ask for the warranty to be filled on the master cylinder now. Not trying to be dishonest in any way just simply asking the dealer each time to install the part again and bleed it according to the manual with tech stream.

These guys don’t know how much I respect them for their expertise and hard work. I mentioned all the info in @ChapmanF posts. I think that pissed them off more because they think I’m telling them I know more than them or something. To be clear, I don’t! but Priuschat is a wealth of knowledge.

 

Is there a post with the bleeding instructions from the manual? @Mendel Leisk ? I have a feeling I did it wrong and I should just try again.

 

The thinkcar thinkdiag dongle scan tool has two sections that show bleeding and ABS as well as actuator replacement. I think my error was in telling my dad how to pump the brakes. need a video showing someone doing the whole operation. Saw one of two guys in Texas working on an Avalon but their scan tool gave more info on how to bleed. It appeared to be a standard Toyota bleeding with a new master cylinder/actuator.


wondering if I can subscribe to tech stream for three days and connect to the Bluetooth scan tool I have instead of a mini vci. Gonna try with my laptop. Maybe on my phone? anything beats paying the dealer.

maybe removing both poles on the battery will reset the brake lights? Only been removing the negative.

 

Thinkdiag supports sae j2534. The laptop located the Bluetooth connection last night. just need the drivers and a three day subscription to tech stream to try again now.