Hello Everyone,

I purchased a 2011 Lexus RX450h to use in our family, after driving an RX350 which I loved, and I do like hybrids!

I purchased it sight unseen (I know its bad but there is a cost factor factored in), it had slight front end damage that I will repair. But I do have a little situation that I was hoping one of you can help me out with.

ABS system.
When I got the car, the ABS/VSC/Brake light were on, and I was getting "Brake Malfunction" message on the dash. The pedal was soft and did not have any pressure in it, you would have to really push the brake hard in order for it to stop.
After some inspection I noticed that the ABS module did not have the harness plugged in for some reason, strange. I plugged it back in, started the car and cleared the ABS DTCs.
Now when the engine starts, the brake pedal pressurizes (goes up), and there is a whine coming from the ABS unit are when it does so (system building pressure). Then shortly after the pedal falls again ( the system depressurizes). It keeps repeating this cycle.
I have pulled the DTC codes and I am getting codes C1246 "Master Cylinder Pressure Sensor" and C1365 "Accumulator Pressure Sensor".

Before I do any further digging, will anyone have an idea what can be causing this? I did extensive research on the web to try to find an answer, but all I was able to find was some relative information from other toyota hybrids that led to the conclusion that the ABS module needs replaced. I would like to try to put it off as a last resort.

Any input would be appreciated. Thank you for the time!

 

I think they scammed you and you have a serious expensive problem to deal with here. You need to conduct a professional more sophisticated diagnosis to correctly identify the issue before throwing money are replacing expensive brake system parts that may not be needed. However, I suspect they unplugged it because either the ABS or electronic brake force distribution module or some Sensor or some related componenet are broken, and all are expensive. Pulling codes is only the first step in diagnosis and does not always identify the failed part. It needs a skilled tech to do some investigative detective work, deduction and deeper digging.

It may require a Lexus or Toyota dealer or hybrid specialty shop to check it out as the brakes are different with the electronic regeneration brakes doing most of the work.

 

Thank you for the input. This scares me a little bit but

I purchased the car off an auction where the car was sold by an insurance company. The car had something like a tree fall on the RH fender area. I know the issue was not addressed by the insurance company, so the car was not sold because of that problem, it was the part of the loss.

I did not check the fuses yet. I will do so when I get home. I will check the wiring again.

I will call some local hybrid shops in the are to try to consult with them.

 

For starters, this should have been in hybrid section.
Next. Toyota hybrids had recall on one of those brake components. I keep forgetting, which one though, accumulator or actuator.
Otherwise, you need to run techtream diagnostics on it, to pin point exactly what is wrong, and fix it. As is, vehicle is dangerous to drive.
It's drive by wire, brake by wire car. Electronics, you know. At toyotanation, in Highlander Hybrid section, there are write ups how to replace accumulator DOY. Not bad cost wise then.

 

ukrkoz thanks for the input. Sorry to post in the wrong forum.

I am a DIYer myself so I would prefer to explore all options myself prior, I have to admit that this is a super complicated car.

I do have good news. I went to inspect the wiring, and noticed that on the ABS module, there was a pin that was slightly bent. I straightened it and plugged it back in. Deleted the DTCs and the abs light went off. The brake pedal feels normal now, and car stops as it should.

I will of course do some more extensive testing for safety, but I think I am going on the right path. I will post updates in the thread.

 

Tskyy,
hope that was it and it's a simple fix. Got to wonder why the pin was bent in the first place. Do you have techstream to run some abs diagnostics?

 

I believe it came out during the fall or something.
I have ordered techstream and will run all diagnostics to make sure everything is square.

Thank you,