Check Hybrid System ...But Starts and Drives to 24mph

My 2010 with 220k just threw up its first "Check Hybrid System" warning. No amount of unplugging the 12v battery and letting it sit, nor Starting the car has reset or removed the warning. I had to get a ride home...in a Tesla.

This all started after a hard acceleration with a fair amount of wheel spin. Immediately there was a clunk, a beep (from traction control) and "beep beep beep" from the Check Hybrid System warning. I then limped it to a friends house, with very little power, only able to go about 20-24mph with ICE engine revving its heart out.

Having previously used Dr. Hybrid, it said the battery was actually in good condition, and we've never had any issues with the hybrid system.

The car is our "beater" and I drive it hard.

Accompanying the Check Hybrid System warning is the "Yellow Triangle of Death", the VSC warning light (Traction Control) and the Check Engine Light (due to a bad catalytic converter...it's been on for a year now, I just ignore it).

The car starts fine, immediately fires up the ICE, and drives up to 24mph...at which point it's as though the transmission isn't "shifting". Yes, I know, these CVT transmissions don't have gears, but still, it's like the transmission is kinda "stuck" in its lower range.

The car starts and drives fine, and because as of this morning, the car was running great and giving no indication of any issues with the hybrid battery, I don't actually think the problem is the Hybrid battery. My guesses are: Inverter or Transmission.

I hope to pull the codes via Dr. Hybrid next time I'm with the car (it's an hour away) and hopefully get a better idea of what's going on.

In the meantime, any guesses?

 

Codes are as follows:

P0A94 - Likely IPM Failure
P0171 - O2 Sensor Bank 1 Too Lean
P0420 - Catalyst system efficiency below threshold (Bank 1) - this is likely because my cat is trash. Burning 1qt of oil every 1
P3190 - Poor Engine Power

Dealer was trying to play coy by saying "it's got a lot of miles on it, so it could be a lot of things." Then I said "well it's throwing a P0A94 so its probably inverter related, and I know there is a recall for the IPM." Then they switched to "well we'll run a diagnostic to confirm that, and if its the IPM, we won't charge you for the diagnostic."

 

So, the dealer has agreed to fix the IPM/Inverter as part of the 15 year warranty recall on that part/system. Hurray!

But, they've also "discovered" a brake master cylinder issue. An issue I had never gotten codes or noticed any issues with previously.

The dealer has been trying to convince me that I should absolutely not drive this vehicle off the lot because of the codes concerning the Master Cylinder Leak. They say:

"The brakes could fail catastrophically with no warning. We've had it happen here at the dealership."

I'm skeptical.
1) Never had any brake related codes come up in my owning the car for the last year.
2) Never had brakes leaks, or disappearing brake fluid.
3) I get the feeling they really want to charge me a $100 "Diagnostic Fee" so they aren't eating the entire cost of the IPM failure warranty.

Is there any way of my validating their pointing to this Master Cylinder Failure without TechStream? Will the brake system throw another type of code? If the Brake Accumulator "ABS Assembly" does fail, will it do so catastrophically as they suggest?

 

Yes. My reasoning was to provide more elaborate details of my experiences to other users who may have the warranty on the inverter but also sees other codes come up. In case my brake related codes are a fluke.

 

So I got the car back from the dealer.

The brake related code they pulled was "C1253"

However, I'm not getting any "blinky lights" or CELs as of yet (maybe an hour or so worth of drive time.)

I'm going to drive it more and then pull the codes and see if it comes up.

One thing is apparent - the IPM Warranty Recall Fix has negatively impacted the cars "Power Mode". Definitely not as zippy as it was previously. Oh well.

 

It's interesting because the work order states "per TSB, replace the brake booster with master cylinder and the brake booster pump assembly" - that sounds more like they wanted to replace these brake parts not because they HAD failed, but because they MIGHT fail.

 

No, only the IPM recall.

The wanted me to spend $2500 to repair the brake assembly that aint broke on a vehicle I bought for $700.