Recently we’ve got a bunch of warning lights on the dashboard of our Toyota Highlander Hybrid Limited indicating a brake system malfunction and urging us to stop the vehicle in a safe location. The brakes were still working and we were able to carefully and safely drive home. After scanning the car for ABS error codes and doing a quick online search, I realized that the brake actuator assembly failed in our car. Let me share with you how I was able to figure that out and how I got it repaired for free.
According to several official Toyota and Lexus customer support program notifications, certain Lexus and Toyota car models have been reported having brake actuator assembly and brake booster pump assembly internal malfunctions. This issue could be repaired free of charge by the manufacturer if several specific conditions could be verified. The following warning lights will be illuminated on the instrument cluster or information display: yellow master warning light, the red brake system warning light and buzzer, yellow ABS warning light, yellow SLIP indicator light. The brake booster pump could be turning on frequently or working constantly. Unusual squeaky noise can be heard when depressing the brake pedal. In addition, the ABS Diagnostic Trouble Codes C1391, C1252, C1256 or C1253 may be stored in the vehicle’s memory.
The cause of this issue
This condition may be caused by small internal brake fluid leak inside the brake actuator assembly due to improper sealing. Brake booster pump moor might be turning on frequently or without breaking as a result of internal leakage, causing it to wear out prematurely.
Which vehicles does it affect?
This issue has been reported to affect several models of Toyota & Lexus vehicles. As time goes on, this problem may affect more cars, since the issue is most likely to manifest itself in high mileage vehicles. For your reference, here are a list of known affected models as well as customer support program names for each vehicle:
- 2006-2007 Toyota Highlander Hybrid
- 2004-2010 Toyota Prius
- 2007-2011 Toyota Camry Hybrid
- 2016 Toyota Rav4
- 2006-2007 Lexus GS430
- 2007-2011 Lexus GS450H
- 2008-2011 Lexus GS460
- 2007-2013 Lexus LS460
- 2006-2008 Lexus RX450H or RX400H
- 2010 Lexus HS250H
- 2016 Lexus ES350
- 2016 Lexus RX350
I also found the following customer support programs and recalls have been issued to address this problem: ZKC, ZG1, ZJB, ZLG, G0I, GLC, ZE1, 13V-235, 16V198.
Symptoms of a faulty brake actuator and brake booster pump assembly
- Yellow Master Warning light on
- Red Brake System Warning light on
- Yellow ABS Warning light on
- Yellow SLIP Indicator light on
- Check VSC message is displayed
- Brake system warning buzzer
- Squeaky noise when depressing the brake pedal
- Brake booster pump working nonstop or turning on too frequently
- Poor brake performance or brakes malfunction
- ABS DTC error codes stored in the ECU
ABS error code definitions
When brake actuator assembly fails on your car you may one of a few of the following ABS diagnostic error codes. You will need an advanced diagnostic scanner that can read ABS error codes to be able to read these codes. I am personally using this BlueDriver diagnostic scanner (this is Amazon affiliate link), but there are many other diagnostic scanners out there that you can use as well.
- C1391 – Abnormal Leak of Accumulator Pressure
- C1252 – Brake Booster Pump Motor ON Time Abnormally Long
- C1253 – Brake Booster Pump Motor Circuit
- C1256 – Accumulator Low Pressure
What should you do?
Toyota began to notify owners in late June 2019 and will be mailing the owners of affected vehicles over several months. If your vehicle qualifies for the voluntary customer support program, you will receive a notification letter in the mail. If you are experiencing all or some of the symptoms mentioned above, contact your local Toyota or Lexus dealership and make arrangements for diagnosis and (if necessary) repair. If the condition is verified, the dealer will replace the Brake Actuator Assembly and Brake Booster Pump Assembly with a new one FREE OF CHARGE.
Example of the official letter from Toyota
Here is an example of the Customer Support Program / Warranty Extension (ZKC) notification I received in the mail from Toyota Motor Sales USA for our 2008 Highlander Hybrid:
According to the official notification letter from Toyota, the Primary Coverage for our vehicle is active until December 31, 2020, regardless of mileage. After the Primary Coverage, the Secondary Coverage is applicable for 10 years or 150,000 miles from the vehicle’s date of first use, whichever occurs first.
Technical instructions for aforementioned Customer Support Programs can be found in the following technical service bulletins:
Frequently Asked Questions
What if the diagnosis is performed and my vehicle is not covered by the Customer Support Program?
If the condition is not covered by this Customer Support Program, you may be responsible for the initial diagnostic fees and any other repairs you may decide to have performed. Any authorized Toyota dealership can determine if a condition is covered by this Customer Support Program. Your consent is required before any repairs can be performed on your vehicle.
What if an owner HAS NOT experienced this condition but would like to have the repair completed?
This Customer Support Program only applies to vehicles that have exhibited the condition described above. If an owner has not experienced the condition, he/she is asked to tear off the sheet included in the owner letter and insert it into the Owner’s Warranty Information Booklet for future reference.
What if I previously paid for repairs related to this Customer Support Program?
Reimbursement consideration instructions will be provided in the owner’s letter.
What if I have additional questions or concerns?
If you have additional questions or concerns, please contact the Toyota Customer Experience Center at 1-888-270-9371 Monday through Friday, 7:00 am to 7:00 pm, Saturday 7:00 am to 4:30 pm Central Time.