My 2020 Camry Hybrid LE has 36,400 miles on it and will be four years old in mid-February. I have owned several Prii across three generations, and the 12-volt batteries have lasted 8 or more years. The Camry 12-volt battery is only 4 years old, but today I was not able to start / boot the car. My first thought was that a rear brake job done a few days ago messed up the Camry electronics (more on the brake job below). The dash displayed the message “Toyota Pre-Collision System Malfunction”, after which it displayed “Parking Brake Unavailable”. I was not able to manually engage or disengage the parking brake, and the parking brake light blinked continually. Also, with the brake pedal depressed, I experienced a foot massage as if the ABS was working. The car was “confused” about being in accessory mode versus being turned on, the dash lights flickered and dimmed, and the power windows were sluggish. The headlights were plenty bright so I didn't think there was a 12-volt battery problem.
In early January I heard a rubbing sound coming from the right rear wheel. I use an independent mechanic for basic repairs such as brake pads and rotors. On Monday of this week, my mechanic found the outer right rear brake pad was down to less than 1 millimeter, though the other 3 rear pads were in the 3 to 4 mm range. The right rear rotor was scored. All 4 slides moved freely, so we couldn't explain the single worn pad. In my experience, hybrid rear brakes last over 150,000 miles, so the failure of a single pad was suspicious.
We put the car in “Electric Parking Brake Replacement Mode” as documented in the Toyota repair manual. The brake motors whined and fully retracted (the procedure is very finicky, and it required several tries). My mechanic disconnected the wiring harness from both motors and removed the motors. He then replaced the rotors and pads on both sides, lubed the slides, reinstalled the motors, and reconnected the harness to the motors. We then turned off "Electric Parking Brake Replacement Mode”. The foot brake and parking brake worked fine, and I heard the motors engage when the parking brake button was activated. I left the parking brake in manual mode due to the extreme cold weather we have been having in Massachusetts this week.
On my drive home from the independent shop, a red warning light for the pre-collision system came on. The car was covered in road salt, ice, and water from Monday’s snow storm. The light has come on before, usually with a message to “clean the sensor”. This time there was no message. The light went out at some point, and the pre-collision system worked properly, beeped, and displayed the word Brake when a car in front of me stopped short a day or so after the brake job. The parking brake worked fine all week, and I engaged and disengaged it manually due to the extreme cold weather.
Several days prior to the brake repair, I started the car, drove a very short distance, and both screens displayed the "boot up" images and messages that appear when you first power on the car. I found this very unusual, but it didn’t occur again. Now I wonder if this was indicative of other problems with the electronics.
I planned to have the local Toyota dealer run some diagnostics and service the car. AAA came to tow the Camry to the dealer, but the driver insisted on first trying to jump the car. He claimed to have seen similar warning and error messages on other hybrids that simply had a weak 12-volt battery. I was skeptical, but let him connect jumper cables to the special fuse box connector and the frame. Much to my surprise, the car booted / started right up. All the errors and warnings are gone. I re-enabled automatic mode for the parking brake, and that is also working fine.
This is a lot of background information, but I want to rule out the brake job as being the cause of the errors and warnings.
My short question is, could a weak 12-volt battery be responsible for the car not starting, the “Toyota Pre-Collision System Malfunction” error, and the other symptoms I described?
Thank you,
David Schwartz
Framingham, MA
In early January I heard a rubbing sound coming from the right rear wheel. I use an independent mechanic for basic repairs such as brake pads and rotors. On Monday of this week, my mechanic found the outer right rear brake pad was down to less than 1 millimeter, though the other 3 rear pads were in the 3 to 4 mm range. The right rear rotor was scored. All 4 slides moved freely, so we couldn't explain the single worn pad. In my experience, hybrid rear brakes last over 150,000 miles, so the failure of a single pad was suspicious.
We put the car in “Electric Parking Brake Replacement Mode” as documented in the Toyota repair manual. The brake motors whined and fully retracted (the procedure is very finicky, and it required several tries). My mechanic disconnected the wiring harness from both motors and removed the motors. He then replaced the rotors and pads on both sides, lubed the slides, reinstalled the motors, and reconnected the harness to the motors. We then turned off "Electric Parking Brake Replacement Mode”. The foot brake and parking brake worked fine, and I heard the motors engage when the parking brake button was activated. I left the parking brake in manual mode due to the extreme cold weather we have been having in Massachusetts this week.
On my drive home from the independent shop, a red warning light for the pre-collision system came on. The car was covered in road salt, ice, and water from Monday’s snow storm. The light has come on before, usually with a message to “clean the sensor”. This time there was no message. The light went out at some point, and the pre-collision system worked properly, beeped, and displayed the word Brake when a car in front of me stopped short a day or so after the brake job. The parking brake worked fine all week, and I engaged and disengaged it manually due to the extreme cold weather.
Several days prior to the brake repair, I started the car, drove a very short distance, and both screens displayed the "boot up" images and messages that appear when you first power on the car. I found this very unusual, but it didn’t occur again. Now I wonder if this was indicative of other problems with the electronics.
I planned to have the local Toyota dealer run some diagnostics and service the car. AAA came to tow the Camry to the dealer, but the driver insisted on first trying to jump the car. He claimed to have seen similar warning and error messages on other hybrids that simply had a weak 12-volt battery. I was skeptical, but let him connect jumper cables to the special fuse box connector and the frame. Much to my surprise, the car booted / started right up. All the errors and warnings are gone. I re-enabled automatic mode for the parking brake, and that is also working fine.
This is a lot of background information, but I want to rule out the brake job as being the cause of the errors and warnings.
My short question is, could a weak 12-volt battery be responsible for the car not starting, the “Toyota Pre-Collision System Malfunction” error, and the other symptoms I described?
Thank you,
David Schwartz
Framingham, MA
