The first signs of this problem were of the brake actuator pump continuing to run intermittently after the engine was turned off. The brake actuator eventually got to leaking down enough to trip the above mentioned code. Through much research and heartache, I eventually come to understand that I had a faulty leaking brake actuator that should have been recalled by Toyota. As I am a retired field service engineer with decades of electrical and mechanical engineering experience, I would not recommend a novice or shade tree mechanic replace this actuator by themselves. It is extremely difficult and not to mention dangerous if one isn't experienced with ABS systems and hydraulics.
Long story condensed: I purchased a new brake actuator (PN: 44050-50170) from eBay and replaced the faulty brake actuator (PN: 44510-50070) myself which cured the problem.
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Brake Malfunction, Check ABS, Check VSC System.
Failure Code: C1391 Abnormal Leak of Acc Pressure
The first signs of this problem were of the brake actuator pump continuing to run intermittently after the engine was turned off. The brake actuator eventually got to leaking down enough to trip the above mentioned code. Through much research and heartache, I eventually come to understand that I had a faulty leaking brake actuator that should have been recalled by Toyota. As I am a retired field service engineer with decades of electrical and mechanical engineering experience, I would not recommend a novice or shade tree mechanic replace this actuator by themselves. It is extremely difficult and not to mention dangerous if one isn't experienced with ABS systems and hydraulics.
Long story condensed: I purchased a new brake actuator (PN: 44050-50170) from eBay and replaced the faulty brake actuator (PN: 44510-50070) myself which cured the problem.
Faulty Brake Actuator: 44510-50070
Good Brake Actuator: 44050-50170
- willeverett, Grant, AL, US