Reference
C1391: brake accumulator pressure
Counted at
- Repair orders
- 20Fault code C1391
- Shop
- 1Atomic
- As of
- Read live from Shop-Ware
At each shop. One shop has this work in its own repair orders.
Atomic AutoPortland, OR20Model years 2008-2015- Replaced the brake system 15 times
- Repaired the brake system 5 times
C1391 is the brake system saying the accumulator is losing pressure or taking too long to charge.
Toyota hybrids keep a reservoir of high-pressure brake fluid in an accumulator so the brakes work instantly. C1391 sets when that pressure leaks down or the pump runs too long to restore it, and it often arrives with a pump that can be heard running after the car is parked.
What owners notice
A brake warning light, a pump that can be heard running after the car is parked, a pedal that feels different from day to day, grinding from rusted rotors, or a car that pulls when it stops.
What the shops check first
The hydraulic system's pressure behavior and stored codes, the condition of the friction hardware (slides, pins, rotors and pads), and the fluid. On hybrids and EVs the brake system has its own computer, and some service steps need a scan tool to put it in a safe mode.
What the repair usually involves
Anything from cleaning and lubricating seized hardware to replacing rotors and pads, up to an actuator or accumulator replacement on cars whose pressure system has failed. The shops follow the maker's procedure for bleeding and resetting the system afterward.
What the shops' records show
The count at the top of this report is every repair order matching this problem across the EV Partners shops, recounted from their Shop-Ware records whenever they sync. Below it, each shop that has done this work shows its own share, the model years it saw and what it did, with a link to its own write-up where one exists.
Questions owners ask
Is C1391 expensive to fix?
It depends on what the testing finds. Many cases end with a smaller part than owners fear. The shops test before they quote and explain the options and their trade-offs first.
Can I keep driving with C1391?
Sometimes, for a short while, but warning lights on a hybrid or EV are worth checking soon. Some faults reduce power or stop the car without much notice, and a few involve high voltage. Call one of the shops and describe what the car is doing.
Which shops in the network work on this?
The shops listed in the At each shop section have repair orders for this problem in their own records. Each one books its own work, so contact the one nearest you directly.
Cite this report
EV Partners (2026). C1391: brake accumulator pressure. EV Repair Hub. 20 repair orders from Atomic Auto, counted Oct 29, 2026.
We count the repairs. These shops do them.
EV Partners does not repair cars. Call a shop and tell them the code, C1391.
