C1391

might need a new actuator. how many miles on her?

 

OP's profile looks like a Gen 3, where the actuator and accumulator are separate parts. They'd be the same assembly on a Gen 2.

Still, though it says "accumulator leak", the description I'm looking at suggests it could turn out, on further investigation, to be either part. I'd want to do my best to pin down which one, as they're both expensive, but especially the Gen 3 actuator, which is combined in one assembly with the master cylinder and ECU and is crazy expensive.

The basic gist of the code is: fluid ain't staying where the accumulator pump puts it.

From there on, it's gumshoe work. Is it staying inside the brake system? (Look carefully around all the components and lines for fluid escaping.) If inside, watch the reservoir level; after the car's been off for a good while (or you've deliberately "zeroed down"), the level should be at one level, but then if you trigger the pump to run, that level should get sucked down by around a cm or so. Does it then kind of sneak back up after the pump stops, without any use of the brakes? Could there be a bad seal, one of the actuator 'release' valves not fully closing, problem with the relief valve in the accumulator, etc? Some might be difficult to tease apart (all these things are sort of buried), but studying the diagrams in the New Car Features manual ought to give some ideas about the possibilities.

It's possibly helpful that the actuator/master cylinder assembly does contain at least five separate pressure sensors built right in (one for each wheel line and one for accumulator pressure), and Techstream lets you read them all, as well as control any of the valves individually to see what happens. Might be possible to learn something that way.

-Chap

 

I have the same problem, after shutting the car off the brake fluid is flowing to the max line again. when driving i hear a noise when my foot is on the brake. abs/traction/brake lights are on. i notice after hitting a pot hole they went on. mechanic code is 1391 any suggestions

 

well done!