"Engine System Service Required" - Brake vacuum leak?

[tony209]

Had this intermittent message for a while with no apparent problem with the engine. My brakes have been a bit spongy of late and had an issue were after heavy braking there was a temporary loss of brake pressure. This happened again at the weekend and I noticed the "Engine System Service Required" message. Would the engine management system detect a leaky brake vacuum as un-metered air and trigger this message?

[cheshired5]

Originally Posted by tony209

Would the engine management system detect a leaky brake vacuum as un-metered air and trigger this message?

I don't think so but even if it did, you need a code read done because it could be lots of things triggering the message and guessing is expensive.
You need to address your brake problem regardless of any codes.

[tony209]

Originally Posted by cheshired5

I don't think so but even if it did, you need a code read done because it could be lots of things triggering the message and guessing is expensive.
You need to address your brake problem regardless of any codes.

Thanks for the reply, just a thought. Booking the car in to get the brakes looked at. I thought the issue was a one-off but it happened again over the weekend but this time brake pressure came back after a few minutes rather than hours. The car has just passed an MOT, I thought they would fail it on the brakes and tell me what the problem was!

[bournricha]

Sounds very much as if air is in the brake system .Heavy braking will cause heat, which will expand the air and make the brakes spongey .After cooling the air bubbles will reduce in size and almost normal braking will continue .
Do or have done a really thorough bleed of the system ,if possible with a pressure bleed kit
This MAY be all that is needed .
The most dangerous sign would be if you found you were actually losing fluid .If you are, urgent attention is required
As Cheshire says engine light is probably unconnected and needs diagnosis as it can be for many reasons ,even a faulty wheel speed sensor can cause it to come on ,as well as all the air ,fuel parameters

[tony209]

Originally Posted by bournricha

Sounds very much as if air is in the brake system .Heavy braking will cause heat, which will expand the air and make the brakes spongey .After cooling the air bubbles will reduce in size and almost normal braking will continue .
Do or have done a really thorough bleed of the system ,if possible with a pressure bleed kit
This MAY be all that is needed .
The most dangerous sign would be if you found you were actually losing fluid .If you are, urgent attention is required
As Cheshire says engine light is probably unconnected and needs diagnosis as it can be for many reasons ,even a faulty wheel speed sensor can cause it to come on ,as well as all the air ,fuel parameters

No loss of fluid or signs of a leak. I'm going to bleed the brakes this weekend, if I can get some help! The feeling I got on the brake pedal when the issue occurred this time, was a slight loss of pressure followed by what i would describe as if the wheels were sliding on gravel - it's not the same feedback you get when the ABS activates

[bournricha]

If you get a pressure kit you wont need any help ,thats the beauty .They only cost £10-15 .What you have is a container of fluid pressurized by the reduced air pressure in a spare wheel .Then all you have to do is release fluid from each caliper starting at the back .It helps if you have a bit of clear plastic tube attached to each nipple in turn so you can see any bubbles that come out .Glad to hear no fluid loss.

[bournricha]

Was going to ask you about the ABS sensation but you have answered the question .That would be what thy call "false modulation ",but it would have that ABS feeling and would also put on the ABS light if it was false .It is narrowing down to air .Good luck with nipples if they have not been opened for awhile .
Don't how good you are with welding but i have sometimes welded a nut around the nipple to get a good grip

[cheshired5]

Originally Posted by tony209

No loss of fluid or signs of a leak. I'm going to bleed the brakes this weekend, if I can get some help!

A Sealey VS820 is all the help you'll ever need and powerful enough to flush your system and clutch with ease, dare I say enjoyably.
The best £40 you can spend.

[tony209]

Changed the brake fluid today, pedal is still spongy and also, I forgot to mention before, when you press the pedal there is the sound of either leaking or sucking of air from the pedal area.

3 brake nipples loosened and tightened fine, rear right nipple was a pig, managed to loosen it with a socket and wrench but when I tightened it again, it sheered off as easy as if it was made of toffee! Got that to sort out now!

Good news is that changing the fluid has sorted out mu heavy clutch pedal problem.