Suspension, Steering and Brakes DTCs realting to brakes

Discussion in '4th Generation (2004-2012) [Acura RL]' started by Legendliving, Wednesday 13th Feb, 2013.

  1. Legendliving Club Member ★ ☆ ☆ ☆ ☆

    Does anyone know if it is possible to bring up DTCs relating to brakes so they are readable on the navigation screen? I have a recurring problem where the CMBS/ACC/LKAS is disabled if I press on the brake pedal heavily beyond a certain point. The main dealer wants to have it in for a couple of days to test it. If I can diagnose the problem myself it could save me some serious money.

    Thanks
     
  2. Ichiban Founder Staff Team

    England CJ Leeds
    30,129
    6,381
    516
    Could you explain more about this recurring situation, please

    What speed have you set cruise control at ?

    What distance gap have you set for ACC ?
     
    Loading...
  3. Legendliving Club Member ★ ☆ ☆ ☆ ☆

    Thanks for getting back so quickly. You did ask for details so here goes.....

    This is the second time I've had this problem, the first time it went away at about the time I had new discs and pads, but that may be co-incidental. At present and for the last 6 weeks or so, regardless of whether the ACC is set or even switched on, if I press my foot on the brake pedal hard, I get the orange warning lights for for ACC and CMBS and the large beeping warning message for ACC/CMBS/LKAS and these systems are disabled. If I turn off the ignition and set off again there is a CMBS warning message, but the ACC light is green and with ACC on as soon as a car comes within sight of the radar and causes me to slow, the CMBS light goes out and the car performs normally until and unless I have to brake hard. Minor braking, either manually or by CMBS does not affect it. Major braking by the CMBS alone has yet to trigger this problem, only manual braking.

    This is very irritating and I believe there is a simple answer and that the major radar equipment is fine, but I wonder whether a main dealer wiould see it that way? Any ideas really welcomed.

    My current theories are it might be the switch above the brake pedal, or a brake pressure sensor triggered by insufficient pressure in the master cylinder. The brakes aren't too spongy though.
     
  4. Ichiban Founder Staff Team

    England CJ Leeds
    30,129
    6,381
    516
    Hallo bud,

    All four tyres of the same make and speed rating ? The lessons were carried from Legend owners first sighting these bizarre concerns of random deactivation . http://hondakarma.com/threads/52/

    You haven't pushed the car with the engine turned off have you? I know the car is heavy and it will take a strong dude to push the Legend :Rolf:but it can cause the system to get into a loop http://hondakarma.com/threads/2162/

    I will investigate this issue further for you... but lets start with basic first. I wish you lived closer I would have scanned the ECU to see what DTC are being logged.

    If you can keep a record of what happens when at what speed it will help too.
     
    Last edited by a moderator: Sunday 23rd Feb, 2014
    Loading...
  5. Legendliving Club Member ★ ☆ ☆ ☆ ☆

    Thanks again for your interest. I have probably driven 3000 miles with this problem so I can tell you exactly how it happens. It has been triggered at speeds from 70 on the motorway, down to less than 5 mph while parking. It occurs when the brake pedal is depressed beyond a light braking pressure. It doesn't happen every time but in 90% of occasions it does. I have 4 michelins that have been on the car about 18 months. All the same speed rating and the car has never been pushed. Initially the problem was very intermittent, only occurring when braking after a long trip, but after a week or two it settled into this pattern. I also had the same problem for a few weeks about a year ago.
     
  6. Ichiban Founder Staff Team

    England CJ Leeds
    30,129
    6,381
    516
    Have you had a minor shunt at the front end windscreen change, I won't look into the brake being the source of the issue.

    If any of the above have occured then the system may need a calibration which is a RPA

    EDIT

    You cannot see or clear ADAS errors it has to be done via DLC according to Honda.
     
    Loading...
  7. Legendliving Club Member ★ ☆ ☆ ☆ ☆

    Thanks again. I have owned the car for nearly three years. I have it serviced at an independent Honda specialist that I have used for 20 years. Actually prior to my ownership the car had clearly been repaired following a frontal collision. I have had a windscreen change, but about two years ago. Neither of these coincided with the onset of this problem though.

    I have also remembered that I had a similar problem for a few days in spring 2011. From reading the Acurazine Forum, I concluded the most likely suspect was a poorly charging battery and as I was travelling a long way from home and quite freaked by all the warning lights at the time I gambled and opted to pay £60 for a new battery and it solved the problem. On reflection, would the battery change have cleared the ADAS errors regardless of having the new battery? My current battery is fine.

    As it all works perfectly apart from when I brake heavily, my gut feel is that all is generally well with the system. I have read reports of VSA warning lights being triggered by the brake/cruise switch on the brake pedal and there was also the TSB issue with the VSA module on V6 Hondas of this era leaking air into the master cylinder which would be picked up by the brake pressure sensor on the CMBS system.

    As I say, this fault is an irritation and takes away some of the joy of driving this car, but I don't want to spend a fortune on new parts unless they really are required. I am due a service shortly and I'll get the brakes looked at. If that doesn't cure it, given the cars history, I will save up and take it to a dealer with a view to getting it recalibrated as you suggest. Thanks again for all the ideas - it's fantastic to get this sort of help.