ESP/ABS/SAM Unit Problems

[trigger]

This is a bit of a long one, so please stick with me! The car in question is my 04 roadie cabriolet.

It all started about 6 weeks ago, when the ESP warning triangle lit up as I was driving along normally. Turning off the ignition seemed to clear the problem, and at first it only occured intermittently, coming on every few days or so.

This continued for a number of weeks, despite me fiddling with fuses and generally keeping my fingers crossed it would just go away!! It didn't!!

Fast forward 4 weeks to the day before my MOT. It had been sunny for the last month pretty much, but this day it was absolutely hammering it down. As I was driving along the car went mental!! Cut out, roof opened, dashboard lit up, lights flashed etc.

The car got completely soaked as I couldn't close the roof, and I had to get the AA out to get me restarted. Thankfully by the time they arrived the weather had cleared up a bit. The guy diagnosed water in the electrics, and managed to remove enough from the top of the SAM unit to get me going again.

The next day I managed to dry the car out as bes I could, gave the SAM unit a good once over with a hair dryer, and somehow it managed to pass it's MOT!! Personally I think it's because the seats were so went the tester didn't want to sit in it!!

Following the MOT I looked into the leak which caused the mental behaviour, followed the advice online and sealed up the wiper tray with mastic type sealent to prevent anymore water ingress. At the same time I gave the SAM unit another going over with the hair dryer.

For a day or two everything was ok, so naturally I linked the original ESP light fault to the water ingress problem. However, a day or so later the original problem returned, but this time it was accompanied by the ABS light. This hadn't happened before the mental behaviour. As it wasn't affecting the driving of the car, I persisted with it for a week or so till I had some time off to investigate properly.

Anyway, yesterday I removed the Sam unit from the car, took off the lid and removed the PCBs to have a look. As far as I could see, the only problem was a bit of corrosion around a single connector pin. The connector pin in question was N11-5, which according to Evil's guide is the one for windscreen wipers and lights etc. Which explains the breakdown and odd behaviour.

However, other than the small bit of corrosion the PCB seemed 100% intact. There was no dampness or moisture at all. I cleaned up the connector hoping it might solve the problems. It didn't

Driving to work today the same ESP and ABS lights came on. Although the ABS light seems to go off after a few secs, the ESP stays lit up like a xmas tree!!

The fact that the corroded connector N11-5 is nothing to do with ESP or ABS, and the fact that other than the corrosion which I removed the SAM was in good condition, leads me to conclude that my problem is elsewhere.
I think the water ingress was just an additional problem which threw me off the scent!!

So ESP and ABS lights, any thoughts? A few people have mentioned brake sensors. Is there any way to diagnose this? Steering sensors have also been mentioned. My steering wheel was replaced a year ago because the angle sensor was broken on the old one. The replacement was second hand, but was in very good condition, and has worked perfectly up till now?

Any thoughts or comments would be gratefully accepted!!

[10:45PM]

Re: ESP/ABS/SAM Unit Problems

steering wheels do fail on their own, so it could well be a duff steering wheel, don't discount it cos you recently fitted one.
also steering angle might need resetting/adjustment on the diag kit.

also to check is the brake pedal switch and/or adjustment of same.

If you're local to an indy, maybe get it on a diag kit to see if it's logging the fault and can point you more in the direction

[mocelet]

Re: ESP/ABS/SAM Unit Problems

I think it was ESP and ABS lights that I got when the brake fluid was low in the reservoir, but I might be wrong. It is however and easy one to check and rectify.

[137699]

Re: ESP/ABS/SAM Unit Problems

Most likely your ESP & ABS light is completely unconnected to the SAM problem. It's a common problem and is usually related to a faulty brake pedal switch.

I think it's purely co-incidence it happened a few weeks before your SAM problems.

[137699]

Re: ESP/ABS/SAM Unit Problems

As it wasn't affecting the driving of the car, I persisted with it for a week or so till I had some time off to investigate properly.

It doesn't affect the driving of the car, but it DOES mean the ABS & ESP functions are inoperative. So if driving with these lights on PLEASE TAKE CARE - especially on corners, roundabouts, and leave yourself plenty of braking room - especially in the wet - the lack of weight in the roadster makes aquaplaning & front and rear swapping ends quite a real risk when those systems aren't working!

[trigger]

Re: ESP/ABS/SAM Unit Problems

Cheers for all the advice guys.

However, having just driven the car I realise I made a mistake earlier. It's not actually the ABS light which comes on, it's the hand brake warning light!!

Does this put a new spin on things????

[madDan]

Re: ESP/ABS/SAM Unit Problems

from the handbook

Brake system indicator light
It lights up:
with the ignition switched on.
> The light goes out after the engine
starts or
> goes out after no more than 10
seconds.
with handbrake applied.
when brake circuit fails or brake fluid

level is too low.

Brake system indicator light
It lights up:
when the abs system malfunctions,

together with abs indicator light.

esp indicator light
It flashes:
when esp is working.
Light stays on permanently:
when esp is not responding.
in the event of system failure.
> It may be possible to clear a system

malfunction by restarting the car.

abs indicator light
It lights up:
with the ignition switched on (self
diagnosis).
> The light goes out after engine is
started or
> goes out after no more than
10 seconds.

if there is a fault in the abs system


Unfortunately not the ESP and Brake circuit lamp together


Maybe you have two faults?


I would check your brake fluid level as that is simple and would remove the brake circuit lamp if that was the cause for that.


But in hindsight maybe the symptoms are changing day by day? which would lead you back to the SAM suspicion.

What state is the connection to ESP ?

[trigger]

Re: ESP/ABS/SAM Unit Problems

I checked the brake fluid earlier, and it is perfectly normal.

When I took the SAM Unit apart, it was in perfect condition, except the one connector I mentioned, which has nothing to do with the handbrake or ESP.

Why are these things so damn complicated!!

[10:45PM]

Re: ESP/ABS/SAM Unit Problems

Check and/or replace the brake pedal switch if you can't get it diag checked , it's a cheap elimination.

There are two switches within the 'switch', one for brake lights (NO), the other signals to the car computer when you're pressing the pedal.(NC)

You can force the fault (on a fully working smart) you see if you ride the brake pedal when driving along (With accelerator too), the lights will come on after a short while cos it thinks there is a real problem with you apparently braking and accelerating

[trigger]

Re: ESP/ABS/SAM Unit Problems

Yeah, I guess it's a process of checking things one by one to eliminate them before shelling out hundreds/thousands of pounds on an unecessary fix!!

Thinking about the last few times it has happened, it has been in braking/accelerating situations, ie. traffic lights, roundabouts. So it would potentially make sense that the poor car is getting a little confused if I'm braking or accelerating.

I'll check the switch at somepoint today or tommorrow if I get the chance. If it is the switch, happy days. If not it's another thing off the list!!

[trigger]

Re: ESP/ABS/SAM Unit Problems

Right, I took out the brake switch today, tested it with my old man's multimeter, and everything appears to be working fine. So that's one thing off the list.

I've been racking my brains, and I have a couple of questions which might help me eliminate some other things.

My brake pads are fairly worn, and one of the offside pads has moved slightly in the caliper. However the brake fluid level is absolutely fine. I'm going to replace the brake pads ASAP, but is it possible worn pads could cause a brake system fault, light up the handbrake light and the warning triange? Surely if they were excessively worn, the fluid level would be a lot lower would it not?

Is it possible that a fault with the handbrake switch could be the cause? Obviously a fault would light up the handbrake light, but would it also light up the warning triangle?

Finally, is there anything in the steering wheel that would trigger the handbrake light? I think the ABS is linked to the steering wheel, but the ABS light is not coming on.

Cheers again guys.

[10:45PM]

Re: ESP/ABS/SAM Unit Problems

handbrake

Check it and eliminate it >> http://www.fq101.co.uk/roadsterhbrake.asp

They are all candidates I think, steering wheel, steering angle adjustment, handbrake switch... so get rid of the cheap fixes first.

checked the brake switch today, tested it with my old man's multimeter,

both switches within the switch ?

[madDan]

Re: ESP/ABS/SAM Unit Problems

Re the warn pads the fluid level would be a lot lower if it was the issue, the switch in the reservoir could be faulty.

The handbrake switch shouldn't cause ABS/ESP warnings, the Handbrake itself could possibly if it actually was stuck on.

You could also have a reluctor ring failure or sensor failure to bring the ABS lamp on.

Have you visually checked that the handbrake/ shoes in the drum isn't stuck on inside the drum? are the rear wheels free to rotate with the handbrake off? maybe it is chocked up and not releasing them?


I'll also ask again, have you checked the state of the connections on the ESP / ABS module?

It's not uncommon for the ESP unit to fail.

[trigger]

Re: ESP/ABS/SAM Unit Problems

Time for the daily update!! Sorry if people are getting bored of this thread now!! It's just so annoying when something goes wrong and you can't put your finger on it!!

Firstly, Mad Dan, I actually made a screw up in the title of this thread, it's not the ABS light which is coming on, it's the one below it. The brake system light/handbrake light. Not sure if that rules anything out or in?

I know I have probably said some contradictory things, such as confusing the ABS and handbrake light. So thought I'd clear it up by running through the symptoms as they currently stand.

The car starts fine, and runs perfectly to begin with. Then at a random interval (sometimes 5 mins, sometimes 10 or 15) the handbrake warning light comes on with the ESP warning triangle. After a few secs the handbrake light goes out, but the ESP warning triangle stays lit up. Sometimes when I continue driving with the ESP warning triangle lit up the handbrake light comes on and goes off again. To me this indicates the fault is recurring, and not constant. When I switch the ignition of the lights all go out, and the process starts over so to speak.

There doesen't seem to be any definite pattern in when the fault is occuring, although I have noticed it on the same stretch of road a few times, possibly suggesting that similar patterns of braking/steering are setting it off?

I've eliminated the brake switch by testing with a multimeter. Both switches worked fine.

My brake pads are worn, and new ones are in the post (although I'm sure the strikes will delay their arrival!!) The brake fluid level is normal despite the warn pads, so I don't think this is causing it.

As I mentioned before, the ABS light is not coming on, so I assume this rules out reluctor rings, or anything ABS related?

The handbrake itself could probably do with a little tightening, but the light comes on and goes out as normal when the car is stopped, and I'm not getting any beeping which normally indicates the handbrake is on when driving. I'm yet to test the handbrake switch as it involves taking the seats out etc, but if necessary I will.

The steering wheel is still a potential candidate, as it was replaced about a year ago. I'm not sure of the exact inner workings, but I'm not sure anything connected to the steering wheel itself would set off the handbrake light?

Finally the SAM unit. I had problems with water a couple of weeks back, but thought I had solved the problem. The leak is sealed, and the SAM is bone dry. When I inspected it there was only one small area of corrosion around a single connector which has nothing to do with the brakes. I suppose it is possible that there is invisible damage to the SAM causing a short circuit?

So in conlusion, I am mightily confused!!

[nigelengland]

Was there ever a solution to this issue?
My Brabus Roadster is now doing the same thing!
Many thanks
Nige.