E46 ABS Issue.

[Arata 30]

Hi team, just wondering if I could have some advice...

I have E46 PFL 320i Sedan Year 2000 M54 5hp19 ZF Automatic with ASC ABS.

Recently the traction control light, abs light, handbrake light started to come up on dashboard.

Scanned the code and showed Rear wheel speed sensor/speed sensor signal interference/CAN fault DME.

Rear wheel speed sensor has been replaced no more than a year ago as already had the codes on. (but no lights on dashboard at that time)

I have rechecked that the wiring to the sensor and the sensor itself for any damage.

Checked the data stream for signal from the sensor and it is getting signal.

I have taken out the sensor once again, cleaned inside, checked for any damage inside the sensor hole.

The 3 lights on the dashboard, sometimes it comes on and stays on until I turned the car off and turned back on, then it all disappears without clearing the codes.

Sometimes it takes 1 week to bring the lights back on, sometimes within a day, or 3 days.

My question is, is it finally the time I rebuild/replace the abs module? The fact that the lights keeps disappearing and appearing (not at constant pace), is it getting some different signal interference from something else that's affecting the abs to play up?

Thank you very much for advance.

Arata.

[Gaz 1061]

Swap the rear speed sensors over and if the fault follows you've got a dud sensor again, but it does sound module related 

[Eagle 1662]

+1 swapping the sensor. If its an aftermarket sensor i wouldn't trust it - OE Conti\VDO is all id ever use.

[Arata 30]

Thanks Gaz and Eagle, have swapped the sensor, scanned again and nothing. Went for test drive and turned the car off. Still nothing showing.

Then when I turned into ignition, the lights came back on. I am leaning towards the abs module.

Any idea who does the rebuild in Christchurch?

[Vass 831]

There's a few other culprits that can set those 3 lights off as well. Is your steering wheel pointing perfectly straight when cruising in a straight line? Mine was offset by just a fraction and those lights kept on popping up intermittently until I got the steering linkage alignment just right.

Are you using just a generic scanner? I've got a few specialist softwares set up on my laptop, happy to do a scan for you, might help pinpoint the issue more accurately.

[Arata 30]

Hey Vass, thank you very much for input!

I have several scanners at home, but I recently installed Inpa/NSC Expert and have been great using them, though I have BMWs in the last 7 years I know I'm late catching up installing them haha.

As for the steering, just had a wheel alignment done when I replaced the tyres about 3 weeks ago, and the wheel alignment tech did say left front control arm is slightly bent for some reason, does not sway to the side anyway, but the steering wheel isn't perfectly straight.

The reason I'm leaning towards the abs pump/module at this stage is that very very occasionally there is a buzzing noise when I let go the foot brake. Does not happen often enough, but after the drive when it happens, turn the car back on and the lights seems to come up. When I pump up the foot brake it goes super hard like it should when the car is off, and regardless of abs lights on it still brakes really good so I'm sure the brake booster/master cylinder is fine.

[Vass 831]

Not sure on the buzzing noise but I'd take care of the steering wheel alignment first, then see if the issue persists. You need to have the steering wheel perfectly straight, then recalibrate the steering angle sensor with INPA/PA Soft, then drive it for a while.

I'm only saying that because I had exactly the same lights pop up just recently and the steering wheel misalignment was the cause of the issue. Only happened because I had the steering rack out of the car during an engine swap but in your case it sounds like there might be something bent or misaligned. 

Sure enough you might be right on the ABS pump being bad but even if you fix that and the steering wheel is still off center then you'll still have those lights popping up. 

[Dogballs 115]

Just note: ASC doesn't have a steering angle sensor. - only in DSC cars.

[Vass 831]

6 minutes ago, Dogballs said:

Just note: ASC doesn't have a steering angle sensor. - only in DSC cars.

Ahh my bad, disregard my ramblings. Didn't realise it was that different.

Cheers 

[Arata 30]

Hey guys. Wee update for my E46.

Had it running for couple of weeks without really doing anything to it, and has been off for a while but from last week the lights started to show up again.

 

Also, even when the ignition is on (without starting the engine) the lights comes up on dash and stays on, and of course, the 50% of other times disappears as they should like normally.

I've been busy with other E46 projects and currently in the process of getting E30 (LHD) 325i  2 door sedan M-tech 2 version so I apologise for not coming back here.

ASC doesn't have the steering angle sensor??? Thanks for the info I guess I can count that out for the issue I have.

As for this morning and throughout the entire day, no lights on dash. Nothing.

I'm starting to think it is actually the abs module even though codes doesn't really say anything apart from rear right wheel speed sensor signal interference...

Although the other things I mentioned earlier in this post, very occationally, the brake pedal has bit of buzz when I let go.

Note that the front/rear brake discs/pads are less than a year old and don't look bad, no visible leaks from the hoses (I do want to replace them all at some stage).

Wondering if the seals inside the master cylinder is getting worn out but that's not really massive concern for me...

Will keep you guys updated. Thanks.

[Dogballs 115]

have a read: E46 ASC info

might help you nut out the issue.. reading your first post fault code descriptor maybe its a CAN fault? 

that site provides diagrams for you to check wiring etc..

[Arata 30]

Thanks guys. I’ll read the info and will get on to it!

 

For last entire week, the lights decided not to show at all.

Today lights showed up again and I tried to scan with INPA and INPA doesn't communicate on ABS module and gets me back to the first page when you load INPA.

Is this mean ABS module is toasted?

I'll see if the lights decide to go out because if they go then I can scan it for some reason...

Or is it something else?

Edited April 18, 2023 by Arata

[Arata 30]

Update…

I’ve spent the entire day checking all fuses/wirings in the morning yesterday, seems all working fine, the fact that when I replaced the abs sensor at rear right around last year, and I rechecked the connection/wiring around it, as well as reluctor ring at the hub and it’s not broken, gave it a good clean, still didn’t change anything.

 

so I decided to replace the abs pump as I had a second hand one that’s already repaired before, sucked the brake fluid out from the reservoir, removed and replaced the abs pump, filled with new fluid, scanned and recoded using INPA/NCS Expert, carried out the brake flush through pressure bleeder. At this stage brake pedal feels firm as it should be.

When I turn the car to ignition, the lights were changed to amber yellow, hand brake light was on but when I started the car it turned off as soon as I released the hand brake, got out to the road and both abs light/traction control light went off and so far never came back on. Most likely I will bleed the brakes one more time in case, but otherwise brakes fine, abs works, I think I can say I’ve sorted out the issue.

 

The things I’ve learnt from this was never take in of what the scanner says, sometimes it would pinpoint out the problem doesn’t mean it’s the main cause of issues.

I’ll drive for next couple of weeks and if the lights doesn’t come back on I’m happy with it......

 

Edited May 26, 2023 by Arata

[Arata 30]

Hey guys, here comes the lights back at me again in the last few weeks,

This time it's so intermittent that the lights come back a lot more frequently than before.

So I went back all the way from the beginning of what I have done, researched the faults through, read the codes again, done erasing/clearing all faults etc.

The only faults come back on INPA is CAN Data fault from DME, Wheel speed signal interference. Pretty much the same as before.

So I have jacked the rear end of the car up, took the rear right wheel off, took off the abs sensor, just had a peek on the abs ring, nothing unsual except bit of dirt over the last couple of years built up so I degreased/brake clean the stuff out completely, refitted the abs sensor back on. Turned the car on and the lights were still intermittent.

 

Then, for bit of curiosity on my end, took out the rear right abs sensor again and fitted the old original bmw sensor back in (it was covered in dirt so I gave it a clean). Turned the car on and before plugging INPA on the lights disappeared. Put INPA through and no faults present. WTF.........

 

Then I realised, the abs sensor I have replaced for the rear right previously is from FCP Euro but it is Delphi one. I did search a lot and most people out there having similar issues with replacing aftermarket ones. I thought Delphi one is OE/OEM standard one but since it only lasted about a year, the fact that the old original one is surprisingly still working, I am quite disappointed the replacement one did not work at the end after all. The reason I replaced it in the first place was it was giving the fault codes on the scanner, however that time had no lights on the dash and everything was working fine.

 

I will see how my car behaves again, but I will replace with new original BMW sensor this time for sure.

At least the fight is over I think.