Abs Light And Attesa Woes

[pomnz]

Hello to all I have decided to make a new thread about this problem as I am pretty desperate and even considering going to the local stealership for help so any ideas would be greatly received. Car is a 2002 VQ25DET NM35 with Hicas.

I changed my rear pads and rotors about 300kms ago and my fronts about 1500kms ago without issue and had been enjoying the improved braking feel until yesterday when I went round a bend giving it some decent throttle. The rear lost traction and stepped out a lot more than it should with the ATESSA and I had to apply a fair bit of opposite lock to straighten up. Once I'd stopped the ABS light popped on.

I tried restarting the car several times but after about ten seconds there is a soft whirring noise and then the ABS light comes back on and stays on. I've done the fault code thing and the ECU says no faults.

I'm sure the 4WD is not working as I went sideways again accidentally this morning when pulling out of a junction in the wet and almost crashed, not cool. I have also put it in snow mode and the torque needle gauge stays at 0.

I have looked at the car today and found that the brake fluid was over full, I presume this happened when I fitted the new brakes as I had to push the pistons on the calipers in to make room for the fresh pads. I drained the excess today but the ABS light is still on. Could this have damaged something? I guess it has been like this for approx 350kms?

The noise, which only lasts for a few seconds, comes from the part to the left of the brake fluid reservoir (ABS unit? See pic) and occurs approx 5-10 seconds after you switch the ignition on whether the engine is running or not, as soon as this part stops whirring the ABS light comes on and stays on.

So far I have tried unplugging the large plug next to this part and running the engine for a bit, there was no whirring noise but the ABS light was on immediately and stayed on. I have looked for the ABS sensors by removing a wheel as suggested but don't know what they are or where I should be looking, any help would be greatly appreciated.

I have attached a pic of the whirring part.

Thanks

[PN-Mad]

The ABS self checks at start up. It also has its own computer to control its functions. Thats when it figures out something is not right and puts the light on.

Sounds by all your near crashes like your in RWD.

two things come to mind- One- check your Attesa fluid- its in the drivers side REAR boot cubby hole. You have to take the plastic thingo out to access it.

Second. If one doesn't work, take the car to a mechanic with a scan tool, or Nissan dealership, and get them to read the error message. It might be as simple as one wheels ABS sensor has kaput. Replace, and its done. The abs sensor is the part that reads the little ring of bumps the goes around on the back side of the hubs.

hmmm you have hicas and therefore LSD. I am envy.

[scotty nm35]

I'm thinking the Hicas may be having issues too, you should still have plenty of grip in rear drive.

I would suspect a rear wheel speed sensor problem, get the wheel off and find the wire that goes to the hub, slide the disk off and check its all intact and the wire isn't broken. Take the sensors out and clean them too if you can. Anything further will need OBD2 diagnosis.

[czeno]

When pushing brake pistons back it would be better to loosen the bleed nipple at the caliper rather than force it back through the system.

[pomnz]

Attesa fluid is fine just above the max line, not had time to check anything else but thanks for the suggestions do far guys. Scott I also think speed sensors is the issue but we'll see.

[scotty nm35]

I just realized they are on the rear diff, not the hub. I have some spare ones here too if a cleanup doesn't work.

[pomnz]

Ok so turns out the code is 'U1000 can com circuit' which I got from my local garage as PN Mad suggested in the brakes thread.

I have read through the service bulletin http://engine-codes.com/uploads/nissan/NTB06-009a.pdf that refers to the ECM, I take it this is the ECU?

Has anyone fixed this themselves?

[zei20l]

yup seems to be the ECU

cleaning the grounds? sounds reasonable!

but this TSB isnt for an M35, its worth trying anyway.

i have spare sensors for the diff, and spare ECU if you need them. im sure there are others floating around too

[PN-Mad]

Pm replied.

Just clean the ground, make sure they all attached, even around the engine bay, and behind the dash. I've never had a light come on for it. And doesn't seem to effect anything.

Lol Iain, yeah it's not for m35, but heaps of other cars. I'd have to say it'd be effected.

Edited March 27, 2012 by PN-Mad

[pomnz]

Well many weeks and dollars have passed and I've still not sorted this issue. I've cleaned the grounds behind the dash as suggested, let me tell you that was not a fun job.

I took the car to Nissan who told me they had no idea what was wrong with it "coz its Japanese" and then they charged me for the privilege. The only useful bit of info I got out of them is that the code is definitely U1000 which according to them is "just a ghost code that doesn't mean anything". I guess that's why Alex sees it with no issues on his car. They also said that the abs control unit is not detecting any of the four wheel sensors which makes me think its not a speed sensor issue as the chances of all four failing at once is pretty remote.

Next thing I'm going to try is replacing the ABS actuator which I guess I may have damaged by forcing calipers open when i did the rotors ?

That's unless anyone has any better ideas?

I'm open to suggestions here guys so fire away.

[scotty nm35]

I have no idea where the abs computer resides but I would try swapping that first. I doubt the actuator is the problem. Have you checked all the fuses in all three fuse boxes? Perhaps there is a faulty relay in the power control unit behind the battery? I would be getting an auto elec to check it out if you get stumped. Where are you located?

[Daleo]

Well many weeks and dollars have passed and I've still not sorted this issue. I've cleaned the grounds behind the dash as suggested, let me tell you that was not a fun job.

I took the car to Nissan who told me they had no idea what was wrong with it "coz its Japanese" and then they charged me for the privilege. The only useful bit of info I got out of them is that the code is definitely U1000 which according to them is "just a ghost code that doesn't mean anything". I guess that's why Alex sees it with no issues on his car. They also said that the abs control unit is not detecting any of the four wheel sensors which makes me think its not a speed sensor issue as the chances of all four failing at once is pretty remote.

Next thing I'm going to try is replacing the ABS actuator which I guess I may have damaged by forcing calipers open when i did the rotors ?

That's unless anyone has any better ideas?

I'm open to suggestions here guys so fire away.

Pushing the caliper pistons back is part of the pad replacement process, and shouldn't affect the actuator.

When brake pressure is applied, it operates at over 500psi; pushing back the pistons won't do anything untoward.

[PN-Mad]

So did they read any codes off the ABS ecu, or just the engine ECU? They are two separate things.

Quick reminder of the symptoms? car is in rwd only and doesn't operate in awd, and has ABS error light, right?

If you were in sydney, I'd just say bring it round and i'll check for codes for you, but its not that easy I guess.

[pomnz]

Scott, I thought the abs control unit and the actuator were a combined unit?

I have checked the fuses in front of the battery and those in the drivers footwell, I didn't know there was a third box somewhere?

I'm located in Auckland.

Symptoms are that ABS light is on, ABS does not function, Attessa does not function so car is RWD only. Code is U1000 pulled from ABS unit not ECU. There are no other issues/symptoms or codes.

Code has been reset and appears again 15 seconds or so after you tun the ignition on so the problem is persistent.

I have removed all four speed sensors and cleaned them, they were not even dirty to be fair but thought I'd try it anyway, I couldn't seen anything wrong with the connecting cables or the teeth on the metal wheel thing that they scan.

I have cleaned the two ground connectors behind the dash and the battery connectors suggested in the TSB http://engine-codes.com/uploads/nissan/NTB06-009a.pdf

I have read http://www.jdmgallery.com/wp-content/uploads/2010/09/BRC.pdf

page 66 where it says that U1000 is either a break in the communication line itself or the ABS actuator and control unit which is what is making me think to change that part out.

[PN-Mad]

This is the anti skid control unit- at least from what I can find on the parts pages. Looks like its under the centre armrest/tranny tunnel sort of area.http://www.tygarbyte.com/images/stagea/info/M35%204WD%20light/47930AL800a.PNG

[PN-Mad]

Sorry, can't edit, but that seems to be the G sensor and is under the blanket of Anti skid control. Maybe see if you can swap one over with a working car. Its a pain that its not throwing any codes.

[pomnz]

Do you have the Jap service manuals? Where can I get a copy?

[PN-Mad]

Sorry mate, I don't.  I just use "epc data", and a few other things. search on google for it.

I think Scott might have something?

I use the FSM for G35s in teh states as it relates better for my car. Can be seen on NICO I think.

[bangahh]

Just updated the Tygarbyte site with a little bit more info, the 4WD light starting to annoy me......... always wishing the 4WD light wont turn on when i drive it on the weekends - it happens 90% of the time now.

My jaw dropped when I found out that a new 47930 AL800 part cost over $1000 new. This is also known as a YAW sensor, also read somewhere on a GTR forum that if you pull this out you may need to re calibrate it, but dont know why you would need to.

The Infinity G35 part is similar but looks different but part number slightly different 47930 AL700 - I havnt actually pulled the part in question out so I cant confirm what M35 part looks like. 2nd hand G35 YAW sensor goes for about $100 -$120 on ebay.

Bosch YAW info - pinout

www.tygarbyte.com/images/stagea/info/M35%204WD%20light/sensors_yawrate.pdf

so if anyone knows if M35 YAW "47930 AL800" is interchangeable with G35 YAW "47930 AL700" ???? ight take a punt to fix 4WD light.

[scotty nm35]

Is ours the same part as the r34 gtr? There are a few aftermarket ones available for GTR's now, perhaps one of them would be a cheaper and better option?