Ziggyrama

iTrader: (15)

Hey guys,

I am starting to see my ABS light come on occasionally. I have a base 03 Z which means no VDC and traction control involved here. The light comes and goes and doesn't seem to be related to anything specific. It does happen sometimes when I turn the ignition ON but I do not crank the starter to start the car. I can hear a buzzing sound coming from the front of the car. I usually turn the ignition ON and wait a couple of secs for the fuel pump to prime so I know the normal sounds that go on at that time. The buzzing sound I hear from the front, possible the engine bay, does not sound normal and it happens when I see the ABS light stay on so I am certain they're related. It sounds similar to a small, struggling electric motor.

I do not know much about the Nissan ABS system but I am pretty car tech savvy. If I knew the components of the ABS system, than I could probably figure out what is wrong but my knowledge is lacking on this right now. I do have extended warranty on my Z so I am trying to determine the problem first and then see if I can get it fixed under warranty. I do not want to go to a steelership and have them have at it without me knowing what the problem is. I don't have enough trust in these places to do that. So, some questions for you guys:

1. Does the ECU store codes from the ABS system? The light was on so if the ECU stores the related code, that can help me figure it out. The light is probably triggered by a component not responding to the ECU query within certain voltage range or resistance.

2. What could possibly be responsible for the sound? Is there an electric motor in the ABS system that could be on its way out and thus producing this noise?

3. Any other info I am missing? I could definitely use a brief overview of the ABS system and how it works. Again, I understand electronics so feel free to get as technical as you'd like.

Thanks in advance guys. Help is much appreciated.

DavesZ#3

iTrader: (26)

When the car has been sitting for a while, shortly after starting, the ABS goes through the self-test which does result in the pump making the buzzing noise you hear. You can also feel it through the pedal if you're applying the brakes. This normally happens about 15-30 seconds after starting.

I would assume if there is a problem, then yes, the light will come/stay on.

You have an 03 but didn't say if you've owned it since then or recently got it. The first thing I would check is brake fluid and pads. Low pads and fluid can result in some of the abs/brake/slip lights coming on.

I don't think the ECU will have a code to read unless the CEL light is on. From what I understand, the ABS system does have it's own tests/diagnostics but chances are the dealer will be the only one to have the tool that can access it.

Besides the ABS pump/controller, a defective wheel speed sensor can also trigger the ABS. Have you done any work on wheels, axles, brakes, suspension recently?

Q45tech

Explained fully in Factory service manual use Consult II or III to diagnose or step by step in manual without Consult.

Probably easier to pay dealer to diagnose then decide who replaces what.

Ziggyrama

iTrader: (15)

Thanks for the reply. Here's some more info:

1. I've owned the car for over 1 year now. No issues with brakes before other than just normal pad replacement, front and rear. I replaced the fronts about 6 months ago. I did the rears about 3 months ago. No indication of abnormal wear on the pads. No steering issues, vibration, etc.

2. I haven't done any work in the area other than just wheel swapping between winter/summer setups. I did that about 1.5 months ago. No suspension work has been done. Basically the car is stock other than wheels and normal maintenance items.

3. Checked the fluid level the other day. MC is at the correct, full level. Haven't noticed any change in brake pedal feel. Brakes work very well.

I have tried to do some research to get more info on the system, what the components are and how it works. I guess first step is to find out what system it is. I haven't found a definitive answer but it seems that Nissan has been using Bosch 5.3 brake system in various models like Altima, Frontier, Quest and Sentra. It's possible the Z also uses this system as it has sports car applications as well. Any ideas on that?

Ziggyrama

iTrader: (15)

Yes, a good scanner can actually do ABS system diagnostics and tests in order to isolate the problem. From what I have read, an intermittent ABS issue like a motor that is flaking out, will most likely not leave a stored code in the system. Getting a hold of a good scanner that can do ABS diags would be nice. I know AutoZone rents scanners but I doubt theirs can do the ABS checks.

As far as dealership thing, I will most likely take it there and have them do it anyways HOWEVER I do not just take my car blindly and trust them to only replace parts that need replacing. Dealerships have a pretty bad track record with that and when it comes to non-budget cars like the Z, they get even more eager to sell me parts I really don't need. I've caught them several times do this and luckily, I know enough to spot BS when I see it. I don't feel that I know enough now to take it in and have them do the work. Unfortunately, Nissan dealers here, and I have several to pick from in my area, do not inspire confidence. It's said but true. Ok, enough on that.

If anyone knows which system the Z uses, speak up. That will help me greatly in getting an idea on what is wrong here. And I can learn something new in the process. I found a good read here on ABS:

http://www.babcox.com/editorial/bf/bf20136.htm

Ziggyrama

iTrader: (15)

BTW, I meant no disrespect by my reply if it may have come across that way. I appreciate any help you can provide in this matter. I am just the type that likes to understand things instead of just blindly opening up the wallet and paying.

I stopped by AutoZone a little while ago and found Actron's ABS scan tool. It lists domestic car support, no imports. I wonder if it works with Nissan's ABS. I am considering buying it and trying it out. If it does not work or shows no useful info, I have 90 days to return. Here's the link to the scanner:

http://www.actron.com/product_detail.php?pid=16349

dnguyent

iTrader: (5)

Ziggy, any luck chasing down the problem?

I just posted this on another thread:

Last year, I had a unique problem in which my ABS module shorted. The ABS motor would run non-stop even after shutting down the engine and pulling the key out of the ignition. Luckily, I was able to chase down the problem, remove the module, and send it to a specialist for repair.

This problem I have now is different. The ABS motor is not running, and all the lights turn on immediately after twisting the key and they stay on. Normally, they would turn on, pass diagnostics, and turn off at the blink of the eye.

Ziggyrama

iTrader: (15)

I have not had a chance to chase this down yet. The light comes on occasionally especially after I heat soak the car. The ABS motor makes a buzzing noise when the ABS light stays on. I do have my extended warranty in effect so I may just drop it off at the dealer and have them scan the ABS system.

I did try the Actron scanner but it is geared towards domestics. I should have guessed that given it's sold at Autozon

If I have any more info, I'll update the thread. Sounds like your problem is different than mine since I have not had issues with the level of my brake fluid.

dnguyent

iTrader: (5)

Consider contacting this guy: http://www.modulemaster.com/en/index.php

I'm going to have the dealership perform a Consult II scan since the OBDII scanner from Autozone isn't picking up anything. If they don't know what it is or suggest to replace the ABS module, I'm sending the unit to modulemaster.

dnguyent

iTrader: (5)

As an update to this thread, I ended up sending my ABS module to ModuleMaster.com, and they repaired it. I reinstalled the unit tonight, and the lights went out! I went this route because my warranty is out.

I'll test the abs tomorrow by trying to lock up the tires under braking.