Chris8428

Hi All,

I have an intermittent ABS light on my 2001 Maxima SE. My question is in reading the factory service manual on page 91 of the Brake section it says to "ground pin 9 of the data link connector" and then count the number of flashes to determine the malfunctioning part. I am not understanding how to ground the pin to enter the code reading mode.

As a side note, the FSM says to start with a check of the brake fluid level, booster and pads to eliminate any of these being an issue. These items all appear to be operating normally and the brake fluid is within normal levels.

Chris

uptownsamcv

go to Autozone and have them scan it, usually the scanner they use will pull ABS codes..

first thing I would do is a complete brake fluid flush. I've seen ABS issues go away just by doing a thorough brake fluid flush. when I first got my Maxima I had times where I would loose pedal pressure and only my back brakes would work and after doing a thorough brake flush. it never happened again and that was years and around 150,000 miles ago. I'm guessing once the fluid gets old and builds up moisture the valves in the ABS module start to act up and stick. keep in mind that all the fluids a vehicle uses has lubricating properties to them even antifreeze for the water pump bearings. I drain and refill my radiator annually to prevent water pump failure. my original engine made it to 330,000 miles without water pump issues up until swapping the 2014 engine in.

from what I remember, every time you turn your key to the run position the ABS system cycles the valves in the module to test them. I've seen one instance on a coworkers Maxime that he would start the car and just have no pressure cause the valves were sticking after he started the engine. a friend of mine had an Armada wich had the same issue at only 75,000 miles and a complete brake fluid flush made the issue go away.

Chris8428

Thanks for the response. You are correct about the ABS check. The FSM says every time you start the car the ABS test is conducted and then the first time the car reaches 6 KPH the test is run again, if I remember correctly. A brake fluid flush is cheap and easy enough I can try it in the next few weeks and see if it solves the issue.

Child_uv_KoRn

iTrader: (7)

Usually just rusty bits stuck to sensor.

Chris8428

Afternoon All-- Just to update progress on this issue, my issue was a driver's side rear ABS wheel speed sensor. I tried getting the system to enter the self diagnostic mode as described in the Factory Service Manual, but I could never get that procedure to work. In the end a friend with a scanner that will show ABS codes checked it for me.

In reading other threads on this topic the issue can be solved by cleaning the sensor. I will see if the sensor has rust on debris on it and try and clean it. If that does not work, I will head to a salvage yard and pull a sensor. So this raises a second question and if this needs to be another thread I can start one, but are all fifth generation abs wheel speed sensors the same? I ask as on RockAuto there are different part numbers between 2001 and 2002, but on Autozone the part numbers are the same.

Chris

uptownsamcv

I would just get a new one on Rockauto. I installed 2 Ultra Power brand sensors on a friend's Toyota Venza earlier this year and it hasn't had any issues at all since last march. on that car it was making the vehicle dam near undriveable before changing it and the mechanic she usually goes to wanted around $600 to change them. she's an old friend and actually flew me into Georgia to fix it and hang out, I didn't even charge her.

you may also want to check the wheel bearing for play on that wheel with the bad sensor. but from my experience the rear wheel bearings on these cars were built to last. I'm at 43X,XXX miles and my rear wheel bearings haven't had any issues in the 11 years I have owned my car.

Chris8428

Afternoon All,

I just added "SOLVED" to the title of this thread. Child_uv_KoRn, was correct and the sensor was coated in a sticky film. I cleaned it with an electronic parts solvent I had on hand and it started working again. One thing to note when making this repair, and it is mentioned in the service manual, but the ABS light will not immediately turn off. You must use the manual reset method, which I could not get to work, or you must drive the car for a complete ABS test cycle for the light to reset. I had the battery disconnected for over a day and the light still immediately came on until the two ABS test cycles the computer runs were completed without a fault in the sensors.