I have a 2001 neon SE, the trac off light and ABS light is on, the ABS leads look clean and no broken wires. The speedometer works, so I am not sure if the speed sensors on the tranny are malfunctioning or not. How do I reset the computer to remove lights? If the input or output speed sensor were out would the speedo still work?

 

As for the ABS light...is your brake fluid low? That'll cause the light to come on...and is indicative that you either: need new brake pads or one of your brake lines is leaking.

 

The first thing I did was check the fluid, and I do not have a leak anywhere. I do remember so time back hitting a pot hole and then the light came on, but nothing is visually broke. i do not recall the last time i changes my pads, but they also look like they have a lot of life left. It will cost 100 bucks to get a full ABS diagnostic, is that normal? Sounds steep to me.

 

HVAC and ABS are two things that I really don't know too much about. Unfortunately, if it's not one of those two items, I'm not too sure where to go from here. Perhaps there is a problem with one of the control units? You can download the shop manual from my signature, and it'll show you everything in the system. Might help you find some other things to look at?

Best of luck!

 

Thank you, I will look at the manuel and go form there.

 

If you do not have a scanner to retrieve DTCs from the ABS module there are a few things you can do..

The most commonly failed component on the ABS system is the wheel speed sensors, that's where I would start.

Disconnect the sensors and using a ohmmeter, measure the resistance of the sensor. I don't know the specs off the top of my head but that should be something you can find in the shop manual.

If you can't find the specs then compare the 2 fronts against each other and 2 backs against each other. Also general rule of thumb is if it's in the Megaohms it's no good.

Other than that there really isn't much you can do without a scantool.

 

I put it on the scanner, it told me the car's ABS unit is unable to communicate with the scanner? The guy at O'Reilly said he has never seen this before. So I went to a shop and told them what is happening and they seem to think it is the ABS module that might be out. How do I test that? They also said unhook the battery and leave it sit 3 or 4 hours for the module to completely power down and it might reset itself.

 

I let it sit all day 7 plus hours, that did not work!! So I have no idea what to do other than take it in. I researched testing the leads but they work by magnets, so putting it on the meter wont help plus i tried i get the same reading on all sensors. Thank you all for the help.

 

If you cannot communicate with the module there are a NUMBER of things you should test before condemning it.

#1 make sure any ABS fuses the car has are fine.
#2 Check for power to the module (there may be more than one power, I do not have a diagram in front of me.)
#3 Check for ground to the module (again there may be more than one.)
There may also be a communications wire between the ABS module and other modules that would be important to check.

Also on a side note, you are correct that the WSS sensors work off of magnetism but that is because your sensor is a tightly wound coil of wire that uses what is called an exciter or tone ring to generate it's own signal based off of speed. The coil of wire is actually what you measure when you ohm it out.

 

Thank you, I got my hands on a scan tool with a manuel and was abel to take my time. I found out that the scan tool cannot connect with the car at all. The tool says unable to link with the car. As I stated above, first I thought it was just the ABS it was not connecting with but turns out I cant even connect with the car at all. What causes this problem? All fuses were removed and inspected and all fine. So to recap, I have the ABS and TRAC light stuck on, all fuses are good, and the scan tool will not communicate with the car.