I have a nice service manual and wouldnt you know, there is no Brake section! I must have missed that section when I printed everything off (use a PDF file). I have the ABS light on and went to program my tire size with the Superchips programmer and because the ABS light is on I can not calibrate my tire size. So, now I need to troubleshoot the ABS light. Does anyone have any advice or suggestions?
I am not sure where to begin? It is my guess I have a bad sensor or something so I think I need to unplug each sensor and put a volt meter on them to find the bad one? Sound right? Any other tips, suggestions or things I should try first? I dont have any history as the light was on when I bought the Jeep.
I've seen ABS sensors tested on other vehicles before by back probing the connector and spinning the wheel with the key on. The oscillations in current are so fast that you need a graphing meter though, which cost a lot more than that dealer diag fee.
I believe I saw a scanner in advance auto the other day that would pull ABS codes, I don't know how much it was though. I'd look at it this way: just paying to have it done will probably be cheaper than buying the necessary tools to diagnose....and easier too!
__________________ The Past
95 ZJ Laredo 4.0
00 WJ Laredo 4.0 & 4.7
08 WK Laredo 4.7 (traded for tin can) The Present
07 JK Unlimited Sahara
Well, I figured I would try again since I have some new information about my ABS issue.
We went wheeling and of course flexed out the rig pretty well and also used 4Lo quite a bit througout the day. Well, when we finished and I put the TC back into 4HI (all-time), my ABS light went off? WTF? I was stoked but about 1/4 mile down the road, I hit a good size bump and bam! Light came back on? I have since tried going in/out of 4HI/4Lo to replicate but have not been able to get the light to go off again. I am going to keep my Superchips programmer in the Jeep just in case it does it again so I can calibrate my speedo before it comes back on but I would like to find the bad connection and fix this once and for all...
So, this tells me that everything likely works but that I have a connection problem so now I am wondering where should I start? Are there any speed sensors in the TC that would have triggered it or do you think it was just all the flexing? The light didnt go off until I shifted back into 4HI so I am thinking there must be a sensor in the TC? Any ideas?
ABS is one of the topics people here dont seem to talk much about. I have posted few questions and have never seen a reply. I got a code 30 - ABS pump circuit bad or something like that.
These are the suggestions I found after a major search on the internet.
1. Clean the contacts.
2. Check the fuses.
3. Check power at the pump. I get 8.45 volts, not sure if that is correct.
4. Like someone said here, check the current sent by the sensors.
5. Clean the sensors and check the air gap between the rear sensor and the tone rings.
I did all the above and I just need confirmation on how much voltage the pump needs (volts at the pump connector). If it is 12v, then I know that the CAB is not giving out enuf voltage and I may end up replacing the CAB.
Hope this helps you in your search to fix the ABS.