Rednroll

Introduction:
In this write-up I'm going to show the least expensive and best way to perform an ABS Brake Module Bleed using the OBD J-Scan app.

Observed Problems where you may want to perform this task:
- You are experience a soft brake pedal.
- You've bled your brake lines multiple times, and are certain you are not able to get anymore air out of your brake lines but your brake pedal still feels soft.
- You suspect your ABS module is bad, and would like to confirm that part is bad before making an expensive part replacement.
- You've replaced your ABS brake module and now need to bleed the module and would like to perform the bleed yourself instead of taking it to the dealership.
- Your brake fluid is old/dirty and you want to perform a COMPLETE brake fluid replacement flush

Tools/Parts Needed:
1. OBD-II Wireless Adapter (Wifi or Bluetooth)
I'm using a V-tech Wifi OBD-II adapter which I purchased in 2010. It was an inexpensive $20 adapter

2. A Smartphone or Tablet Device (to install the J-scan app)
3. OBD JScan App
Android: https://play.google.com/store/apps/d...hl=en_US&gl=US
iOS: https://apps.apple.com/us/app/obd-jscan/id1445903514
4. 11mm Wrench (Front Brake Bleeder Valves)
5. 10mm Wrench (Rear Brake Bleeder Valves)
6. Dot 3 Brake Fluid (1QT)
7. DIY Brake Bleeder Tool
- Empty Plastic Bottle with a cap (Clear preferred)
- 2ft of 1/4" ID Clear Tubing

- Drill a hole near the top of container just large enough to insert clear tubing
- Drill a small hole in the cap to let air escape during the brake bleed procedure
- Insert tubing so it reaches bottom of bottle
- Fill bottle with enough brake fluid so end of tube is submerged in fluid (ie can't suck up air back into the system)
8. An Assistant capable of holding down a brake pedal

Rednroll

1. Install OBD Jscan app on your smartphone device
2. Plug the OBD-II Wireless adapter into your JK's OBD Port (Located on driver's side below the dash)


3. Open up your Wifi Settings on smartphone and Connect phone to OBD-II Wireless Adapter
- Perform Phone Bluetooth pairing if you have a Bluetooth OBD-II adapter


4. Launch OBD JScan app
5. Select Vehicle JK Wrangler


6. Settings in App will appear,select the adapter to connect



Jscan will connect and scan the vehicle configuration


7. Setup is complete when this screen appears in Jscan with your vehicle's VIN information.

Rednroll

Pre ABS Module Bleed Setup
1. Connect your DIY Brake Bleeder tool to the Front Driver's side brake bleeder valve


2. Open your Brake Fluid Reservoir (remove fluid if doing a flush)
- If you are going to perform a complete brake fluid flush, then get a turkey baster or other suction pump and remove as much brake fluid from the reservoir as possible. You can also do a complete flush without doing the fluid removal, it just means you're going to use more brake fluid than needed and perform the bleed procedure more times.
Note: Do not spill any brake fluid on paint or electrical wires, it is highly corrosive. It is a good idea to put shop towels under your reservoir and drape some towels on nearby body painted areas to avoid damage due to accidental spills.


3. Fill your brake fluid reservoir with fresh brake fluid up past the max line without overfilling and set the reservoir cap to the side, making sure to avoid getting any dirt in the fluid or on the cap.


4. If you haven't done so already, it is advised to perform a manual brake line bleed before performing the ABS brake module bleed procedure which follows. I am not going to include those steps in this write-up but will add that manual brake line bleeds should be performed in the following order. (Furthest from Master Cylinder to Closest) PASSENGER SIDE REAR>DRIVER SIDE REAR>PASSENGER SIDE FRONT>DRIVER SIDE FRONT.

Rednroll

So now we're ready to perform the ABS Brake Module Bleed using OBD Jscan app.

Note: This is a 2 person job, where one person will need to hold the Brake pedal while the other opens the bleeder valves. It is likely not a good idea to attempt to wedge something in your JK to hold the brake pedal down for you. During this procedure, the ABS module will pump the brakes and when it does so, it will push the brake pedal upwards. The less air which is in the system, the harder that push force upwards will become where there may be a risk of damage to your interior if you tried to wedge something in there to hold the pedal down for you. My 9 year old son assisted me with this instead.

Perform ABS Brake Bleed:

1. In Jscan, select the "Adaptation" tab
2. Then select "Vehicle Maintenance" (You may have to scroll down to find it)


3. Select "ABS Brake Pump Bleed"


4. Warning Message, follow instructions and Press "Go"


5. Warning Message Press "Go" (completed in Pre Setup)


6. Warning Message Press "Go" (Completed in Pre Setup)

*Tip: If you see a communications error message after pressing "Go", then follow steps below in Communications Error section to fix.

7. Have your assistant press and hold down the Brake Pedal
*Tip: If your brake pedal is soft, it is best to have them quickly pump the brake pedal 3-5 times to build up some pressure in the brake lines so the pedal becomes firm and then hold the Brake pedal down


8. The ABS Brake Bleed Procedure will now start!
Tip1: The First part of the procedure Jscan will activate your ABS Module. Your assistant will feel your brake pedal pushing upwards against their foot, it will do this ABS Module pumping about 4 times about 1.5 seconds apart during each pump. Just have them continue to hold their foot firmly against the pedal during this pumping action.

Tip2: If you were concerned that your ABS module needed to be replaced, this is a great test sanity check. The ABS module is made up of 2 sections. One of the sections is the electronic control section(the black half) which operates 12 electrically operated piston switches inside of it. The second half is the mechanical half which has the DC motor pump and where the Pistons switches open/close into. If your assistant is feeling the pumping action against their foot, then this means the module is being electronically activated, and creating the pumping action(ie both sections are functioning). What we likely don't know at this point, is if all 12 of the pistons are moving as they should? However, if you are not feeling any pumping during this stage then this likely means you may need to replace your ABS module but lets continue with the bleed procedure to find out more.

9. Make your way over to the Driver side Front brake with your 11mm wrench and get prepared to open the bleeder valve to let air out of the system.
When JScan finishes the operation in step #8 above, the following screen will be displayed.
Tip: DO NOT OPEN THE BLEEDER VALVE AS THE INSTRUCTIONS STATE AT THIS POINT! This is very important, I learned from experience. You will get very little air out of the system following these instructions exactly.

10. Press the "Go" button above and then Jscan will display the following Screen
Tip: There isn't any test in progress when this screen is displayed. However it is time to get your 11mm wrench on that bleeder valve and get prepared to crack it open. When you press the "Go" button, JScan will immediately kick off the ABS pump to start pumping air out of the module.


11. With your 11mm wrench on the bleeder valve press the "Go" button above.
12. JScan will now activate the ABS module, followed by 4 consecutive ABS pumps which are 1.6 seconds apart.
13. Let Jscan perform the 1st pump with the bleeder valve closed.
Tip: With the bleeder valve closed during the 1st pump, this will pressurize the brake system and push any air in the system closer to the caliper bleeder valve.
After the 1st pump, Jscan will display the following screen which is a countdown before it moves onto the 2nd ABS pump action.

14. With your 11mm wrench on the bleeder valve, wait for Jscan to start the 2nd cycle ABS module pump action.
Once the 2nd pump begins, then crack the bleeder valve open 1/2 of a turn, to let the air combined with brake fluid out of the system.
15. Leave the bleeder valve open as Jscan continues with the consecutive pump actions, observing through the clear tube of your Brake Bleeder tool if air bubbles are exiting mixed with brake fluid.
16. Once Jscan completes the 4th ABS pumping action, immediately close the bleeder valve when the screen below appears.
Tip: As described previously the ABS module has 12 piston switches. There are 3 piston switches for each wheel. If you observed fluid being pushed out during steps 14&15, then congratulations! You just confirmed those 3 piston valves are functioning properly in your ABS module! If you didn't observe fluid being pushed out then sorry, you may have just confirmed your ABS module needs to be replaced.

17. Press the "Go" button above. Grab your Brake Bleeder tool , along with your 10mm Wrench and move to the Driver side REAR wheel. Also instruct your assistance to continue holding down the brake pedal.

18. Connect your Brake Bleeder tool to the Driver Side Rear bleeder valve.


19. At this point Jscan will be displaying the following screen.
Tip: Again VERY IMPORTANT! Do NOT open the bleeder valve at this step.


20. Press the "Go" button above and then Jscan will display the following Screen
Tip: There isn't any test in progress when this screen is displayed. However it is time to get your 10mm wrench on that rear bleeder valve and get prepared to crack it open. When you press the "Go" button, JScan will immediately kick off the ABS pump to start pumping air out of the module.


21. With your 10mm wrench on the bleeder valve press the "Go" button above.
22. JScan will now activate the ABS module, followed by 4 consecutive ABS pumps which are 1.6 seconds apart.
23. Let Jscan perform "2" consecutive pumps with the bleeder valve closed.
Tip: With the bleeder valve closed during the 2 consecutive pumps, this will pressurize the brake system and push any air in the system closer to the rear caliper bleeder valve.
After the 2nd pump, Jscan will display the following screen which is a countdown before it moves onto the 3rd rear ABS pump action.


24. With your 10mm wrench on the bleeder valve, wait for Jscan to start the 3rd cycle ABS module pump action.
Once the 3rd pump begins, then crack the bleeder valve open 1/2 of a turn, to let the air combined with brake fluid out of the system.
25. Leave the bleeder valve open as Jscan continues with the consecutive pump actions, observing through the clear tube of your Brake Bleeder tool if air bubbles are exiting mixed with brake fluid.
26. Once Jscan completes the ABS pumping action, immediately close the bleeder valve when the screen below appears.
Tip: As described previously the ABS module has 12 piston switches. There are 3 piston switches for each wheel. If you observed fluid being pushed out rear bleeder during steps 24&25, then congratulations! You just confirmed those 3 piston valves are functioning properly in your ABS module! If you didn't observe fluid being pushed out then sorry, you may have just confirmed your ABS module needs to be replaced.


27. Press "Go" button above and you will see the following screen.


28. CONGRATULATIONS! BUT YOU'RE NOT DONE YET! WE NEED TO DO THIS AGAIN ON THE PASSENGER SIDE!
However, you can tell your assistant that they can now let their foot off the brake pedal and give their leg a break.

29. At this point, go top off your Brake Fluid reservoir with more fresh brake fluid so the level is just above the max line.
Tip: You do NOT want to let the fluid run too low in the reservoir, otherwise it will draw air into the brake system and you will have to start over.

Rednroll

(Continued)
30. Goto Step #3 and perform the exact same steps on the Passenger's side.
31. Continue to perform the ABS Module Bleed procedure starting on the driver's side and ALWAYS finishing on the passenger's side until you observe absolutely no air bubbles coming through your bleeder tool's clear tubing.
32. Once you reached the point of observing no air and only fluid coming out during the bleeding procedure from ALL calipers, take your JK for a drive.
33. I would recommend to do the ABS bleed procedure on both sides one more time following your drive.
34. After all this, hopefully you're now enjoying a solid brake pedal and learned you didn't have to replace your ABS brake module.
35. Congratulations! Now you are done!



Communications ERROR FIX
If you receive a communications or other error during the ABS Module bleed procedure such as the message below then follow these steps to fix. The ABS Module is currently in a non communications state and needs to be rebooted.

Example communications Error Message


1. Press the ok button, then select the Restart all ECUs in the Jscan app


2. In the Target Value drop down, select "All modules - Power On Restart", then press the "Go" button


3. This procedure will take 2-3 minutes, you will see various lights on your dash turn on and off as each module is restarted. Do not interrupt this process!


4. Once all ECUs have been restarted, you will see the follow message. Press "ok"


5. Once complete, go back to Step #2 in Perfom ABS Brake Bleed Proceedure write-up section and continue.

Rednroll

Background Story:
Originally my driver's front caliper was sticking which followed a diagnostic code being logged of "C2200–ANTI-LOCK BRAKE MODULE INTERNAL". I original thought my ABS Module needed to be replaced based on that trouble code. It turned out instead that my Driver's Front rubber brake hose was collapse internally and needed to be replaced. While I was replacing that brake hose, my Driver's side hard brake line split open and that now needed to be replaced as well.

I had to wait for a week for this replacement hard brake line to arrive at the dealership. This line connects from the ABS module to the Driver's side front brake hose.
Mopar P/N: 52129117AD


During that week long wait, most of my brake fluid drained from the split brake line where my fluid reservoir was empty by the time the part arrived. I was expecting I would have to perform a manual brake line bleed but assumed an ABS module bleed would not be necessary since it was always said that the ABS module is closed off from the rest of the system when not activated. The brake line arrived, I replaced it and put everything back together. I filled my brake fluid reservoir back up and performed 4 different manual brake line bleeds. No air was coming out while performing the last couple manual brake line bleeds. However, what I observed was that I would have to pump my brakes 4 times before the pedal became firm. Which meant there was air still in the system but where? I can only assume at this point that my ABS module must had also drained of fluid and now was filled with air and needed to be bled as well.

Originally I followed the OBD Jscan instructions and performed the ABS Module bleed to the T, followed by a manual brake line bleed as they recommend. The thought behind performing the brake line bleed made sense because the brake lines are after the ABS module and if the ABS module was pumping out air during the bleed, then it only made logical sense that some of that air was going into the brake lines which followed. Also OBD Jscan states that ONLY the passenger's side needs to be performed for the ABS module bleed. What I noticed by following the instructions was that I would get a little bit of air out during the bleed. I ended up performing the ABS module bleed 20 times followed by a manual bleed. What I was noticing was that absolutely no air was coming out during those manual bleeds. Over the course of performing those ABS module bleeds my brake pedal did get better. It gradually went from needing 4 pumps of my brake pedal before the pedal became firm to 3/4 of a pump before I felt it firm and being fully firm after doing an immediate 2nd brake pedal pump.

After that much effort and seeing very little air come out in subsequent ABS module bleeds, I decided I would change up the Jscan instructions slightly. My prior experience when performing a 2 person manual brake line bleed was to have the person inside the vehicle to rapidly pump the brakes until the pedal became firm, thus the system being pressurized and then hold the pedal and at that exact moment, to crack the bleeder valve open. That always tended to get more trapped air out of the system. So that's what I decided to do for the ABS Module bleed as well. Before opening the bleeder valves, I would let JScan pump the ABS module with the bleeder valve closed, thus building up the pressure and then on later pumps, I would crack open the bleeder valve during one of the later pumps. OMG! did that work! I went from getting 1 or 2 bubbles of air coming out of the system when following the instructions to observing the entire clear tube flowing with air bubbles out of it. I additionally decided to do the ABS bleed on the driver's side as well, and that also showed the same benefits of more air flowing out of the system. I will say I got more air out of the system performing my modified stepped method 2 times than the prior 20 ABS bleeds following the instructions and during the 2nd modified instructions bleed I observed only fluid flowing. I then took my JK for a test drive and my brake pedal was now as hard as a rock like it is suppose to be. I came back and did my modified method one more time and observed only a few air bubbles come out. It was finally done! I will also say, when doing my modified method following the ABS bleed with a manual brake line bleed was no longer needed.

So that's my backstory and experience which I wanted to share with everyone in case anyone was wondering the reasons behind me modifying the steps in the Jscan ABS Module bleed process. It's because my modified steps as provided above work much better to force the air out of the entire brake system!

ABS Module Reference Information:

The black electrical control side (This side has your VIN programmed into it). J-Scan can also program VINs if you need to replace just this side.


The silver mechanical piston valve and pump side. (This side has the brake fluid in it, or trapped air).


There are a total of 12 piston valve switches which get opened/closed by the electrical side. There are 3 switches per each wheel which get activated and control the rapid brake pumping for each wheel when ABS is activated. The silver side is where all your brake lines connect. There are a total of 6 hard brake lines connected to the silver side. 2 are inlets which get fed directly from your master cylinder and 4 are an outlet which gets connected to each wheel's brake caliper so each wheel can be controlled individually.

resharp001

It's worth me asking again. Is your caliper upside down (installed on wrong side) in that picture?

Rednroll

I originally was having troubles with the driver's side front caliper sticking. So to eliminate the caliper as the problem, I swapped the front calipers to see if the sticking followed the caliper but it didn't and I don't think I swapped them back after that trouble shooting step. Is there a benefit to having the valves in the higher position? Probably easier to get air out of them when bleeding since air always rises huh?

I probably need to swap them back but at this point, I'm exhausted from bleeding my brake lines and am just thankful I currently finally have a nice and firm brake pedal again after spending 3-4 months trouble shooting.

Uhggg! Thanks for noticing and pointing that out, I'm going to put that on the tudo list to go back and swap them back to the proper sides.

resharp001

Yup, this exactly right here. Bleeder valve always goes to the higher position. I've seen this overlooked by others chasing brake issues as well and unfortunately it is a mistake that is easy to make and the only difference is that dang bleeder position when you do. (I see the ABS bleed fixed you're peddle, just noting the issues many have bleeding).

Rednroll

Yep, I just put all my tools away but I'm going to go back and swap those calipers while this is all fresh in my mind. As soon as you asked, it dawned on me I forgot to reverse my trouble shooting step of swapping the front calipers. I'm a pro on bleeding the system at this point, so should be back to having a firm pedal after the swap in no time. But who knows, maybe I'll find it will get even better when I get done?