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00 1500 Abs Bleed


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#1 cwendel4

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Posted 14 April 2010 - 06:39 AM

Does anybody know of the best way to fully bleed the brakes on a 2000 GMC Sierra 1500 with ABS. My old fluid had turned goey in the master and I did a vacuum bleed on the system. ANy way to activate the ABS without the dealer?

Also, any body know of a all the grounds that will cause a C0265 to be thrown for the ABS. I know the code because I have the AutoEnginuity Scan tool and have read that code when both lights turn on.

Help!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
I don't care what it costs to fix as long as it is done right the first time.

#2 MaForrest

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Posted 14 April 2010 - 08:19 AM

Does anybody know of the best way to fully bleed the brakes on a 2000 GMC Sierra 1500 with ABS. My old fluid had turned goey in the master and I did a vacuum bleed on the system. ANy way to activate the ABS without the dealer?

Also, any body know of a all the grounds that will cause a C0265 to be thrown for the ABS. I know the code because I have the AutoEnginuity Scan tool and have read that code when both lights turn on.

Help!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!



Well Im not too sure but Im going to take a stab at it. Your ABS isn't a mechanic system really. They are sensors that tell your truck when your wheel(s) lock up so it will release preasure to allow wheel to regain traction again. If you want to turn it off while bleeding your brakes, then just take out the fuse in the panel or you can unplug them from each wheel. The front ones will be right next to the brake line. You can miss it. Just follow the wire coming out of your unit bearing and you will see the plug. As for the code, you might have a bad or unplugged sensor for one of your tires. That could be causing your ABS code and light to come on. Like i said, i aint no mechanic but I have a little knowledge and hope if helps.
1997 GMC Sierra x-cab/SB 4x4, 5.7/4L60-E, dana 44 front and 9.25 rear, 3:92's, coiled and radius arm suspention, 35" KM2's on 15x10 DC-2 black.
1972 Cj5, AMC 304, NP435, Dana 300 T/S, toyota 8" front and rear with 4:56's and lock rights, stretched 8" and sprung over on rear toyota leafs on all corners.

#3 rmck490

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Posted 14 April 2010 - 09:12 AM

To bleed the brakes and ABS properly you will need a scan tool with bidirectional controls such as a Tech2. I'm not sure if a Snap On will do it or not. If you don't have access to one, you will need to take it to a technician.

Automated Bleed Procedure:

Important:

Use the two-person bleed procedure under the following conditions:
Installing a new Electro-Hydraulic Control Unit (EHCU) or new Brake Pressure Modulator Valve (BPMV) .
Air is trapped in the valve body
Do not drive the vehicle until the brake pedal feels firm.
Do not reuse brake fluid that is used during bleeding.
Use the vacuum, the pressure and the gravity bleeding procedures only for base brake bleeding.

Two Person Procedure

1. Raise the vehicle in order to access the system bleed screws.
2. Bleed the system at the right rear wheel first.
3. Install a clear hose on the bleed screw.
4. Immerse the opposite end of the hose into a container partially filled with clean DOT 3 brake fluid.
5. Open the bleed screw 1/2 to one full turn.
6. Slowly depress the brake pedal. While the pedal is depressed to its full extent, tighten the bleed screw.
7. Release the brake pedal and wait 10 - 15 seconds for the master cylinder pistons to return to the home position.
8. Repeat the previous steps for the remaining wheels. The brake fluid which is resent at each bleed screw, should be clean and free of air.
9. This procedure may use more than a pint of fluid per wheel. Check the master cylinder fluid level every four to six strokes of the brake pedal in order to avoid running the system dry.
10. Press the brake pedal firmly and run the Scan Tool Automated Bleed procedure (all except diesels above 15,000 GVW) once, or run the Function Test (diesels above 15,000 GVW) four times. Release the brake pedal between each test.
11. Bleed all four wheels again using Steps 3 - 9. This will remove the remaining air from the brake system.
12. Evaluate the feel of the brake pedal before attempting to drive the vehicle.

Bleed the system as many times as necessary in order to obtain the appropriate feel of the pedal.

Here is a TSB about the ground:
TECHNICAL

Bulletin No.: 04-05-25-002E

Date: March 11, 2009

Subject:
ABS Light On, DTCs C0265, C0201, U1041 Set and/or Loss of Communication with Brake Module (Reground EBCM Ground)

Models

Supercede:

This bulletin is being revised to add step 2 to the procedure and update the Parts and Warranty Information. Please discard Corporate Bulletin Number 04-05-25-002D (Section 05 - Brakes).

Condition

Some customers may comment that the ABS light is on. Upon further inspection, DTCs C0265 and C0201 may be set in the brake module. It is also possible for DTC U1041 to set in other modules. There may also be a loss of communication with the brake module.

Cause

A poor connection at the EBCM ground is causing unnecessary replacement of brake modules.

Important:
The EBCM ground is different for each application. Refer to the list below for the proper ground reference:


^Midsize Utilities = Ground 304

^SSR = Ground 400

^Fullsize Trucks and Utilities = Ground 110

Correction

Important:
Do not replace the brake module to correct this condition. Perform the following repair before further diagnosis of the EBCM.


Perform the following steps to improve the connection of the EBCM Ground:

1. Remove the EBCM Ground. The EBCM Ground is located on the frame beneath the driver's side door. If multiple grounds are found in this location, the EBCM ground can be identified as the heavy (12-gauge) wire.

2. If the original fastener has a welded on nut, remove the nut from the frame, and if required, enlarge the bolt hole to accommodate the new bolt and nut.

3. Clean the area, front and back, using a tool such as a *3M™ Scotch-Brite Roloc disc or equivalent.

4. Install the ground, then the washer and then the bolt to the frame.

Important:
It is important to use the bolts, washers and nuts specified in this bulletin. These parts have been identified due to their conductive finish.


5. Install a washer and nut to the back side of the frame.

Tighten

Tighten the nut to 9 Nm (79 lb in).

6. Cover the front and back side of the repair area using Rubberized Undercoating.

An additional check can be made to ensure a good connection for the battery cable to frame ground. It is possible for this ground to cause similar symptoms with the ABS as described above.

I had this problem but I simply cleaned the grounding point and sealed it from the elements. The problem hasn't returned since.

Hope this helps.

Attached File  EBCM_Ground.gif   26.57KB   33 downloads


#4 truss64130

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Posted 14 April 2010 - 09:22 AM

Do you still have to activate the ABS module if you just replace fluid? I thought that just as long as you don't get air in the system, then a flush should be fine... At least I hope so. I bought a pressure bleeder (like a pump garden / bug sprayer) that pressure bleeds the old fluid out and pushes new fluid in, all without letting air in the the Master Cylinder. My ABS still works and I never received any brake messages / lights.

If I am wrong, I sure would like to ensure that the ABS is bled properly

#5 rmck490

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Posted 14 April 2010 - 10:05 AM

Do you still have to activate the ABS module if you just replace fluid? I thought that just as long as you don't get air in the system, then a flush should be fine... At least I hope so. I bought a pressure bleeder (like a pump garden / bug sprayer) that pressure bleeds the old fluid out and pushes new fluid in, all without letting air in the the Master Cylinder. My ABS still works and I never received any brake messages / lights.

If I am wrong, I sure would like to ensure that the ABS is bled properly



I don't know the correct answer to that question. Somebody with more knowledge than I will have to give you an answer. The automated bleed procedure I posted does appear to only apply if you replace the EBCM or have air in the valve body. If it were me, I would do it anyway as a matter of insurance.

#6 cwendel4

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Posted 14 April 2010 - 08:11 PM

Thank you for the post and the correct procedure to bleed the brakes using the ECBM. I am going to check the latest version of the software and see what I now have access to. I know I need to bleed the accumulator in the system to get rid of the last of the bad fluid. I know I will need at least 2 quarts of fluid, it took two to bleed the system manually at the wheels.

Also thank you for the diagram of the location of the ground strap. I cleaned this one in the past after the codes had started. I am going to clean all of the grounds and add some more between the body, chassis and engine to help the electrical systems.

And yes and no to the need to bleed. If you remove a component, you will need to bleed the system. When the fluid has become contaminated, the entire system should be flushed and bled to remove the problem.
I don't care what it costs to fix as long as it is done right the first time.




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