Question about 2001 GMC Sierra 1500HD

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EHCU ABS IS it possible to remove the ecu with out taking the hcu loose from the lines?

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Yes under cab on frame with torx bit without removing lines
remove connectors 2 and remove torx bolts then remove ecu.
hope it helps
EHCU ABS - 7752cf9a-7de0-47df-99ee-2aff52c5a399.jpg

hope it helps note: EBCM not ECU

Posted on Mar 24, 2014


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Do I have a proportional valve?

no (and yes) the car has ABS.
if zero fluid there, then the ABS modulator is real bad.
or its input bad called the master cylinder.
the MC has 2 parts inside, one can fail and other ok.
to finds this is easy, learn to crack lines.
means loosen the flared fittings. or the bleeds where found.
my guess you mean that both rear bleeds are dead.
so move forward and crack (loosen the fittings so they can leak)
person to pressure brake, key off is ok, brakes work with no key on.(manual brakes if no blockages)
so if the lines are dead on ABS MOD but good in front
the ABD mod is toast (rusted inside)
when did the brake work right, list week .last year, or?
the modulator is called in jeep the HCU
see those fittings? ccw is loose.

the fsm is free, read it yet,?
WK is same car.

posted over 300 times this free fsm link.

i only have questions.
1: did you remove any parts.?
2: did you attempt to bleed the brakes and not read the words in the FSM on how to do that first>
3: or say car was parked for 1 year.
then you found brakes in rear bad. or have ABS or Brake failure lamps glowing??????
or the scan tools show errors?
then decided to check for fluid pressure on rear of car using , stand methods.,
4: were both rear caliper lacking pressure, or just 1 side.
the post implies both..."brakes". but>>>>?????

as you can see , us knowing the full story,
is a win/win... the context of your work.

Apr 14, 2016 | 2008 Jeep Commander

1 Answer

Where is the ECU on my Van with 4 wheel ABS system.

ecu is usually located under hood driver side fender

Oct 31, 2014 | Cars & Trucks

1 Answer

Brake system

I have no idea why people change a master

Take one apart some time & just clean out the
moisture & move on to bleeding all four corners
BEFORE any other work

Then replace rubber hoses,fabricate brake tubing &
replace rusted calipers etc

You need a helper in the car & motor running to bleed !!

Lets get your head into the game here
If it was the brake booster-- is that not common to all
four corners & the back is okey

Also you have the motor running, so you have already tested the

Could you have two bad flex hoses--- yes
Could you have two bad calipers ---yes
Could the HCU (hydraulic control unit-abs) be
all rusted inside & an issue--yes

Aug 28, 2013 | Chevrolet 1500 Cars & Trucks

1 Answer

Can I dsiable abs brakes 2002 4runner

You can remove the abs pump fuse & see what

The question is why?

You have conventional brakes until a wheel slips

I would command the hcu unit open & then remove the fuse

When you go to inspection, you fail, as the ecu/pcm/ecm, etc
won't be ready,it will be looking to run a test on abs every time
you start the engine or turn key on

Feb 14, 2013 | 2002 Toyota 4Runner

1 Answer

Where is the abs pump in a 2000 galant

Galant and Mirage

0900c152800383f6.jpg enlarge_icon.gifenlarge_tooltip.gif

Fig. HCU mounting-Mirage

0900c152800383f7.jpg enlarge_icon.gifenlarge_tooltip.gif

Fig. HCU mounting-Galant

  1. Use a syringe or similar device to remove as much fluid as possible from the reservoir. Some fluid will be spilled from lines during removal of the hydraulic unit; protect adjacent painted surfaces.

CAUTION Brake fluid contains polyglycol ethers and polyglycols. Avoid contact with the eyes and wash your hands thoroughly after handling brake fluid. If you do get brake fluid in your eyes, flush your eyes with clean, running water for 15 minutes. If eye irritation persists, or if you have taken brake fluid internally, IMMEDIATELY seek medical assistance.
  1. Remove the splash shield from the left front wheel house or fender area.
  2. Remove the coolant reserve tank.
  3. Remove the coolant reservoir bracket.
  4. Remove the dust shield from below the hydraulic unit.
  5. Disconnect the brake hoses and lines from the hydraulic unit. Correct reassembly is critical. Label or identify the lines before removal. Plug each line and each port immediately after removal.
  6. Remove the cover from the relay box. Disconnect the electrical harness to the hydraulic unit.
  7. Remove the bolts holding the 3 mounting brackets to the vehicle; remove the unit downward and out of the vehicle.

NOTE The hydraulic unit is heavy; use care when removing it. The unit must remain in the upright position at all times and be protected from impact and shock.
  1. Set the unit upright, supported by blocks on the workbench. The hydraulic unit must not be tilted or turned upside down. No component of the hydraulic unit should be loosened or disassembled.
  2. The brackets and relays may be removed if desired.

To install:
  1. Install the brackets and relays if they were removed. Tighten the bracket bolts to 16 ft. lbs. (22 Nm).
  2. Install the hydraulic unit into the vehicle, keeping it upright at all times.
  3. Install the retaining bolts holding the brackets to the vehicle. Tighten the bolts to 16 ft. lbs. (22 Nm).
  4. Connect the hydraulic unit wiring harness.
  5. Install the cover on the relay box.
  6. Connect each brake line loosely to the correct port and double check the placement. Tighten each line to 10 ft. lbs. (13 Nm).
  7. Fill the reservoir to the MAX line with brake fluid.
  8. Bleed the brake system.
  9. Install the dust shield and the coolant reserve tank with its bracket.
  10. Install the fender splash shield.
  11. Check ABS system function by turning the ignition ON and observing the dashboard warning lamp. Test drive the vehicle and confirm system operation

Jun 09, 2012 | 2000 Mitsubishi Galant

1 Answer

Need to know what HCU and ECU stand for

from where are u getting "hcu" & "ecu"

Apr 03, 2012 | 2003 Ford Escape

1 Answer

How do to replace the abs control module?

If you are talking about just replacing the electronic ABS module (EBCM), it simply unplugs and unscrews from the hydraulic control unit. If you are talking about replacing the hydraulic control unit (HCU) then you must disconnect the EBCM. Disconnect all of the brake lines from the HCU. Remove the mounting bolts from the HCU and remove HCU from vehicle. Then you reverse th order to reinstall. Once it is installed you must use a scan tool to perform automated bleeding to get all the air out of the hydraulic unit and the rest of the brake system.

Feb 21, 2011 | 2006 Chevrolet Trailblazer

1 Answer

I hve a 96 chevy 1500 4wd with brake issues. ABS light is on in the dash. Have replaced both frt calipers, pads, hoses. Replaced rear brakes and drums. Replaced master cylinder. Bled two quarts of...

you may have air trapped in the ABS EHCU. Did you use this procedure?

Bleeding the EHCU

Bleeding the EHCU requires the use of the TECH-1 scanner or its equivalent and the appropriate cartridge. Additionally, 3 tools, J-39177 or equivalent, are required. Bleeding cannot be performed without this equipment.
The EHCU must be bled after replacement or if air is trapped within the unit. It must be bled after bleeding the master cylinder and before bleeding the individual wheel circuits.
The Internal Bleed Valves on either side of the unit must be opened 1 / 4 - 1 / 2 turn before bleeding begins. These valves open internal passages within the unit. Actual bleeding is performed at the two bleeders on the front of the EHCU module. The bleeders must not be opened when the system is not pressurized. The ignition switch must be OFF or false trouble codes may be set.
  1. Open the internal bleed valve 1 / 4 - 1 / 2 turn each.
  2. Install one tool J-39177 on the left bleed stem of the EHCU. Install one tool on the right bleed stem and install the third tool on the combination valve.
  3. Inspect the fluid level in the master cylinder, filling if needed.
  4. Slowly depress the brake pedal and hold it down.
  5. Open the left bleeder on the front of the unit. Allow fluid to flow until no air is seen or until the brake pedal bottoms.
  6. Close the left bleeder, then slowly release the pedal. Wait 15 seconds.
  7. Repeat Steps 4, 5 and 6, including the 15 second wait, until no air is seen in the fluid.
  8. Tighten the left internal bleed valve to 5 ft. lbs. (7 Nm).
  9. Repeat Steps 3-7 at the right bleeder on the front of the unit.
  10. When bleeding of the right port is complete, tighten the right internal bleed valve to 5 ft. lbs. (7 Nm).
  11. Remove the 3 special tools.
  12. Check the master cylinder fluid level, refilling as necessary.
  13. Bleed the individual brake circuits at each wheel.
  14. Switch the ignition ON . Use the hand scanner to perform 3 function tests on the system.
  15. Carefully test drive the vehicle at moderate speeds; check for proper pedal feel and brake operation. If any problem is noted in feel or function, repeat the entire bleeding procedure.

Oct 10, 2010 | Chevrolet 1500 Cars & Trucks

1 Answer

ABS indicator remains on

remove the brake lines and HCU. unplug the modual and istall new modual. if ou havn't had the van checked out, i would, there are a number of things it could be that are alot cheaper than a new modual. could just be a wheel speed sensor.

May 19, 2009 | 2001 Ford Windstar

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