C5 Tech Corvette Tech/Performance: LS1 Corvette Technical Info, Internal Engine, External Engine, Tech Topics, Basic Tech, Maintenance, How to Remove & Replace
Sponsored by:
Sponsored by:

ABS module question

Old 03-11-2012, 04:24 PM
  #21  
HTWHLS
Melting Slicks
 
HTWHLS's Avatar
 
Member Since: Mar 2001
Location: Suwanee, GA
Posts: 2,547
Likes: 0
Received 0 Likes on 0 Posts

Default

Originally Posted by HTWHLS
Thanks Bill, and everyone. I have checked and confirmed the codes (thanks for the repost of that process). I also have the estimate from the dealer with the numbers and I have the same code as noted C1214. I am going to see if I can get the part out today. I am also going to check the grounds while I am in there and replace the battery since this problem also seems to be draining the battery. I don't drive the car much since its actually for my wife and it spends a good portion of its time as "garage jewelry."

I appreciate all the help people. As you can see from schedule, I'm only getting back into this thread today..two weeks later. Will let everyone know how I make out.
First, again, my thanks for all the assistance and information.
If you have met me, you know while I'm handy, I'm also vertically-challenged so bending over the fender and my reach is going to be limited.

I pulled all my codes and except for some history codes addressed a long time ago, the only current code was the C1214.

It took me just about an hour to get this out, but I did it. 25 minutes of which was figuring out how I could get my chunky square paws in there and how to disconnect the white clip. (mover's blanket over the right side fender and drape over the engine with chest on the intake; pull in on plastic top and push toward radiator). I wisely pulled out my magnetic "fetcher" and after the bolts were loosened, used the magnet to pull them out so I didn't drop them. I have again, learned to appreciate the SAE technicians for their knowledge, skill and apparently. flexibility.

The order has been placed and this will go out tomorrow morning.

While I'm out there, I am checking all my grounds as well. Thanks for the tip on that.

Again, folks, I can't thank you all enough for the sharing of knowledge and support. I can't wait to get this thing back and see those lights on the dash go away.

If anyone has any tips as to how my meaty little fingers can get those screws started in those long recessed holes..do please share. I tried magnetizing my Torx driver ..but it didn't see to work. If anyone wants to do it for me..well, afterwards there is adult beverages available.

Much obliged!
Old 03-11-2012, 04:36 PM
  #22  
barrynk
Racer
 
barrynk's Avatar
 
Member Since: Aug 2005
Location: Raleigh NC
Posts: 277
Received 6 Likes on 4 Posts

Default

I just went through this for process for the second time. Kudos to Brandon, he repaired it originally in 2007 & again in Feb 2012 (at no charge); great service. C1214 is gone.

Reinstalling the unit the second time around was much easier. I put a small dot of Krazy glue on the underside of the bolt heads and glued them to the module. The glue holds each bolt in place on the module while you get it lined up. The torx driver can them easily break the minor glue bond when you start to drive them home. Just be sure to use just enough glue to hold the bolt in place, a tiny dot is all you need
Old 03-26-2012, 02:25 PM
  #23  
HTWHLS
Melting Slicks
 
HTWHLS's Avatar
 
Member Since: Mar 2001
Location: Suwanee, GA
Posts: 2,547
Likes: 0
Received 0 Likes on 0 Posts

Default

Originally Posted by HTWHLS
Thanks Bill, and everyone. I have checked and confirmed the codes (thanks for the repost of that process). I also have the estimate from the dealer with the numbers and I have the same code as noted C1214. I am going to see if I can get the part out today. I am also going to check the grounds while I am in there and replace the battery since this problem also seems to be draining the battery. I don't drive the car much since its actually for my wife and it spends a good portion of its time as "garage jewelry."

I appreciate all the help people. As you can see from schedule, I'm only getting back into this thread today..two weeks later. Will let everyone know how I make out.
Ok, for those of you bored enough to follow this thread, I got the part out and actually it wasn't bad. After I figured out a way to get my meaty little paw in there after removing the air bridge.

I sent it out to ABSFIXER and got it back last Wednesday (as they promised) and put it back in yesterday. (Shout out to Jessica at ABSFIXER: thanks for tracking my order and calling me back after business hours! Great voice!)

It slid right back into place with no issues. I got 4 of the six Torx screws back in (2 on top and 2 on bottom) but I just can't get those 2 middle ones, in the long deep slots, into place. I gave up after 90 minutes. I was going to try and glue them to my Torx driver but then on the last two attempts, I dropped the screws. I spent another 20 minutes trying to find them. They did NOT hit the floor. I have to figure something else out but in the meantime, does anyone know the thread pitch/length offhand or where I can get that spec so I can replace them, if I can't find the other two?

Oh..and if you're attempting this, watch the fins on the power steering cooler..they are razor sharp. I shaved a good bit of the hair off the back of my hand/arm..and a bunch of skin as well.

I'm going to try to find the screws tonight and if so, will enact my plan B of rubber-cementing them to my driver.

Appreciate all the advice, assistance and moral support. Last night it took a bunch of Dewars to get over that experience!

Last edited by HTWHLS; 03-26-2012 at 02:28 PM. Reason: misspelling and forgot to give kudos to Jessica
Old 03-26-2012, 02:31 PM
  #24  
HTWHLS
Melting Slicks
 
HTWHLS's Avatar
 
Member Since: Mar 2001
Location: Suwanee, GA
Posts: 2,547
Likes: 0
Received 0 Likes on 0 Posts

Default

Originally Posted by barrynk
I just went through this for process for the second time. Kudos to Brandon, he repaired it originally in 2007 & again in Feb 2012 (at no charge); great service. C1214 is gone.

Reinstalling the unit the second time around was much easier. I put a small dot of Krazy glue on the underside of the bolt heads and glued them to the module. The glue holds each bolt in place on the module while you get it lined up. The torx driver can them easily break the minor glue bond when you start to drive them home. Just be sure to use just enough glue to hold the bolt in place, a tiny dot is all you need
Thanks Barry. If I had seen that before I tried to install it, I would have tried it. That may have to be my plan C as it looks like I may have to take it out if I can't find those screws!
Old 04-05-2012, 06:57 PM
  #25  
HTWHLS
Melting Slicks
 
HTWHLS's Avatar
 
Member Since: Mar 2001
Location: Suwanee, GA
Posts: 2,547
Likes: 0
Received 0 Likes on 0 Posts

Default

Originally Posted by HTWHLS
Ok, for those of you bored enough to follow this thread, I got the part out and actually it wasn't bad. After I figured out a way to get my meaty little paw in there after removing the air bridge.

I sent it out to ABSFIXER and got it back last Wednesday (as they promised) and put it back in yesterday. (Shout out to Jessica at ABSFIXER: thanks for tracking my order and calling me back after business hours! Great voice!)

It slid right back into place with no issues. I got 4 of the six Torx screws back in (2 on top and 2 on bottom) but I just can't get those 2 middle ones, in the long deep slots, into place. I gave up after 90 minutes. I was going to try and glue them to my Torx driver but then on the last two attempts, I dropped the screws. I spent another 20 minutes trying to find them. They did NOT hit the floor. I have to figure something else out but in the meantime, does anyone know the thread pitch/length offhand or where I can get that spec so I can replace them, if I can't find the other two?

Oh..and if you're attempting this, watch the fins on the power steering cooler..they are razor sharp. I shaved a good bit of the hair off the back of my hand/arm..and a bunch of skin as well.

I'm going to try to find the screws tonight and if so, will enact my plan B of rubber-cementing them to my driver.

Appreciate all the advice, assistance and moral support. Last night it took a bunch of Dewars to get over that experience!
Not that anyone is interested anymore, but today, I finally got the ABS module back in place. Unfortunately I never did find the two lost screws. I'm reasonably certain that someone in an alternate universe found these things and is wondering where they came from. Anyway, 8 bucks to GM and an 8 day wait and I got two screws.

I did use some rubber cement to glue the two middle and bottom ones to the unit and after ensuring that they would not fall out, I came home from work today and in 65 minutes, I got the part in. In looking for the screws however I pulled the entire airbox out, the bridge, the radiator cover, and anything that didn't require draining or bleeding, so I cleaned the filter and the maf, and reassembled everything.

My hand is pretty carved up thanks to the razor sharp fins on the power steering cooler, but at least no blood dripping anywhere.

I hooked up the battery...and voila! In 5 seconds, the warning lights went off and so did the codes! Thanks EVERYONE for the advice and tips. Thanks to Brandon at ABSFIXER too!!!

Now ..onto a well deserved cocktail!


Last edited by HTWHLS; 04-05-2012 at 06:59 PM. Reason: shout out to Brandon
Old 05-02-2012, 04:38 PM
  #26  
DBL "D"
1st Gear
 
DBL "D"'s Avatar
 
Member Since: May 2008
Posts: 1
Likes: 0
Received 0 Likes on 0 Posts
Default

Great write-up. Can I get the version with the pictures? Much appreciated. derek.dennis99@yahoo.com
Old 05-06-2012, 09:06 AM
  #27  
Retrochevy
2nd Gear
 
Retrochevy's Avatar
 
Member Since: May 2012
Posts: 2
Likes: 0
Received 0 Likes on 0 Posts
Default

Bill - I purchased a 1998 Corvette Convert. - It was delivered with a bad EBTC module - I know NOTHING ! - What is the relationship between the EBTC module and the ABS system ? - I have been told that this is a safety issue - I can not find a EBTC module anywhere - The vehicle was delivered by the dealer with the bad EBTC module - Any suggestions ? Thanks Dave -

Originally Posted by trussme
FIRST! if you want the photos referred to in this tutorial, PM me your email address

The Basics

Let's cover some basic information on AH, TC, and ABS. In simple terms, these three systems combine data from wheel speed sensors, yaw rate sensors, steering wheel position sensors, along with brake and throttle inputs to determine what the driver wants to do and detects any lose of traction and take corrective action by pulling back on the throttle, activating brakes on individual wheels, or releasing brake pressure as needed to maintain traction.

What goes wrong?

When there is a problem anywhere in the system, the computer does not know what's going on with the car or cannot respond correctly. Rather than risking the wrong response, which could potentially wreck you car, the whole system is simply disabled for the remainder of the ignition cycle. At this time you will see the ABS and Traction Control warning indicators illuminated on the instrument cluster along with the following messages on the Driver Information Center (DIC):
- Service ABS
- Service Traction System
- Service Active Handling

At this point, you can safely continue to drive your car, just remember that your electronic driving aids are no longer functioning so you should adjust your driving habits accordingly.

Troubleshooting

As I said before, when there is a problem the system is deactivated for the remainder of the ignition cycle, so sometimes everything will go back to normal if you just turn off the car and restart it. If that corrects the problem, it was either a glitch in the system, a lose connection that's going to come back soon or an early sign of a future failure that is coming. Even though the system is now functional it is still beneficial to continue to trouble shoot. The history code should give you a good idea of what to check

The next step is to see where the fault is. If you have several different codes write them down, clear them, and see which ones come back the next time you start the car. At this point, I'm betting that the codes point to either the EBCM or the wheel speed sensors. We'll get to the wheel speed sensors later, for now, let's get to the EBCM.



THE SYSTEM


The "system" that provides functions such as Anti-lock Braking and Traction Control is made up of two major parts ... the EBCM (Electronic Brake Control Module) and the BPMV (Brake Pressure Modulation Valve).

EBCM - This is the computer that receives input from sensors such as the wheel speed sensors (one sensor per wheel) and then decides when and how to "intervene" to unlock a wheel that has stopped spinning under heavy braking, for example. The most common code for the EBCM is C1214 - Sol Valve relay Contact or coil CKT Open. This code is set when the system voltage is less than 8 volts for 0.23 seconds.

BPMV - This unit has a pump and a series of valves. It is connected to the brake lines from the Master Cylinder and is then connected to the four brake calipers.

Under normal braking the BPMV valves are "open" so that brake fluid just passes straight through it and the calipers respond to your foot pressure on the brake pedal.

Should the EBCM decide it wants to take control of a caliper, say for ABS, the EBCM starts the pump in the BPMV and using solenoids it can change the valve layout so the EBCM can control brake pressure to that caliper. Using the pump and valves the EBCM can use the BPMV to decrease and increase brake line pressure to that caliper.

The C1214 indicates that the relay inside the EBCM that powers up the BPMV pump and the solenoids in the BPMV has failed. Without this relay the EBCM cannot power up the BPMV components when needed. That is why the C1214 causes the loss of all the systems that require control of brake line pressure. You have lost ABS, Traction Control, and Active Handling. You have also lost Dynamic Rear Proportioning and Rear Stability Control if your car is a 2001 or newer, though you won't see warning messages for those systems.

Since our goal is to fix this for the lowest price possible, we'll start checking things we can fix for free.
The EBCM sits between the engine and radiator.


You can see it in the picture on the below. The EBCM is on the left with the large wire harness coming into it and the sticker on top. The Brake Pressure Modulator Valve (BPMV) in on the right with the brake lines coming out. The EBCM is a dry module, meaning that you can change it out without having to worry about bleeding the ABS system. All of the brake fluid is contained within the BPMV (Figure 1 – EBCM (Left) and BPMV (right)). The coils (seen in the picture on the below, (Figure 2 – Coils) fit over small spools that have valves inside them. The valves are operated by an electromagnetic field supplied by the coils.

Start by doing a quick visual inspection of the wires. If there are any obvious signs of damage, you've likely found the problem. One member had a problem with the wires rubbing the serpentine belt

Also check to make sure the wire harness has a good connection. If the connection appears solid disconnect it (see step 3 in the replacement instructions below) check the pins to ensure that they have not been bent or damaged in any way. If there is any sign of corrosion, clean it off. Once everything looks good, reseat the harness.

Next, let's move on to the grounds. The EBCM is grounded to the chassis on the left frame rail, just forward of the engine. It's the Black box right in the middle of the picture. As you can see, it's real easy for dirt and moisture to get in that area which isn't exactly good for electronic components. Even if you never drive your car in the rain, it'll still get wet when you wash it, and that could be enough
Start by unbolting the chassis ground (Figure 3 – Unbolt Chassis Ground), and then take the chassis ground connector apart.



The next set of pictures (Figure 4 – Chassis Ground Connector 1, 2, 3 and 4) show the corrosion that can build up in the ground connector. If you chassis grounds look like this one, you've probably found the problem. Even if they don't, go ahead and clean it up with a wire brush before putting it back together. Also clean off the chassis and bolt to make sure you've got a good clean ground.

*If you are having any other electrical issues, it's a good idea to check the grounds. These pictures show where the other grounds are. (Figure 5 – Chassis Ground Locations)


It's unlikely, but before you break out you credit card and forking over your hard earned money, it's a good idea to check the fuses. One fuse box is located under the hood beside the battery; the second one is under the passenger side of the dash. Remove the floor mat and you will see the access panel. Just pull the fuses out and do a quick visual check.
On the left, you see a good fuse (Figure 6 – Good Fuse); on the right is a bad fuse (Figure 7 – Bad Fuse)

At this point, we know all of the wires are good, but for some reason enough voltage is not getting to the system. It is possible that your battery is not functioning properly. If your battery is a couple of years old, has been drained and recharged a couple of times it might be a good idea to go ahead and replace your battery. This is a long shot for EBCM issues, but I think it's worth a shot before spending several hundred dollars for a new EBCM and you're going to have to replace it eventually anyways. Old batteries can cause a variety of minor electrical issues and you likely have a bunch of history codes for minor issues if the battery is causing the problem.
Electronic Brake Control Module
Now on the EBCM itself, if the electrical contacts (Figure 8 – Electronic Brake Control Module) inside the relay are dirty or burnt, the vibration from striking the module may change the symptoms or may clear them up for a while. This is by no means a fix or a cure all, in fact it could make it worse or it may not do anything, it's just something to try. Use a small plastic hammer or something similar; lightly tap the front of the EBCM on the lower right corner of the module. The area will be on the right hand side of the lower electrical connection seen in the picture below.

At this point, you’ve got to additional possibilities. Replace the EBCM or replace both the EBCM and the BPMV. The service manual calls for you to measure the resistance between each pump motor control circuit and the housing of the BPMV, if that checks our okay; you replace the EBCM if not you replace them both. Since most people do not have the equipment to do this the best we can do is to replace the EBCM. If that doesn't work, you'll have to go back and replace the BPMV. The procedure for replacing the EBCM is very simple. The only special tool you need is a T-20 Torx screwdriver.
I have a Craftsman tool set that has a 1/4" drive screwdriver with and adapter for many different size bit. Unfortunately, the adapter was too long to fit between the EBCM and water pump, so I purchased a set of Craftsman 5 pc. Torx screwdriver set that worked fine. A flathead screwdriver may also be needed to pry apart the EBCM from the BPMV
1 - make sure the car is off.
2 - You will probably need to remove the air bridge to get to the EBCM.
3 - Remove the wire harness by first removing the white plastic clip that locks it in place (I cut it off and replaced it with a zip-tie) (Figure 9 EBCM (Left) and BPMV (Right)), then lift gray handle and pull back on the wire harness (Figure 10 – EBCM Disconnected (Front View)). At this point, you will be able to see the second wire connection that is removed by pulling down EBCM. (Figure 10 – EBCM Disconnected (Front View))

The EBCM is on the left with the large wire harness coming into it and the sticker on top. The Brake Pressure Modulator Valve (BPMV) in on the right with the brake lines coming out.



4 - The service manual calls for you the remove the 2 insulator nuts that hold the BPMV to the brackets and lift the EBCM/BPMV out of the bracket. I do not think this step is necessary because there is plenty of room while it is still in the bracket and you do not gain much additional clearance since the brake lines restricts the movement.
5 - Remove the 6 T-20 Torx screws connecting the EBCM and BPMV - 1 on each corner and 2 on the sides (Figure 11 – Remove 6, T-20 Torx screws EBCM and BPMV).


6 - "Separate the EBCM from the BPMV by gently pulling apart until separated" - I should start laughing here, but it's not that funny. It's been my experience that anytime the instructions call for you to do something gently, nothing gentle is going to work. In this case, I had to use a flathead screwdriver to break the seal. Once it moved a little, the rest was easy. In addition to the rubber seal, each of the 12 holes you see in (Figure 10 – EBCM Disconnected (Front View)) has a peg in them from the BPMV. Don't go crazy, but be prepared to force them apart.
7 - At this point, all you've got to do is put it all back together. Push the new EBCM onto the BPMV.
8 - Replace the 6 T-20 torx screws
9 - Reconnect the wire harness
10 - Put the intake back on

At this point, the AH/TC/ABS should work normally. If not, you've also got a problem with the BPMV. Although you could replace the BPMV yourself, you have to bleed the ABS system, which requires Tech II. For those of you like me that don't have access to Tech II, you've got 2 options. Replace the BPMV yourself and tow the car to a shop with Tech II to have it bled, or just take it in to have the BPMV replaced. The advantage is that you've already done all of the trouble shooting so you want have to pay the mechanic to diagnose the problem for you.

Replacement part sources

New EBCM’s … below is a list of part #s. Check with
Fred Beans for actual price & availability ($650 to $1000)

Part Number: 10343433 All 2003-2004
Part Number: 12216561 All 2001-2002
Part Number: 9367071 All 1999-2000 w/o Control Active Brakes


An alternative to buying a new one is to have your original rebuilt.
Old 05-12-2012, 10:24 PM
  #28  
rootpooty
Burning Brakes
 
rootpooty's Avatar
 
Member Since: Sep 2010
Location: LaPorte Indiana
Posts: 901
Likes: 0
Received 1 Like on 1 Post
Default

where are the pictures?
Old 05-13-2012, 11:42 AM
  #29  
Retrochevy
2nd Gear
 
Retrochevy's Avatar
 
Member Since: May 2012
Posts: 2
Likes: 0
Received 0 Likes on 0 Posts
Default

Thank you so much for your help ! I have checked with a re-builder and they tell me this particular unit cannot be rebuilt - Thanks again...........Dave
Old 05-13-2012, 04:39 PM
  #30  
Chicago1
Race Director
 
Chicago1's Avatar
 
Member Since: Mar 2008
Location: Rio Rancho NM
Posts: 12,053
Received 321 Likes on 208 Posts

Default

Originally Posted by rootpooty
where are the pictures?
In his post it says to email him
Old 06-25-2013, 11:30 AM
  #31  
pgbwr
2nd Gear
 
pgbwr's Avatar
 
Member Since: Jun 2013
Posts: 2
Likes: 0
Received 0 Likes on 0 Posts
Default

I had the same problem, bad relay that is unserviceable. A company called "Automotive Scientific" can replace the relay for a reasonable price.
Old 11-24-2015, 02:20 PM
  #32  
BDL17
Navigator
 
BDL17's Avatar
 
Member Since: Jan 2015
Posts: 9
Likes: 0
Received 0 Likes on 0 Posts
Default Can't send PM for pictures, yur PM menu is full

Originally Posted by trussme
FIRST! if you want the photos referred to in this tutorial, PM me your email address

The Basics

Let's cover some basic information on AH, TC, and ABS. In simple terms, these three systems combine data from wheel speed sensors, yaw rate sensors, steering wheel position sensors, along with brake and throttle inputs to determine what the driver wants to do and detects any lose of traction and take corrective action by pulling back on the throttle, activating brakes on individual wheels, or releasing brake pressure as needed to maintain traction.

What goes wrong?



When there is a problem anywhere in the system, the computer does not know what's going on with the car or cannot respond correctly. Rather than risking the wrong response, which could potentially wreck you car, the whole system is simply disabled for the remainder of the ignition cycle. At this time you will see the ABS and Traction Control warning indicators illuminated on the instrument cluster along with the following messages on the Driver Information Center (DIC):
- Service ABS
- Service Traction System
- Service Active Handling

At this point, you can safely continue to drive your car, just remember that your electronic driving aids are no longer functioning so you should adjust your driving habits accordingly.

Troubleshooting

As I said before, when there is a problem the system is deactivated for the remainder of the ignition cycle, so sometimes everything will go back to normal if you just turn off the car and restart it. If that corrects the problem, it was either a glitch in the system, a lose connection that's going to come back soon or an early sign of a future failure that is coming. Even though the system is now functional it is still beneficial to continue to trouble shoot. The history code should give you a good idea of what to check

The next step is to see where the fault is. If you have several different codes write them down, clear them, and see which ones come back the next time you start the car. At this point, I'm betting that the codes point to either the EBCM or the wheel speed sensors. We'll get to the wheel speed sensors later, for now, let's get to the EBCM.



THE SYSTEM


The "system" that provides functions such as Anti-lock Braking and Traction Control is made up of two major parts ... the EBCM (Electronic Brake Control Module) and the BPMV (Brake Pressure Modulation Valve).

EBCM - This is the computer that receives input from sensors such as the wheel speed sensors (one sensor per wheel) and then decides when and how to "intervene" to unlock a wheel that has stopped spinning under heavy braking, for example. The most common code for the EBCM is C1214 - Sol Valve relay Contact or coil CKT Open. This code is set when the system voltage is less than 8 volts for 0.23 seconds.

BPMV - This unit has a pump and a series of valves. It is connected to the brake lines from the Master Cylinder and is then connected to the four brake calipers.

Under normal braking the BPMV valves are "open" so that brake fluid just passes straight through it and the calipers respond to your foot pressure on the brake pedal.

Should the EBCM decide it wants to take control of a caliper, say for ABS, the EBCM starts the pump in the BPMV and using solenoids it can change the valve layout so the EBCM can control brake pressure to that caliper. Using the pump and valves the EBCM can use the BPMV to decrease and increase brake line pressure to that caliper.

The C1214 indicates that the relay inside the EBCM that powers up the BPMV pump and the solenoids in the BPMV has failed. Without this relay the EBCM cannot power up the BPMV components when needed. That is why the C1214 causes the loss of all the systems that require control of brake line pressure. You have lost ABS, Traction Control, and Active Handling. You have also lost Dynamic Rear Proportioning and Rear Stability Control if your car is a 2001 or newer, though you won't see warning messages for those systems.

Since our goal is to fix this for the lowest price possible, we'll start checking things we can fix for free.
The EBCM sits between the engine and radiator.


You can see it in the picture on the below. The EBCM is on the left with the large wire harness coming into it and the sticker on top. The Brake Pressure Modulator Valve (BPMV) in on the right with the brake lines coming out. The EBCM is a dry module, meaning that you can change it out without having to worry about bleeding the ABS system. All of the brake fluid is contained within the BPMV (Figure 1 – EBCM (Left) and BPMV (right)). The coils (seen in the picture on the below, (Figure 2 – Coils) fit over small spools that have valves inside them. The valves are operated by an electromagnetic field supplied by the coils.

Start by doing a quick visual inspection of the wires. If there are any obvious signs of damage, you've likely found the problem. One member had a problem with the wires rubbing the serpentine belt

Also check to make sure the wire harness has a good connection. If the connection appears solid disconnect it (see step 3 in the replacement instructions below) check the pins to ensure that they have not been bent or damaged in any way. If there is any sign of corrosion, clean it off. Once everything looks good, reseat the harness.

Next, let's move on to the grounds. The EBCM is grounded to the chassis on the left frame rail, just forward of the engine. It's the Black box right in the middle of the picture. As you can see, it's real easy for dirt and moisture to get in that area which isn't exactly good for electronic components. Even if you never drive your car in the rain, it'll still get wet when you wash it, and that could be enough
Start by unbolting the chassis ground (Figure 3 – Unbolt Chassis Ground), and then take the chassis ground connector apart.



The next set of pictures (Figure 4 – Chassis Ground Connector 1, 2, 3 and 4) show the corrosion that can build up in the ground connector. If you chassis grounds look like this one, you've probably found the problem. Even if they don't, go ahead and clean it up with a wire brush before putting it back together. Also clean off the chassis and bolt to make sure you've got a good clean ground.

*If you are having any other electrical issues, it's a good idea to check the grounds. These pictures show where the other grounds are. (Figure 5 – Chassis Ground Locations)


It's unlikely, but before you break out you credit card and forking over your hard earned money, it's a good idea to check the fuses. One fuse box is located under the hood beside the battery; the second one is under the passenger side of the dash. Remove the floor mat and you will see the access panel. Just pull the fuses out and do a quick visual check.
On the left, you see a good fuse (Figure 6 – Good Fuse); on the right is a bad fuse (Figure 7 – Bad Fuse)

At this point, we know all of the wires are good, but for some reason enough voltage is not getting to the system. It is possible that your battery is not functioning properly. If your battery is a couple of years old, has been drained and recharged a couple of times it might be a good idea to go ahead and replace your battery. This is a long shot for EBCM issues, but I think it's worth a shot before spending several hundred dollars for a new EBCM and you're going to have to replace it eventually anyways. Old batteries can cause a variety of minor electrical issues and you likely have a bunch of history codes for minor issues if the battery is causing the problem.
Electronic Brake Control Module
Now on the EBCM itself, if the electrical contacts (Figure 8 – Electronic Brake Control Module) inside the relay are dirty or burnt, the vibration from striking the module may change the symptoms or may clear them up for a while. This is by no means a fix or a cure all, in fact it could make it worse or it may not do anything, it's just something to try. Use a small plastic hammer or something similar; lightly tap the front of the EBCM on the lower right corner of the module. The area will be on the right hand side of the lower electrical connection seen in the picture below.

At this point, you’ve got to additional possibilities. Replace the EBCM or replace both the EBCM and the BPMV. The service manual calls for you to measure the resistance between each pump motor control circuit and the housing of the BPMV, if that checks our okay; you replace the EBCM if not you replace them both. Since most people do not have the equipment to do this the best we can do is to replace the EBCM. If that doesn't work, you'll have to go back and replace the BPMV. The procedure for replacing the EBCM is very simple. The only special tool you need is a T-20 Torx screwdriver.
I have a Craftsman tool set that has a 1/4" drive screwdriver with and adapter for many different size bit. Unfortunately, the adapter was too long to fit between the EBCM and water pump, so I purchased a set of Craftsman 5 pc. Torx screwdriver set that worked fine. A flathead screwdriver may also be needed to pry apart the EBCM from the BPMV
1 - make sure the car is off.
2 - You will probably need to remove the air bridge to get to the EBCM.
3 - Remove the wire harness by first removing the white plastic clip that locks it in place (I cut it off and replaced it with a zip-tie) (Figure 9 EBCM (Left) and BPMV (Right)), then lift gray handle and pull back on the wire harness (Figure 10 – EBCM Disconnected (Front View)). At this point, you will be able to see the second wire connection that is removed by pulling down EBCM. (Figure 10 – EBCM Disconnected (Front View))

The EBCM is on the left with the large wire harness coming into it and the sticker on top. The Brake Pressure Modulator Valve (BPMV) in on the right with the brake lines coming out.



4 - The service manual calls for you the remove the 2 insulator nuts that hold the BPMV to the brackets and lift the EBCM/BPMV out of the bracket. I do not think this step is necessary because there is plenty of room while it is still in the bracket and you do not gain much additional clearance since the brake lines restricts the movement.
5 - Remove the 6 T-20 Torx screws connecting the EBCM and BPMV - 1 on each corner and 2 on the sides (Figure 11 – Remove 6, T-20 Torx screws EBCM and BPMV).


6 - "Separate the EBCM from the BPMV by gently pulling apart until separated" - I should start laughing here, but it's not that funny. It's been my experience that anytime the instructions call for you to do something gently, nothing gentle is going to work. In this case, I had to use a flathead screwdriver to break the seal. Once it moved a little, the rest was easy. In addition to the rubber seal, each of the 12 holes you see in (Figure 10 – EBCM Disconnected (Front View)) has a peg in them from the BPMV. Don't go crazy, but be prepared to force them apart.
7 - At this point, all you've got to do is put it all back together. Push the new EBCM onto the BPMV.
8 - Replace the 6 T-20 torx screws
9 - Reconnect the wire harness
10 - Put the intake back on

At this point, the AH/TC/ABS should work normally. If not, you've also got a problem with the BPMV. Although you could replace the BPMV yourself, you have to bleed the ABS system, which requires Tech II. For those of you like me that don't have access to Tech II, you've got 2 options. Replace the BPMV yourself and tow the car to a shop with Tech II to have it bled, or just take it in to have the BPMV replaced. The advantage is that you've already done all of the trouble shooting so you want have to pay the mechanic to diagnose the problem for you.

Replacement part sources

New EBCM’s … below is a list of part #s. Check with
Fred Beans for actual price & availability ($650 to $1000)

Part Number: 10343433 All 2003-2004
Part Number: 12216561 All 2001-2002
Part Number: 9367071 All 1999-2000 w/o Control Active Brakes


An alternative to buying a new one is to have your original rebuilt.
Can you send me the photos. Tried to PM you, but it says your PM is full.

jdlund17@msn.com

Thanks
Old 11-25-2015, 12:04 PM
  #33  
jimcork1
Drifting
 
jimcork1's Avatar
 
Member Since: Jan 2001
Location: Slidell La
Posts: 1,347
Received 3 Likes on 3 Posts

Default

So my take is still no help on 99 C5 ABS for repairs or replacement? Is this still correct?


Thread Tools
Search this Thread
Quick Reply: ABS module question



All times are GMT -4. The time now is 12:09 PM.