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Any ideas? ABS light/Active Handling

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Old Sep 28, 2007 | 10:38 PM
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Default Any ideas? ABS light/Active Handling

I was sitting at a stop light today and my car told me to "check the ABS system" and "check active handling". Both lights on the cluster came on and the message displayed below. The car ran and stopped as well as ever.I drove to my destination and then parked for a couple hours. When I came out and started the car, no more "check" lights or issue. 25 mile drive home, never came back. Does anyone have any ideas as to what this may be? What's the best way to figure it out? Being intermittent, will a dealer have any idea? My car is a 54k mile 2002 MY coupe. The only mods done are a 160 thermostat,vararam intake, aftermarket air bridge w/ coupler, velocity stack, and hypertech tuner. I have the Z51 suspension package as well. Thanks in advance for your help!
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Old Sep 28, 2007 | 11:40 PM
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Start by pulling the codes
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Old Sep 29, 2007 | 07:14 AM
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Default This will help...

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.

Electronic Brake Control Module

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. 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 left 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. The coils (seen in the picture*** on the right below) fit over small spools that have valves inside them. The valves are operated by an electromagnetic field supplied by the coils.
***if you want pictures PM me your email address....




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, then take the chassis ground connector apart.


These pictures 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.





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, on the right is a 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.


Now on the EBCM itself. If the electrical contacts 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 screw driver. 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 to 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 airbridge 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) (picture 1), then lift gray handle and pull back on the wire harness (picture 3). At this point, you will be able to see the second wire connection that is removed by pulling down (picture 3).
4 - The service manual call 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 restrict the movement.
5 - Remove the 6 T-20 torx screws connecting the EBCM and BPMV - 1 on each corner and 2 on the sides (picture 2).
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 screw driver to brake 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 picture 3 have 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

picture 1 picture 2 picture 3


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.

Wheel Speed Sensors

Back to the wheel speed sensors. Code C1221 - 1228 indicate that one of the wheel speed sensors is either sending a bad signal or no signal. Start by checking the connections. The wheel speed sensors are integrated into the wheel bearing/hub assembly pictured below. The wire coming out of the back is the connection for the wheel speed sensors. Verify that the connector are not broken, damaged, or corroded in any way. Pay particular attention to the female end.




The wire coming out of the wheel speed sensor connects to and 18" jumper harness, then to the main harness. It is very common for people to have a weak female pin in one of those connections. If all of that checks out good, Swap the jumper harness from side to side. For example if the left front is bad, swap it over to the right front. and install the good one from the right front to the left side. Then clear the trouble code. If the trouble code is now on the right side, you know the wire harness is the problem. If the code is still on the left side after swapping the jumper harnesses, you know the problem is inside the wheel speed sensors.


If all the wires check out good, it's time to take a trip to Auto Zone for a new set of bearings. You can buy replacement AC Delco bearing from your dealer if you want to, or get the exact same bearing in a different box for half the price (~$150) from Auto Zone, you decide. The bearings should be replaced in axel sets, so if your left front is bad, you have to replace the right front too. While your at it, this is a good time to upgrade the lug studs and add spindle ducts.


Replacement part sources

New EBCMs. Below is a list of part #s and estimated prices from Fred Beans to give you an idea of what you should pay.

Part Number: 10343433
All 2003-2004: $465.58

Part Number: 12216561
All 2002: $610.16

Part Number: 12208997
All 2001: $612.80

Part Number: 9367071
All 1999-2000 w/o Control Active Brakes: $486.40

An alternative to buying a new one is to have your original rebuilt.
For EBCM repair/replace

Call Brandon

877-648-7530 at ABS FIXER



or: www.absfixer.com



$150. plus UPS....warranted as long as You own it
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Old Sep 29, 2007 | 08:01 AM
  #4  
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That's A Great Startring Point. Thanks And I May Need More But That Troublrshooting Help Is Wel Appreciated.
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Old Sep 29, 2007 | 10:08 AM
  #5  
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trussme should do a mass e-mail to everyone on the forum.

I just had the same issues and his step by step fix helped me with the replacement of the EBCM.

Now it seems like several people a week are having the same issue.
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Old Sep 29, 2007 | 11:01 AM
  #6  
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Originally Posted by bgray
I was sitting at a stop light today and my car told me to "check the ABS system" and "check active handling". Both lights on the cluster came on and the message displayed below. The car ran and stopped as well as ever.I drove to my destination and then parked for a couple hours. When I came out and started the car, no more "check" lights or issue. 25 mile drive home, never came back. Does anyone have any ideas as to what this may be? What's the best way to figure it out? Being intermittent, will a dealer have any idea? My car is a 54k mile 2002 MY coupe. The only mods done are a 160 thermostat,vararam intake, aftermarket air bridge w/ coupler, velocity stack, and hypertech tuner. I have the Z51 suspension package as well. Thanks in advance for your help!
Its normal for an intermittent problem to clear so the AH resets when you restart the car.

I think if you pull your codes you'll find you have a C1287 which is steering sensor rate malfunction

I've been having similar problems and like you its only when I come to a stop at the lights and its worse if I brake gently. Bill Curlee helped me trouble shoot it and I think I've tied it down to the steering wheel sensor. My wheel is fractionally off center which may be an issue or it may just be that the sensor is a bit flakey or even dirty.

Theres a thread somewhere on how to change it.

Mines very intermittent so I can live with it for the time being. if it gets much worse I'll probably change it.
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Old Sep 29, 2007 | 02:55 PM
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Any recomendations on which scanner I should get to read the codes? I figure I will someday need one anyhow so why not get it now? I doubt I need anything fancy.
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Old Sep 29, 2007 | 09:42 PM
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Bought a scanner,shows that the car has no codes. I guess I hope it was a fluke and wait to see if it does it again?
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Old Sep 29, 2007 | 09:50 PM
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I just got the same message last night. I turned the car off and then back on, everything cleared all was good. Today I went to a friends house to help him replace his wheel hub, because of a strong vibration. Well on the way home in my car, I made a hard right hand turn and i get a very strong vibration coming from the right front. I'm going to see if i can pull the code. I also printed this entire thread, to keep in the garage to do a step by step. Thanks for the information, Rouge Wave told me about this thread.
I pulled the code....28 TCS 1214

Last edited by GeorgeZNJ; Sep 29, 2007 at 10:01 PM.
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Old Sep 29, 2007 | 10:01 PM
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My car is a garage queen, seldom driven, and tends to show the same codes until the battery charges fully - typically after driving for a while. The battery tender does not always keep the voltage right. Try checking battery voltage - it does not take much droop in voltage to trip the codes.
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Old Sep 29, 2007 | 10:53 PM
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Originally Posted by Allzwell

trussme should do a mass e-mail to everyone on the forum.

I just had the same issues and his step by step fix helped me with the replacement of the EBCM.

Now it seems like several people a week are having the same issue.
I've been having the same problem for a few weeks with my '02. I happened to be near the place where I bought it last year. So, I thought I's stop in. Though they don't really service Vettes, but the mechanic pulled the code and my problem is related to the ABS system, some sort of pump. He said it would normally run about $1,100 to fix it, but my extended warantee should cover it. Now I just need to find the time to take care of it. Isn't that always the way???
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Old Sep 30, 2007 | 02:58 AM
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Originally Posted by mvarga
I've been having the same problem for a few weeks with my '02. I happened to be near the place where I bought it last year. So, I thought I's stop in. Though they don't really service Vettes, but the mechanic pulled the code and my problem is related to the ABS system, some sort of pump. He said it would normally run about $1,100 to fix it, but my extended warantee should cover it. Now I just need to find the time to take care of it. Isn't that always the way???
Dont trust a non specialist on this one. Read trussme's sumamry. Its all in there. You can spend many $$$ on components that dont ned changing. I've already had an EBCM and I'm no longer convinced that was the problem
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Old Sep 30, 2007 | 03:00 AM
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Originally Posted by bgray
Bought a scanner,shows that the car has no codes. I guess I hope it was a fluke and wait to see if it does it again?
Just pull the codes by using the onboard reader via the DIC. If it popped a warning you'll have an H code logged.

Heres How:

http://www.stengel.net/diccodes.htm
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Old Sep 30, 2007 | 03:01 AM
  #14  
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Originally Posted by GeorgeZNJ
I just got the same message last night. I turned the car off and then back on, everything cleared all was good. Today I went to a friends house to help him replace his wheel hub, because of a strong vibration. Well on the way home in my car, I made a hard right hand turn and i get a very strong vibration coming from the right front. I'm going to see if i can pull the code. I also printed this entire thread, to keep in the garage to do a step by step. Thanks for the information, Rouge Wave told me about this thread.
I pulled the code....28 TCS 1214
C1214 is often associated with an EBCM failure
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Old Sep 30, 2007 | 07:18 AM
  #15  
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Default That's THE ONE...

Originally Posted by DeeGee
C1214 is often associated with an EBCM failure
C1214....is the dreaded "defective relay-in-your-EBCM" Code! As of today, I have pasted or emailed my tutorial to over 125 Vette Owners on this Forum. I wonder if the C6 series is/will have this EBCM problem?
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Old Sep 30, 2007 | 09:37 AM
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Originally Posted by trussme
C1214....is the dreaded "defective relay-in-your-EBCM" Code! As of today, I have pasted or emailed my tutorial to over 125 Vette Owners on this Forum. I wonder if the C6 series is/will have this EBCM problem?
I have the code, 1214, but coupled with the fact that I get a very strong vibration when turning to the right, I'm inclined to think wheel hub/bearing? I guess my question is, would EBCM failure cause a vibration when turning? Thanks for your time.


edit: I just read the email pictorial that Bill sent me. Wow, this is great stuff. Thanks again.

Last edited by GeorgeZNJ; Sep 30, 2007 at 09:42 AM.
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