5.0_CJ

About 6 months into owning my '99 I randomly experienced Service Traction Control, Service ABS, Service Active Handling messages all appear on my DIC with the corresponding christmas tree affair of error lights.. since my car is a manual I would just cycle the key with the clutch out (effectively turning off and then jumpstarting the car) and they were gone... It didnt return for months... then it came back, and has started to get more and more frequent. Now, if I hit a bump or anything significant I get the Aurora Borealis on my cluster. I have yet to run the codes.. but my problem seems to be different from others in that I don't have the error constant, a bump or jolt causes it.. so I suspect I won't be seeing a dreaded C1214 code... I have been having battery problems lately, so I will be replacing it with a new optima, and I will check all the grounds to my EBTCM... but what I want to know is what else can I check while I'm at it... I understand there are some connectors on the hubs that run to the speed sensors... has anyone have some experience with this?

BlackZ06

Check to see if the car has stainless steel brake lines. The brake lines are ground for the wheel speed sensors, and some brands of lines do not provide a good ground.

First thing to do, though, is check the codes, that will give you an idea of where to start. The problem you're having could have 5,000 possible causes, the codes will narrow that down to a handful.

HTH

trussme

Read & Use this to fix your problem (its long! so copy & paste it somewhere):


Starting some time in 2005, I began to notice that many C5 corvette owners were having problems with the Active Handling, Traction Control, and Anti-Lock Brakes. Although there are many things that will cause the system to fail, it seemed that it was becoming more and more common for the Electronic Brake Control Module (EBCM) to fail, which can is very expensive to replace. In December 2005, I was faced with this problem myself. This guide was compiled from all of the information I gathered on the problem that helped my troubleshoot and correct the problem and is intended to help C5 owners avoid the insanely high cost of dealership repairs by showing how simple it actually is to fix the problem. Before we get started, I would like to thank Corvette Forum Member Bill Curlee for providing a wealth of information.

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 it by pulling the trouble codes from the DIC. 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.




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 Corvette forum 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 time or was made by AC Delco, 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. Directions HERE
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.
Directions for replacing the wheel bearings can be found HERE

Replacement part sources

New EBCMs. The two best prices I could find for new parts were Fichtner Chevrolet and Fred Beans. Since Fred Beans was unwilling to ship to my APO, I purchased a new one from Fichtner for $650 + shipping. 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.

Circuit Solutions
Price: $375 + return shipping
Warranty: 5 years
Website: http://www.modulemaster.com/

Auto and Truck electronics
Price: $425 + return shipping
Warranty: Lifetime
Website: http://www.autoecu.com/

The best place to get replacement wheel bearing/hub assemblies is Auto Zone. You're looking for the Timken brand ones. They are exactly the same as the OEM AC Delco bearings, but sold for about half the price (~$150 vs. $300+ from Chevy).

fuses are available at any auto parts store for, a set of various sizes should cost no more than a few dollars and should last a while.

Bill Curlee

WHAT DTC's are you seeing when the dash goes crazy?

I suspect that your not really having an EBTCM issue. If you were JUST having EBTCM codes and messages then I would suspect that it could be the EBTCM The codes will help prove his. Have you checked the battery cables for correct tightness?? 11 ft/lbs.

There have been cases where the BCM will cause all this rigamore! Check and see if the carpet in the passengers foot well or the area around the BCM is damp the next time this happens.

BC

BC

BC

atsugidad

Try this web site for EBCM Repair. Just found it posted here the other day. Much cheaper. $158.00

Plan to have mine repaired soon (02 Coupe). Have C1214 code for awhile now.


http://www.absfixer.com/

Phone # (877)648-7530

Phil

Bill Curlee

Unless the situation that caused the bent wheel also caused the wheel hub to go bad,,,I would say NO. Check for a bad wheel bearing by jacking up the wheel and wiggling it top to bottom looking for deflection.

You most likely have a bad connector. The female connectors are known to go bad. Do a pin pull test to see if the female pins in the female side of the connectors are bad.

It very difficult to damage a wheel speed sensor unless you cut the wire or have a bad bearing The almost bullet proof!







Inside the wheel speed sensor!





MALE CONNECTOR



BAD and GOOD FEMALE CONNECTOR

Bad one is on the RIGHT new one is on the LEFT



BC


BC