chris.quik

Hey everybody, I'm hoping I can get some help on an issue I've been having for the last few months. Both of the following gauge lights came on at the same time and have stayed on since:

"SERVICE ABS" and "SERVICE TRACTION SYS"

Some have told me that this issue could be triggered by faulty tire sensors, and some have told me that's not the case...

I have a 2000 Coupe, auto transmission, 52,000 miles.

Any help is appreciated.

Thanks,
Chris

lucky131969

Pull codes please............

coupeguy2001

If you get a C1214 code, it is the solenoid module on the ABS module in front of the engine on the right side just under the radiator hose.

KenShores

Check your battery first. How old is your battery?
Maybe take it to autozone or some place like that where they will check under load for free.

Optimus_C5

Tough to tell exactly what is causing the warning. I had it start intermittently 3 years ago and ended up having to have my EBCM repaired. Some have reported that after cleaning all the ground connections that solved their problem.

It's one of the electrical gremlins that is going to have you doing a lot of trouble shooting. There are a lot of great posts about your issue on the forum. One of the most respected and best at troubleshooting your issue is forum member Bill Curlee. Do a search of posts by Bill and you will find a ton of information about electrical troubleshooting.

trussme

if You want the PHOTOS that are (absent in the following guides) PM me your email address so I can send them to you....

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.
Wheel Speed Sensors
Back to the wheel speed sensors (Figure 12 – 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 you’re at it, this is a good time to upgrade the lug studs and add spindle ducts.







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.

For EBCM repair/replace for Years 2001-2004 ONLY
Call Brandon
877-648-7530 at ABS FIXER
or: www.absfixer.com
$150. plus UPS....warranted as long as you own it
OR…. get a REBUILT EBCM from these folks:
http://stores.shop.ebay.com/Digital-.../Homepage.html
http://www.autoecu.com/?gclid=CO-ozv...FR4UagodWwilqQ
http://www.speedometerrepairguy.com/

csc67

ABS Fixer (Brandon) only repairs ECBM for YR's 01-04

Bull_in_a_china_shop

You may want to investigate the grounds to make sure they are cleaned or replaced. There are 4 ground posts i believe that can freak out certain systems if they are fouled. Behind each headlight there is a post, under the battery and one more in the rear of the car-the exact spot escapes me. But often times people get short hex head self tappers and just attach the grounds to those since they are clean- and sink them.

cdkcorvette7

98turbls1

I was having the same issue on my old battery. I decided to go to an Optima red top and when I was changing it the ground was all kinds of corroded (just bought the car). Once I cleaned the grounds and put in the new battery I have not had it return one bit. Check there first since it's the easiest.

Lestat52

Like everyone is saying ...Pull the codes. I had that on mine and found it was a broken wire in the wiring harness going to the abs sensor on the front wheel. Fixed the wire,,,reset the codes....no more problems.

fred68

after a year of on and of problems,a new battery,abs fixwed by abs fixer,wire repair at ground junction, a new ignition switch electrical side for $70 fixed eveything/both end terminals on the 6 pins of the switch were burned

Bill Curlee

The only effective way to figure out what is wrong is to figure out what DTCs are triggered. Use the built in DTCs reading software and Read your DTSs :

READING YOUR Engine Diagnostic Trouble Codes (DTC)

This procedure should be carried out any time you experience a problem with your C5. Most inexpensive store bought aftermarket code readers will ONLY read power train DTC’s. Reading the DTC’s with the C5 built in code reader will allow you to read ALL the modules in the vehicle.

The Diagnostic Display Mode is entered with the following procedure:
1) Turn on the ignition but don't start the engine.
2) Press the RESET button to turn off any warning messages. (i.e. door open, trunk open ect)
3) Press and hold the OPTIONS button
4) While holding OPTIONS, press FUEL button four times within a 10 -second period.

Initially, the on-board diagnostics go into an Automatic Mode which will cycle through each module and shows diagnostic codes in a pre-set sequence: PCM - TCS - RTD - BCM - IPC - RADIO - HVAC - LDCM - RDCM - SCM - RFA. All codes will be displayed for each module. ( i.e. PCM = 4 codes) If none are present in a given module, you will see No More Codes on the display.

There are two types of diagnostic codes, Current and History designated with a letter suffix, “C” or “H”. A current code indicates a malfunction is present in the module displaying data. A history code indicates a problem existed sometime in the last 40 or 50 ignition cycles. When not accompanied by a current code of the same number, it's potential evidence of a previous problem, now resolved, that was not removed by clearing the codes. More likely it's an indication of an intermittent malfunction.

Intermittent codes are the most challenging of the diagnostics. An intermittent code may have happened once, may have happened more than once but is inconsistent or may be happening on a regular basis but not at the time the codes are displayed. History codes can also be caused by a current malfunction in a system that is not operating at the time codes are displayed. An example is the rear window defogger which doesn't operate until the Body Control Module detects engine rpm. For history codes set by a module that does not operate with the key on and engine off, a special diagnostic tool called a Scan Tester is necessary to properly diagnose the malfunction.

Once the system has displayed all modules, it goes into the manual mode which allows selection of each module using combinations of Driver Information Center buttons. Manual mode can also be entered during the automatic sequence by pressing any button except E/M. Once the display shows Manual Diagnostics, select a module by pressing the OPTIONS button to go forward or the TRIP button to go back. Once a module is selected, a code is displayed, and if more than one are present; press GAGES to go forward or FUEL to go back.
To exit the diagnostic mode at any time, press E/M. If you want to erase codes in a given module, press RESET To reset the codes once in manual mode, press and hold RESET until it displays NO CODES Press OPTIONS to go to the next module. Repeat the steps until you have reset the codes in all the computer modules.
NOTE!! Only reset the codes IF you want to - it is NOT necessary to do this. Clearing a code does not repair a problem. You are simply erasing the evidence of it in the module's memory. If you clear the code/s, and extinguish the Check Engine Light, your emissions status ready will NOT allow you to pass an emissions test until you have completed the required driving cycles. There are a few body module DTC’s that if set will prevent the module from operating properly. Once the DTC is cleared, the module will return to full function. This is not true for power train DTCs.

If you have never read and cleared your codes, there will probably be a lot of old history DTCs. It is recommended that you clear your codes and see if any come back during a driving cycle. Those are the ones that you need to concentrate on diagnosing.

Once you have the codes, the next question is: What to do with the information?
First, consult the factory service manual. Any serious C5 Do-It-Yourself owner should invest in the Corvette Service Manual of the appropriate model year. The Service Manual is really a requirement if you want to understand and work on your C5.

NOTE and a WARNING. You can read the DTCs while the engine is running. I pull mine up all the time while driving.
WARNING. Don’t become distracted while reading DTCs while your driving and cause an accident!!!!! Use common sense and drive safe.

These are some very good C5 Diagnostic Trouble Code (DTC) explanation web sites!!! They also explain how to read the DTCs
Here are some very good sites that explain what DTC mean:

http://www.gearchatter.com/viewtopic11755.php

http://www.obd-codes.com/trouble_cod...d-ii-codes.php

Make sure to include the H or C suffix when you post your DTCs!!

Jeffwilson34

I cant tell you how to service it but I will tell you that it is something you do not want to take lightly
GET IT FIXED ASAP

http://www.jeffsfireworks.com/wreck.htm

this is not just caused by the traction control problem it was several things that came together at the same time, but I am confident that had the traction control system not malfunctioned at the perfect time there may still have been as accident but I Also think it would have been less destructive.
All it takes in a bit too heavy a foot on the gas, slightly wet road, a few gravels on the road, and a slight curve. I am not sure of speed but I would say no more than 30-35 at most. My problem was much simpler than yours appears to be, it was a traction control plug that was not fully seated and lathed down. I know exactly who did it too.
That would be me!
Trust me its not worth the emotions you will go through if you love your car half as much as I do. I went from denial to anger to sad, to crying and everything in between.

dbfrdan

If you shut off the engine, does it reset? If so, make sure you pull the codes while the car is on and the service traction control is activated.

Blindfingers

My friends 2002 Vert has the issue with ATC and AH lights on and service vehicle soon message.
The dealer originally diagnosed a failed ABS modue (EBCM?) and he removed it and sent it to Brandon (ABSFIXER). Brandon noted that he did not see the most likely failure in the module but in case of an intermittent issue, he performed the rebuild anyway. Once back we reinstalled the module and have the same issue.

We read the codes and the only error message we get is "TCS 28 No Comm"

We pulled the ground and disconnected the battery for 15 minutes to no avail, once the care restarted, the lights and error message returned.

We'll check the wiring for visual damage but is there anything out there to check? I don't think he wants to throw money at the car.

Thanks all.
Bob

Bill Curlee

Bob

What DTCs other than NO COMMS do you see? Even DTCs for other modules.

Blindfingers

Hi Bill,
We've not seen any current codes being thrown. When the DTC does the auto everything but TCS has no codes.

Once the car is started, the ABS light will go out, then after a few seconds, both ABS and TC light.

We're going to dig deeper into the grounds and check fuses. Do you have any idea which pin on the ABS module plug to check to make sure we have power?

Thanks again,
Bob

wvufan1965

MTPZ06

My car just gave me this for the first time ever today...I hadn't driven it in about two weeks, so I was a bit concerned that the battery could be getting low. It started OK, but threw this Traction and ABS warning. I let the car warm up to operating temp, shut it off for 1 minute, and then started it again...no more codes. The car drove fine after that all day today... I may need to pick up a new battery in the not so distant future.