This past week my DIC displayed the ABS/Traction control service required message along with TCS code C 1214. The code would not clear. I took the car to the local Chevy dealer and was told the Body Control Module needed to be replaced. They said the cost of the part was $940.00 which I thougt was high so I declined the service. I have since found the part at GMpartsdirect.com for $165.80 but I have a couple of questions.

1. Do you think their diagnosis is correct?

2. It appears that replacing the BCM is pretty easy. Just some connectors and screws. Am I missing anything? Is it just a matter of swapping the boxes? I replaced a PCM on my truck and it had to have the VIN encoded to get rid of the check engine light.

Any help you can give is greatly appreciated. Thanks.

 

GKrenn

You can install the BCM into the car but GM will have to program it for you. I had my BCM go bad and was fortunate enough to read the service manual prior to installing it. When I had my BCM problems, I ordered my own BCM and had the local GM service center install and program it. It cost me $75 for the programming service. I got the BCM from Fitchners. Before you go replacing the BCM, I think the dealer is bolwing smoke up your tail pipe. I would check a few things out first

Let me dig into the service manual and I will find out what the code.

Ahh, C1214, Sol Valve Relay Contact OR coil CKT open.

Hmmm, looking at the schematic I dont see anything BCM related All that is in the circuit are the EBTCM module, a ground and some fuses. Here are a few things to check
ABS/RTD Elect MAXI fuse 20 amp.
ABS MAXI FUSE 40 amp.

Disconnect the battery and see if the code goes away.

The conditions for setting the code are:

Anytime the solenoid valve relay is commanded on and the solonid valve relay voltage is less than 8 volts DC and the ignition voltage is greater than 10.5 VDC.

I wouldnt replace the BCM!!! Not until you rule a few more things out!!!

Check the fuses and disconnect the battery for a few minutes and get back to me with the results.

There is also a ground that you will need to check later!!!

BC

 

Always remember, dealers are famous for throwing parts at a car until the lights go out. They start with the most expensive and work backwards, if they had the chance they would rebuild the car at your expense. Look for the simple things first and work upwards. Start with grounds and loose wires or broken wires. Then work towards the sensors and modules, last is the computers, the BSM is a computer.

 

Thanks for the help, Bill. Are the fuses a visual check or is there some procedure. I will take a look at them tomorrow morning and let you know what it find out.

 

The mini & MAXI fuses are in different color clear plastic. You can see the fusable link through the plastic but I have seen fuses that look good and were really BAD.
The best way to check the fuse is with an ohm meter. You should have ZERO resistance if it is good and you will read INFFINITE it is BAD.

The visual method of checking is usually alright! If the fusable wire inside the plastic is broken the fuse is BAD!


[Modified by Bill Curlee, 6:48 PM 7/7/2004]


[Modified by Bill Curlee, 6:49 PM 7/7/2004]

 

Thank you, I will let you know what I find out tomorrow. You've been a great help.

 

all fuses are ok. What is my next step? Thanks

 

The next is to check the wires for loose connections and bad grounds, start at the sensor and work back to the BCM.

 

How good are you at using a volt ohm meter??? You will need to obtain a volt ohm meter because we are going to take some voltage and resistance readings at the Electronic Brake Traction Control module EBTCM and the Brake Pressure Modulator Valve BPMV wiring harness and plugs.
Please let me know if you have a front or rear mounted EBTCM. It is easy to tell. the rear one is mounted on the back of the differential and the front mounted one is in front of the engine on the drivers side. It will have a ton of brake lines going to and from it!

Before we get started taking things apart please disconnect and reconnect the battery to be sure that there isnt some programming glitch. Believe me,, sometimes this works and then ckeck the ground wire to make sure it has a GOOD connection to the frame rail. Recommend removing it and cleaning the connection and frame rail. G-102 is on top of the passengers side frame rail just aft of the head light motor assembly and below the coolant tank. It will be a stud with a black ground wire secured by a nut. SOAK IT IN WD-40 before you remove it!!

Do all of that and let me know what you find,

BC

 

Wondering if you had any luck with the procedures that I gave you last night?

Hope they work for you!

BC

 

Bill, I couldn't get connected this morning to get your post. My EBTCM is front mounted. I will try your procedures first thing Saturday morning and let you know the results, good or bad. I spent sometime today looking for the ground around the EBTCM. After seeing your post I now know I was in the wrong place. Thank you very much for your patience, I really do appreciate the help. I think I will be in the market for a factory service manual. Oh, and I do have a multi meter, will just have to be walked through the items to check. Again, Thanks

 

Bill, I disconnected the battery for about 20 minutes and removed the nut on the ground stud and cleaned the two spaded connectors and the base of the stud with a wire brush. The stud was firmly attached to the frame rail. I reconnected everything and still get the code.

 

I see Bill is taking good care of you but if you are placed in a bad spot and could use a little help I live in Memphis and can try to help you out, I'll PM my phone number to you if you want to set something up.

 

Thanks for the offer, I may have to take you up on it. Or if you know a shop that can be trusted.

 

GK

My IM was disabled (because of the new forum format) and I may nave not gotten your post.

Please let me know how you are making out with the instructions that I gave you.

BC

 

I disconnected the battery for 20 minutes while I removed the ground nut and cleaned all the connections with a wire brush. Checked the stud and it was secure. Connected everything back and still get the code and lights.

 

Later tonight I will break out the service manual and get you started troubleshooting the circuits.

BC

 

Bill, any chance to give further advice.

 

Glenn

The EBTCM is really two modules! The EBCM and the BPCM The BPCM is a NON SERVICEABLE unit that is connected to the EBTCM. There are 4 screws that hold the two halves together. The manual directs the tech to remove the unit to service it. That would require removal of 6 brake lines. I would clean the area around the parting line of the module and the plug and see if it can be seperated while it still is connected to the brake lines.
The two modules need 12 VDC from the two fuses and Ground

Grounds are known problem areas on corvetts and it is highly recommended that anytime that there problems, the module grounds should be cleaned, examined and the crimped on ground eyelet replaced if necessary by SOLDERING on a new one.

The ground for the rear mounted EBTCM is G-402 which is located on the rear passengers frame rail in the wheel well behind the rear tire.

The ground for the front mounted EBTCM is G-101 which is located on the top of the front drivers frame rail inboard of the front of the windshield washer fluid storrage tank. I may have misstated the location of this ground location in other post :bb .

The shop manual calls out the use of a special pin out box for reading the values. I will tell you what the numbers or letters are on the plug or circuit board and back that up with the color of the wire going to that pin or plug. That way you will not need the pin out box.

All readings will be referenced to GROUND unless specified other wise. Make sure that you use a GOOD clean ground!!!

Alright, here we go!

Disconnect the EBTCM plug. Using the DC volt meter, volts position (scale that will read 12 volts DC), read the following pins on the wiring harness with the ignition in the ON/RUN position (engine OFF). You must get "battery voltage" If the battery is reading 11.7 volts, you will/ should see 11.7 volts at these pins
a. D = Battery Positive voltage (solenoid voltage) red wire
b E = Battery Positive voltage ( pump motor) red wire
c A = Ignition positive voltage. brown wire

Switch the meter to the restistance/Ohm position and go to the megohm scale. With the ignition OFF, read the pin B to ground. Black wire with white stripe.
You should get VERY close to ZERO ohms. (.01 -.02 will be OK)

Read pins D to B. Should be infinite/open

LAST RESORT!

If the above readings are correct, you can seperate the EBTCM from the BPMV by removing the 4 screws. It should seperate in half by pulling directly apart. Do NOT twist or seperate the top or bottom only. There are two circuit board mounted plugs that the pins from the BPMV plug in to. Once the two module halves are seperated, check for dirt, corossion and damaged componets.
Read terminal 7 on the circuit board to the EBTCM case. Should read infinite/open.
If all of these readings are good. you will probably need a new EBTCM. If it were me, I would check the relay on the solenoid valve relay on the circuit board to make sure it is good. If you have to get this far I will give you other procedures!

The EBTCM and the BPMV should be able to be purchased seperately according to the shop manual.

Hope you find a problem somewhere else.

Please let me know if you have any questions.

BC