Ok I will try to explain my problems as good as I can. (My english is not so great).

My Corvette -98 has been totaly rebuild for the 3 time whit new engine and lots of nice stuff. Maybe someone have seen it in the thread
"Remember the flat Black Corvette"

At first all my functions in the car as power windows,lights...everything workt fine.

But now allmost nothing works...power windows,lights......
The engine starter dont get a signal when turning the key.
The message "redused engine power" comes one time every time I turn the ignition on but disapers and no fail codes...
Steering lock dont work
Remote control dont work and cant find "fob training" only "Tire traning"
The Modul at the passanger feet(is it the BCM?) make a uncontrolled sound all the time and lights flashing when this happens.(Wrong att the module?)
Does the starter signal go true a module or a relae?

This is many questions but I need some tips or answer...

I have these codes:

40 BCM Body Control Module page 8-405 UTD Page 8-727 No comm,
60 IPC Instrument Panel Cluster page 8-508, U1160 HC Loss of Communications with LDCM, U1056 H Loss of Communications with RTD, U1040 H Loss of Communications with TCS,
99 HVAC Heater Vent-Air Conditioning page 1-118 No comm,
A0 LDCM Left Door Control module page 8-904 to 8-951, U1064 H Lost Communications with BCM,
A1 RDCM Right Door Control Module page 8-904 to 8-951, U1064 H Lost Communications with BCM
B0 RFA Remote Function Actuation page 8-676 No comm

 

given the wide array of problems, i would think it is something central like the battery or bcm. have you checked the battery, battery connections and ground for the battery neg. cable? make sure the battery is charged and the connections are clean and tight. also may be loose grounds elsewhere so it would be wise to check them all. try this thread for some good info.: http://forums.corvetteforum.com/c5-t...tml?forum_id=1

 

While it's possible your BCM is failing, the first thing that comes to mind is you may have a faulty ground that's causing the BCM circuits to behave erratically like you describe. You should check this sticky link which covers many electrical and ground issues and how to correct them.

http://forums.corvetteforum.com/c5-t...tion-long.html

It could be as simple as a corroded common ground point for the BCM, which I believe is located on the passenger footwell sidewall (can't recall at the moment). Good luck.

 

The No Comm codes are significant. Its not going to run if the BCM can't communicate. Is there any water on the BCM or was there any water on it? If so, the udders from the HVAC were/are probably plugged up. Before going any farther with diagnostics, do as the others suggested and check the battery, battery cables and grounds. The battery must have at least 12.5 VDC present with the engine and iginition off. The battery to starter cable connection too.. check to make sure its clean and tight.

 

Hi!
Thanks for all the help but the problems is still in the car.
I have checked all the grounds.

The center of the problem seems to be the BCM module.
For exemple when I connect the negativ on the battery, the starter works for 10-30sek...then the BCM module starts to "flink" "klicking" sound. Like a relea that switches Off and On fast. The starter and lights in the car works i seuquens with this klicking...and when it stops nothing works..
This will repeat it self when I disconnect the negativ and wait 5min and connect again.

Im going to try whit a other BCM box tomorrow. Just to check if it starts to "klick" to. Then I know if the problem is the BCM or in the car...

What do you guys think about that?

 

Wow.. Here we go again.. I really think you have an IGNITION SWITCH Problem.. I would remove your Ignition switch and do the Repair posted below. This is becoming more and more common as these cars age.. I had many of the same Problems & Symtoms you are discribing and Repairing my Igntion switch Fixed all.. See my posts on page 4. If you need help, I'll do all I can. If this repair works thank BILL CURLEE..

Here is the Link..

http://forums.corvetteforum.com/c5-t...ch-repair.html

 

Nice tread I will check my ignition switch. But today I tested a BCM module from a other corvette and the clicking went away
It seems like the problem was the BCM. But know we need to program the new BCM. Because I got the code P1631 HC.

Now to my new question.
My parking lights,headligts and interier panel lights dont work.
Does the BCM controll this to?
Will it work after we programed it?

Because it has worked before..

Thanks again for all the help!

 

You can't swap in another BCM and expect it to work. There are security issues that have to be programmed. The clicking you were hearing before in the passenger footwell was probably the TDR (Theft Deterrent Relay) which tells the solenoid to turn on, which then engages the starter motor.
The BCM (Body Control Module) controls lots of things inside the car including the HVAC, lighting, and so on....many things. As you already found, your BCM isn't communicating with everything else. Look in the passenger footwell for something called a "star connector" which I think is a black connector with gray wires going into it. Its basically a shorting bar which connects those gray wires together. Check to see if its properly seated.

 

I still think its your ignition switch.. I had the same P1631 Codes and many others on my Car too. When your Ignition switch has bad contacts, It does not get the Correct Voltage to the BCM and other areas of the Car and Causes HAVOC on the entire electrical system. Repair that ignition switch!

 

It`s NOT the TDR relay. It was the BCM modul 100% that clicked like crasy. And like I say before I will program it to my car.

The question was if the BCM controls headlights,parking lights and so on.

 

I will check my ignition switch today.

 

There certainly are relays in the BCM that could click

Just keep in mind that the BCM is extremely tough. Mine was buried in water due to the clogged udder thing. After drying, it has worked like a champ since.

My point is, go thru the electrical sticky as suggested thoroughly before you even think of replacing the BCM. If your BCM has been wet, open the case and check for corrosion, then dry the circut board thouroghly.

Please post your fix!

 

I checked my ignition switch today and I did find two burnt contacts. I repaired it so its like a new one now.
Then I tested my BCM module again to check if it worked. But it started to "click" like crasy again and everything whent on/off with the clicking...

I connected the "new" BCM module and it was silent... and it seems to work.
But I must test to program it first to se if all the light and stuff also works..

 

Like it was stated peviously, "just plugging in a DIFFERENT BCM and not hearing the noise tells you very Little...... Program the BCM to the PCm and see what you have. Like "slvrzo6" stated, it's vital to insure that EACH module has the correct power and grounds.

YES the BCM can control vehicle lighting. It is also controlled directly through the switch that controls that lighting. There parellel. EXAMPLE,, when you unlock the car,,,,,the parking lights come on as well as the interior lights. Thats the BCM working.

BC

 

I have checked that I have the correct power and ground in to tha BCM module contacts C1,C2 and C3.

Im going to try to program the module today but now Im woundering if the BCM is locked to the WIN number? Because the PCM is locked to this number I think...
Anyone how know this? Must I buy a new one from GM or can I reprogram this used BCM to my car?

 

Ok nobody who know this?

 

i did a google search and found this the BCM will need to be programmed and then RPO configured for your vehicle and the theft deterrent relearned.. i suggest you try a "bcm coding" search on google and see if you can find a how site.

 

Thanks. But now I have a Tech 2 and was going to reprogram my BCM box. But I cant find out how...
Can only find "BMC setup" and that I can choose some options like F45...and others.

But nothing about security or theft deterrent password incorrect.

 

Ok....this is my status right now......
I have tryed with a new BCM from a other Corvette and programed it with HP tuner. And tried with turning off the security options VAT.

Now I have no DTC codes......none....The P1631 HC has disapered.
But I can`t start the engine. Nothing happens when I turn the key.
The "Security" lamp blinks all the time and the steering lock dont lock or unlock....

I have checked the ignitions switch
I have checked all the grounds from powertrain to body and they are perfekt.
I have checked all the fuses.
I have checked every connection.
I have checked the star connections.

When the old box is connected I can crank the engine for 10-20sek. Then the BCM or some relay starts clicking everything on and off at the same time as the clicking. Like when the battery is bad...but I have power and good grounds.

Is the old BCM broken and the "new" (used from a other corvette) cant be reprogramed?
Or is there something Im missing?

Please someone help.
I cant find anyone here in Sweden that know this.


I cant find anything wrong and need Help with this.... The car is going to a car show next weekend and the time is running out.

Can I some how get pass this and take a "short cut" in worst case....just so I can drive the car.
If I set a ground to the Theft deterrent relay as a signal fron the BCM. Then the starter will work. But how about the PCM?....Will the engine start?

 

YOU C A N N O T program the BCM with HP Tuners.

You need to Sync the BCM to the PCM and program in the RPO Codes using the proper procedure with the GM Tech II or use the GM emergency procedure just to get it to run.

Thats your problem!

Heres the sync procedure for a new BCM.


BCM/PCM RELEARN PROCEDURE


You will need to conduct the PCM/BCM relearn process. This matches their handshake ID's and allows them to talk to each other.

Do this before you worry about VATS issues:

1. Turn on the key for 11 minutes.
2 Turn off the key for 30 seconds.
3. Repeat 1&2 two more times.
4. Turn on the key for 30 seconds.

The car should start and run with the new BCM. Good luck and report back on your progress.
Shirl
SD Racing Enterprises
Aguila, AZ
Coutersy of MrEracer


This will sync the PCM to the New BCM but all of your RPO options will not be retained. You will need a TECH II to program them into the new BCM.

Bill Curlee