Question-------------------------
Followup To
Question -
Due to a recent problem with both fuel and climate control units displaying a 'c', (and not being able to use climate control or fuel display) I replaced the BCM and ECM (BCM twice) with used ones. (also replaced the ECC panel) Finally regained control of the enviormental controls (ECC), with full function, but now the fuel unit displays a 'd'. I am at a loss to what is causing this problem. I cannot even use the diags to display codes because the fuel display keeps displaying 'd'. Any ideas would help. 1989 Caddy Deville 4.5Liter
Answer -
This is the MAJOR REASON that I NEVER EVER use USED components. You have NO WAY of knowing if these USED components are any good or NOT.
You could have a faulty ECM or a faulty BCM or a faulty component within the display.
Since the ECM is linked to the BCM and you have a faulty ECM it could destroy the BCM. If you have a faulty BCM it could destroy components within the ECM.
without testing each and every circuit of all the USED parts that you installed and NOT KNOWING if they are any good you have a MAJOR task on your hands.
I can provide you with a diagnostic diagram, But it is NO guarantee that the chart will resolve your problem due to the UNKNOWN condition of your USED components.
You will need to contact me at:
onlineautohelp@msn.com
In order for me to provide you with the information.
NOTE: This website is NOT mine and I am only a VOLUNTEER helping answer BASIC simple questions to those in need and this website does not allow pictures to be sent and or received.
Please include all of the information, MAKE, YEAR, MODEL, Engine size, transmission type and all necessary other information that you previously provided as well as the information that I just gave you when you contact me.
autohelp
Hello again.. (Caddy Deville 1989 4.5 Liter with auto )
As you mentioned above, when I atarted troubleshooting, I replaced the ECM and BCM as a pair just in case there was a problem with one or both, I did remember something awhile back the one unit could cause the other to fail, that is why I did it that way (and to save some $$$). I put all the orginal components back in and the orginal problem is re-curring ('c' on both fuel data display and the ECC display and both panels are un-responsive). I did disconnect one unit at a time (with ignition off) and see if problem went away, no avail. The only thing that did happen was when the ECC was disconnected the fan would stop blowing. Also while 'c' is being displayed, I noticed the cooling fans are running.
Every once in a great while, the system will work normal, then you here some relay clicking, displays will flash a couple times (and reset), and then the 'c' will come back. I am going to order a reman BCM from advance auto and try to see it this will correct the problem. Any help from anyone would be greatly appreciated (before I buy this BCM)
AnswerLet's say the ECM is frying the transistors in the BCM and you go ahead and install a NEW BCM and the ECM frys these transistors also. Then your right back where you started.
You will need to contact me at:
onlineautohelp@msn.com
In order for me to provide you with the information that will most likely resolve your problem.
The information comes right out of the GM factory service manual for your particular vehicle.
autohelp
