BCM and water

After Hurricane Ike disrupted our lives, my daughter can no longer start her 2001 Alero. Her car was parked in her apartment parking lot during the wind and rain that wreaked havoc everywhere.

The security light stays on and the engine initially starts and dies immediately. About 9 months ago she experienced the pass-lock mess and we successfully got her started with the 10 minute relearn process listed in the owner's manual. That no longer works.

In addition to not starting, the interior lights no longer come on, the door locks no longer work, the radio doesn't work, the door chime doesn't work and the trunk release doesn't work.

From what I can tell, it is quite likely that all of these may be remedied by replacing the BCM. However, what I have read indicates that it is common for water to leak onto the BCM and ruin it. What precautions can we take if we have it replaced to eliminate that potential hazard.

I can't help but think that with the way the wind and water was blowing with that hurricane that the water issue is a major contributing factor here.

Sorry to hear that. Start by checking for blown fuses associated with the body control module. The best way to tell if you have water intrusion at the area of the BCM module is remove the panels and do a visual inspection. The BCM module is located under the passenger side of the dash.

Other option is to take it to a GM dealer and scan for body/chassis DTCs. When a BCM is replaced it must be programmed using a GM Tech 2 scan tool.

Sorry to hear that. Start by checking for blown fuses associated with the body control module. The best way to tell if you have water intrusion at the area of the BCM module is remove the panels and do a visual inspection. The BCM module is located under the passenger side of the dash.

Other option is to take it to a GM dealer and scan for body/chassis DTCs. When a BCM is replaced it must be programmed using a GM Tech 2 scan tool.

The car is 25 miles from where we live. We found an independent shop we can tow it to where they said that if it is the BCM they can replace with a refurb. What are the pros and cons here vs going straight to a GM dealer?

Edit ... We do know that the fuse contacts in the driver side panel inside the car are corroded, but my husband checked fuses under the hood as well and said that nothing is blown. He didn't know at the time where the BCM module was located so he wasn't able to check for water intrusion there.

He can't get back over there until this weekend, to do additional troubleshooting, and she needs her car next Tuesday to commute 80 miles to school. We're afraid that he is not going to be able to handle this himself and are trying to decide whether to go with the independent shop or the dealer. :(

The pros of a GM dealer doing the work should be the ability to better or properly diagnose whether the BCM module is actually bad. Independents should have high end scan tools like the dealer's Tech 2 but cannot run specific tests or diagnostics per the factory service manual and sometimes the diagnostic trouble codes, if any, pulled up do not translate properly. So it may be hit and miss. The disadvantage of a dealer would probably be the higher cost for labor and parts. However, they can program the BCM to your year and options whereas the independent can get the BCM but has to find one that matches your Alero in year and options that were installed at the factory.

The pros of a GM dealer doing the work should be the ability to better or properly diagnose whether the BCM module is actually bad.

I wish I had been able to access the internet to get your reply before we had to make a decision about where to tow the car. This hit and miss phone and internet access, depending upon whether the phone company keeps fuel in their generators, is a bummer. However, I am so very thankful that we were minimally impacted by this hurricane compared to what many others are going through. My heart aches for all those who lost their homes or are displaced until who knows when.

We went with the independent and they have called back to say that they got the car running but I couldn't get a complete description as to what the mechanic had to do to get there (other than that he had to "bypass" the security system.)

However, now they want to know if we know the "code" for the Theftlock system for the radio, as it is "locked." We bought this car used from a dealer. My husband has worked on it many times during the past four years and has had the battery disconnected numerous times and never had the radio "lock" on him.

About two years ago, my daughter's boyfriend even tried to remove the radio to install an "upgrade" and had to back out of it because he didn't know what he was doing. Even with him messing with it, the radio did not "lock."

I am assuming that the Radio Theftlock system had been disabled before we bought the car since we have never had an issue with it. Does it makes sense now that all of a sudden the Theftlock system is kicking in? When you buy a new car do they give you this mysterious "code?" Or are you stuck with going back to the dealer to get them to unlock it for you when necessary?

They are also trying to determine why the door locks either lock or unlock ... but not the other. (I can't remember which one.) What are the possibilities here? Still pointing to the BCM?

...
The disadvantage of a dealer would probably be the higher cost for labor and parts. However, they can program the BCM to your year and options whereas the independent can get the BCM but has to find one that matches your Alero in year and options that were installed at the factory.

I think I have now run into another disadvantage of using the independent for this task. They have replaced the corroded BCM but have told me that when they finish with the car, I need to take it to a GM dealer to get the radio to work since it is "locked."

Since the 2001 Alero communicates between components to compare the VIN data in order for the radio to work without being locked by the TheftLock mechanism, I think a refurbished BCM is going to be a problem.

I ran across a bulletin through AllDataDIY that says that the VIN can't be entered into a module that previously had a different VIN entered. (Bulletin 02-09-41-001.) Somewhere in my reading, I thought I recalled that the VIN is programmed into the BCM.

Is it possible for a refurbished BCM to have the original VIN removed from it? Or is it possible that when they said they had ordered a part from Chevrolet that they actually purchased a "new" BCM and had it programmed before it was sent to them?

When a BCM is replaced it must be programmed using a GM Tech 2 scan tool.

Could you elaborate on what is actually needing to be programmed by the dealer? Can someone who does not work for GM purchase a Tech2 Scan Tool, or is that only available to those employed by GM dealers?

The independent mechanic replaced the BCM with a new BCM (without my knowing for certain that he was doing that instead of a "used" BCM.) From what I could tell in the few minutes I had access to the car before my daughter had to make a 160 mile round trip journey to school, all features that we were accustomed to were available and working (except the locked radio and the RKE.) Those features that had been problematic have been cleared up (except for the Security light that remains on solid.) Edit: The airbag light was on as well ... I just didn't notice it because the center of the steering wheel was in the way. When I contacted the shop manager to express my dismay that they sent me away with a non-functioning airbag system, he said that they were not aware of the situation. Thank goodness for the lights on the Instrument Panel. I would not have gotten to the dealer quite as quickly if I hadn't been aware of the airbag issue.


I know that I need to go to the dealer to address the radio, but what does the solid Security light mean if the car actually starts and runs? That I should expect the pass-lock stuff to possibly kick in again? Or that the pass-lock system is simply not functioning? (A true blessing if that is the case.)

I know the independent could not enter the VIN into the BCM and I wasn't able to find out if whoever sold this to them entered the VIN before they sold it to them. I ran across an AllData article on "DTCs Set When Replacing Modules" and it appears that if the VIN was not already entered (or doesn't match as in the case of a "used" BCM), a DTC B1001 Option Configuration Error would be set and the "Deployment of the airbags is inhibited." Should I assume that the seller did NOT enter the VIN when selling the module and the airbag issue is a real concern and needs to be addressed ASAP?

The GM dealership service departments use the Tech 2 scan tool since it is required for proper service of a GM vehicle. That scan tool costs over $5000 without upgrades so you are better off paying the dealership the hourly labor rate. It should not take that long unless they run into other issues.

A new Delphi BCM module off the shelf is not programmed. It must be done in the car. The VIN and an initialization-programming job is run based on your delivery options to include RKE, etc.

.... what I have read indicates that it is common for water to leak onto the BCM and ruin it. What precautions can we take if we have it replaced to eliminate that potential hazard.


The BCM that was removed from the car was in really bad shape from water intrusion. There were two pieces of tape applied to the case, I suppose to try to keep it tightly closed. Is that tape "normal" for the BCM case, or an indication that someone had used this to attempt to solve a water problem, prior to our purchasing the car four years ago?

Unfortunately, the tape wasn't helping much, as the case was actually somewhat warped and the top and bottom didn't line up with each other on one side. On the closure side, the case was warped and turned up at the corners.

Is it reasonable to try to seal the box up with something to waterproof it in the event we can't figure out where the water is leaking from? This car doesn't have the problematic moon-roof that others talk about. The only other source I have read about is for water to be driven in by way of the blower motor? Any other common things to check into?

In the event that the water intrusion can't be stopped, once the BCM begins to show signs of corrosion, is it possible to clean it with vinegar and reinstall it to avoid the buildup and eventual destruction of the module?

... That scan tool costs over $5000 without upgrades so you are better off paying the dealership the hourly labor rate. It should not take that long unless they run into other issues.

Oh my ... I wasn't planning to buy one. I just wondered if independent mechanics had access to them. If not... I would never go back to an independent for something that I thought might be computer related. I'm not a very happy camper right now. $485 for an incomplete job compared to the $525 quoted by the dealer. :headshake

It sounds like I need to get to the dealer right away to make sure the airbags work.

I did find one local shop, that was highly recommended, that does actually have a Tech2 scan tool and subscribes to the updates. They only install new BCMs and are able to program them.

If the shop has someone on staff who is GM certified, is it still better to go through the dealer in a case like this?

IMO it will be down to the cost but it is your decision. As long as the shop has the capability with the right scan tool and guarantees their work and gets the end product which is all issues resolved is what matters. Good luck!

The dealer quoted $98 to setup/program the BCM and the other shop is $92. It seems like no matter what decision I make these days, it turns out to be the wrong one. Maybe I should just toss a coin.:banghead:

Thanks for your feedback. I do appreciate your time as I try to work my way through this.

Logistics dictated which direction I headed. The dealer had me in and out in 2 hours and I no longer have a solid Security Light or Air Bag Light and the radio and key fobs work now. They even cut me a new master key and didn't charge any extra for it. I had priced one for the '89 Caprice recently and they said it would be $25. I'm glad they threw this one in for free.

On another note, I discovered that my daughter's original key is much more difficult to wiggle and jiggle to get it to work than mine is. The key lock cylinder needs to be replaced sooner rather than later. My husband did this for my other daughter's '99 Malibu but just transferred the existing pins to the new cylinder. When they say the key lock cylinder is worn out, does that mean you need to replace the pins as well? If so ... where to you get new pins?

When the dealer programmed the new BCM that was installed by the independent shop, I had asked for a listing of any historical or current DTCs. All I got was the following:

"Codes were Option Configuration and Low Voltage Codes -- all codes cleared"

I already expected the "Option Configuration Code" (which should have been B1001 related to the airbag deployment being inhibited because the BCM had not been programmed.)

Is the reference to "Low Voltage Code" related to the Security Light having been on?

Shouldn't there have been some type of code related to the fact that the radio was "locked?"

I don't understand why they didn't give me the exact codes, but I will take what I can get and be more precise the next time I ask for such codes.

Edit: We have tried to get our kids to keep their own manual records of maintenance procedures when they get my husband to do something for them. Unfortunately, that doesn't seem to be working and he doesn't do all of their oil changes. My daughter relies on the Change Engine Oil Indicator to alert her that she needs to get her oil changed. Did she lose that setting with the BCM replacement?

To the best of my recollection the oil change monitoring system is actually controlled by the PCM module - powertrain control module. It is best to stay with the good old 3K mile interval since the oil change warning system is unreliable.

The old history BCM codes were probably a result of the mechanics disconnecting the battery before starting work and since it was not initialized properly which will give a configuration error. Also, disconnecting the battery will cause the Theftlock issues on the radio.

..... It is best to stay with the good old 3K mile interval since the oil change warning system is unreliable.

Until I read the owner's manual I didn't realize that the "GM Oil Life System" calculated the oil change frequency based upon driving habits instead of just mileage. Are you saying that their "system" is "flawed?" It is a little scary to think that it might go a year without telling you that you need to change the oil. I can see how one would tend to hang onto the 3,000 mile interval.

"When to Change Engine Oil
Your vehicle has a computer that lets you know when to
change your engine oil. This is not based on mileage, but
on engine revolutions and engine operating temperature.
When the computer has calculated that the oil needs
changing, the GM Oil Life System will indicate that a
change is necessary. The mileage between oil and filter
changes will vary depending on how you drive your
vehicle -- usually between 3,000 miles (5 000 km) and
12,500 miles (20 000 km) since your last oil and filter
change. Under severe conditions, the system may come on
before 3,000 miles (5 000 km). Never drive your vehicle
more than 12,500 miles (20 000 km) or 12 months
(whichever occurs first) without an oil change."

The other problem is especially if an oil change/lube shop does the service they forget to reset the oil life monitoring system. Even DIY types forget about it.

Also, if you use extended life synthetic motor oils the system is worthless because most people use that type oil to go well beyond the standard 3K mile oil change interval.