While driving my 1999 C5 I encountered a huge puddle with no option to turn around or back up my only option....pretend I was in a truck and keep moving. Well needless to say water got into the passanger floorboard. Almost immediately I was getting DIC errors saying reduced engine power, service tire pressure, low fuel, etc. I stopped for gas but when I went to leave......NOTHING. I could hear the fuel pump and one very faint click but that was it had to get a tow home and the next day I started troubleshooting. The BCM and fuse box in passenger footwell completely dry as far as I could see. So I pulled codes like many people on here say to do when **** doesn't work lol. I was getting a couple of U1064, U1000, and U1160 those were my only current codes as well as No comms to the BMC, HVAC, or RADIO. There is no security light when the car is off the lamps don’t come on when I open the door windows don’t roll up or down the hatch doesn’t pop from dash button, and I cannot lock my door from the driver side. This was 5 days ago!!! I have been scouring forums and have read 100s but to no avail.

I was working on the star connectors and when I pull the comb out of the #2 connector I can get data passing on the PCM to the BCM but not when I have it in same thing with a couple of others. but the comb isn't corroded it honestly looks brand new I saw in another post from almost a year ago where C5 Diag was helping the guy that said he "grounded" his BCM im wondering if that is something that is normal to do ... I cleaned off all of my grounding points but if there is a way to ground only the BCM I would love to try that.

If anyone has any tips I would love some help I hate not driving my car and can't wait to get it back on the road .... I also kind of went a little crazy wiping down the engine bay when I got discouraged with wiring and it is starting to shine again . Thank you in advance for any help.

 

My gut feeling is that the water has damaged the BCM, just because the BCM seems dry does not mean that water did not get inside. My advice is to pull the BCM and clean the PC board with alcohol, be very careful as the BCM has components that can be damaged by static electricity. There are BCM rebuilders that you can send your cars BCM for repairs. Good luck

 

Check the battery for 12.6 or more V across the battery cable attachments.

No? --load test the battery.

When checking or reinstalling the battery make sure the cable attachments and battery bolt posts are clean and the bolts are tight--11 foot pounds according to the FSM.

Report back.

 

Well since it has been sitting for a couple days now while I have been testing all the electrical it’s at like 7v any time I test it I will jump the car with another so I am getting a good 12v-13v and I will attempt to clean the bcm with isopropyl alcohol when I get back home are there any parts of the BCM I should avoid cleaning ?

 

Are you using a scan tool that can communicate with the modules and do you have a DVOM and know how to use it ???…what are you testing where you are seeing 7 volts ????

 

Testing the actual battery where should I check it ?
I don’t have a DVOM I was just using a micro meter

 

At 7 volts your battery is DEAD...recharge it and see if you have a parasitic drain somewhere...does your micro meter (do you mean voltmeter ??) have an ohm meter function ??...are you using a scan tool to see if you have module communication ??

 

when ever I get in it I hook it up to another car so I will have 12v-13v I just think it’s because I haven’t been able to start it in over a week. And have been trying over and over again to start it so it’s just low. But I do hook it up to charge whenever I’m using it and it’s showing 12v-13v whenever I start testing. Yes I mean voltmeter and it does have an ohm function. I do not have a scan tool but I am getting 0.2v-0.3v with I believe means that there is data passing because I don’t have a scope to visually see it

 

I think the quickest way to see if it's the BCM or PCM is to remove the "comb" from BOTH star connectors. The BCM and PCM must communicate with each other for the car to start...make yourself a jumper wire if you can and jump the dark green wire (PCM) to the light green wire (BCM) on the Star Connector #1...if the car won't start it's either the BCM or PCM...I've done this procedure on my car and the car will start...if your car does start we can check with the voltmeter and or ohm meter to see what module is causing the data bus issue !!...your PCM may have got wet too !!

 

okay 2 questions what kind of wire should I use to make the jumper wire and I might be wrong but I think the PCM is okay because I am getting codes from there so it is communicating while the BCM says no COMMs

 

Whatever gauge wire that you see on the star connectors should be good enough !!…well you can just see what happens when you jump the wires.

 

okay i am going to try that when I get home I have duty today so I can’t go home

 

"Go Navy" !!!

 

So I have an update.....I tried to jumper my PCM and my BCM and nothing still won't start. But I found something very interesting ... there is no power to my fuses like any of them. My car still turns on(no crank) the lights and everything turn on but there is no power to any of the fuses. hopefully this is a very easy problem

 

which fuses ??…all ??…underhood or IPC (passengers footwell) ?

 

none of them

 

Is the battery fully charged ??…are all 4 battery cables ends (at the battery and at the starter solenoid and engine block clean and tight ??

 

yes they are im just very confused because everything still comes on

 

Ok, how are you checking these fuses ??…test light or voltmeter ?…some fuses are hot at all times and some require the key to be on !!

 

I am using a voltmeter and I checked all of them