Meltdown! Seriously.
Thread Starter
Racer
Joined: Nov 2005
Posts: 404
Likes: 0
From: KY
Meltdown! Seriously.
Car was fine. Now car is not fine.
Yesterday I took my car out(04, mn6, bolton mods, only 7500 miles) for a quick spin without issue. Afterwards I decided to wash it. After a typical washing of the exterior I went to start the car and things went haywire. The car will crank and fire for half a second and immediately die. The power windows don't work, the power locks and mirrors do not work, the radio does not work, basically none of the power accessories. The DIC is currently flashing reduced engine power, low fuel, shocks inoperable(magnetic selective ride), service vehicle soon. When I access the onboard diagnostics it only says "no comm." after every subheading. I also hooked up a handheld obd2 scanner and it just flat out wouldn't read. So I took the wheel well cover off of the passenger front to inspect the computer(PCM) and it wasn't soaked in there, but there was a little water. I didn't do anything different washing my car, just a routine exterior wash. Call me crazy, but I think my computer is fried. If that's the case what is my next best move. Sorry about the length of this post.
PS. - Car is currently safe in my garage. I was able to push it in from the driveway.
Yesterday I took my car out(04, mn6, bolton mods, only 7500 miles) for a quick spin without issue. Afterwards I decided to wash it. After a typical washing of the exterior I went to start the car and things went haywire. The car will crank and fire for half a second and immediately die. The power windows don't work, the power locks and mirrors do not work, the radio does not work, basically none of the power accessories. The DIC is currently flashing reduced engine power, low fuel, shocks inoperable(magnetic selective ride), service vehicle soon. When I access the onboard diagnostics it only says "no comm." after every subheading. I also hooked up a handheld obd2 scanner and it just flat out wouldn't read. So I took the wheel well cover off of the passenger front to inspect the computer(PCM) and it wasn't soaked in there, but there was a little water. I didn't do anything different washing my car, just a routine exterior wash. Call me crazy, but I think my computer is fried. If that's the case what is my next best move. Sorry about the length of this post.
PS. - Car is currently safe in my garage. I was able to push it in from the driveway.
Tech Contributor
Joined: Dec 2003
Posts: 19,384
Likes: 87
From: Horncastle Lincolnshire, England
2023 C5 of the Year Finalist - Unmodified
You car is showing classic dead battery symptoms. Not surprising with a low mileage 04
To check your battery voltage, do not read the DIC when the car is off. The voltmeter is designed to measure alternator output when the car is running. It will always measure an inaccurately low voltage on the battery when the car is off. Anything from 11.0-11.9 is not abnormal in this mode. With the engine on, the voltmeter should show between 13V and 14.5V. A better reading can be measured at the battery terminals. Use a digital multi meter if you can. A fully charged battery measures approximately 12.66 V and a fully discharged battery measures about 11.86 V.
A recharge or a new battery will probably fix it.
To check your battery voltage, do not read the DIC when the car is off. The voltmeter is designed to measure alternator output when the car is running. It will always measure an inaccurately low voltage on the battery when the car is off. Anything from 11.0-11.9 is not abnormal in this mode. With the engine on, the voltmeter should show between 13V and 14.5V. A better reading can be measured at the battery terminals. Use a digital multi meter if you can. A fully charged battery measures approximately 12.66 V and a fully discharged battery measures about 11.86 V.
A recharge or a new battery will probably fix it.
Last edited by DeeGee; Aug 31, 2008 at 04:20 PM.
Team Owner
Joined: Sep 2001
Posts: 23,283
Likes: 906
From: Lake Elsinore, CA
I would check the battery - this sounds similar to that sudden wigout many of us here have experienced when the battery crosses that mysterious line and has enough voltage to register certain functions and go insane on the rest.
I'd have the battery load-tested to see if it's viable and check to see if it dropped a cell.
I'd have the battery load-tested to see if it's viable and check to see if it dropped a cell.
Team Owner
Joined: May 2006
Posts: 21,473
Likes: 356
From: Palmdale, Ca----- 2009 Cyber Gray 4LT A6 F55 452 RWHP 422 RWTQ- RIP 1998 C5 734 RWHP & 585 RWTQ-----
It seems as if something got wet that should not have!
I will suggest to take a close look at all your grounds because it sure sounds like a bad ground connection.
Check the CODES if you can access them and let us know what you get!
It will not be suprising to see that a ground has gone bad.
Thanks,Matt
I will suggest to take a close look at all your grounds because it sure sounds like a bad ground connection.
Check the CODES if you can access them and let us know what you get!
It will not be suprising to see that a ground has gone bad.
Thanks,Matt
Thread Starter
Racer
Joined: Nov 2005
Posts: 404
Likes: 0
From: KY
That's what my instincts said. I already replaced the battery and there is no change in conditions. The old battery was the original and I it had been cranking slow so I figured what the heck. The new battery had absolutely no affect. And as I said before I cant get the diagnostics to say anything other than "no comm." It doesn't give any current or history codes nor does it say no more codes, just no comm. I also tryed a handheld scanner and it could not communicate with the car, it just repeatedly froze up.
Tech Contributor
Joined: Dec 2003
Posts: 19,384
Likes: 87
From: Horncastle Lincolnshire, England
2023 C5 of the Year Finalist - Unmodified
That's what my instincts said. I already replaced the battery and there is no change in conditions. The old battery was the original and I it had been cranking slow so I figured what the heck. The new battery had absolutely no affect. And as I said before I cant get the diagnostics to say anything other than "no comm." It doesn't give any current or history codes nor does it say no more codes, just no comm. I also tryed a handheld scanner and it could not communicate with the car, it just repeatedly froze up.
Maybe not the problem but check the rubber bellows in the door hinges. Its been known for water to get in there and cause problems if the connections are loose.
Last edited by DeeGee; Sep 1, 2008 at 02:30 AM.
Burning Brakes
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From: Middle Of Kali CA
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Tech Contributor
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From: Charlotte, NC (formerly Endicott, NY)
If you got water in the data link connection (door wiring) and it is shorted to ground that can cause the symptoms you are seeing. That would explain the No Comm messages.
Bill
Bill
Team Owner
Joined: Sep 2001
Posts: 23,283
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From: Lake Elsinore, CA
So far, we have given you all the usual suspects - battery, grounds, PCM, door bellows . . . Typical when one of these monsters rears its ugly head.
The car wash may be just a coincident but I wouldn't rule anything out. I always work through in the sequence where I don't start changing parts until I've run out of diagnostic routines or something leads me to conclude a hardware failure is to blame.
The car wash may be just a coincident but I wouldn't rule anything out. I always work through in the sequence where I don't start changing parts until I've run out of diagnostic routines or something leads me to conclude a hardware failure is to blame.
Tech Contributor
Joined: Dec 2003
Posts: 19,384
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From: Horncastle Lincolnshire, England
2023 C5 of the Year Finalist - Unmodified
As Patches says, be logical. Start with the easy stuff.
Check the battery voltage
Disconnect the door bellows connectors and clean them up and dry them out. Some dielectric grease will help.
Check the grounds. The one on the engine side bulkhead behind the passenger headlight is a good start.
Only at that point do you want to start playing with other hardware such as PCM/BCM (major jobs).
You have the best of the Forum electrical gurus helping you out (and I don't put myself in that category)
Last edited by DeeGee; Sep 1, 2008 at 02:37 AM.
Thread Starter
Racer
Joined: Nov 2005
Posts: 404
Likes: 0
From: KY
First off I'd like to thank everyone for their responses.
I checked everything that was suggested. The car is 100% back to normal(hopefully it stays that way
). The harness that plugs into the bottom of the pcm was damp and the little rubber seal that is supposed to protect it was krinkled. After unhooking everything and blow drying it out the car returned to perfect working order. The only thing I can figure is the side cove cover is a little loose and water was getting in behind it and enough finally got in to cause a problem. I can't find any other cause. Happy for now though. If this problem rears it's ugly head again I know where to turn as always.
I checked everything that was suggested. The car is 100% back to normal(hopefully it stays that way). The harness that plugs into the bottom of the pcm was damp and the little rubber seal that is supposed to protect it was krinkled. After unhooking everything and blow drying it out the car returned to perfect working order. The only thing I can figure is the side cove cover is a little loose and water was getting in behind it and enough finally got in to cause a problem. I can't find any other cause. Happy for now though. If this problem rears it's ugly head again I know where to turn as always.
