C908

I installed a new Red Top yesterday to replace my 10 year old Red Top. Made sure it was charged up installed it being careful not to over tighten the connections.My car started right up so I thought all was good. I then discovered my key fobs were not working but I got them reprogrammed with no problems. Today when I went to go for a ride the car was dead and giving me some crazy readings. It said service vehicle soon, BCM No Communication, Code 1000 HC, Code 1160 HC. I decided to try unhooking the battery and re hooking to see if that might reset things. The soon as I started to loosen the negative cable the hood light came on,it was to loose but I tried to start the car and it tried for a second then nothing and the hood light went out. I just slightly started to snug the negative cable and the hood light came back on. This time the car started right up, went for 20 mile drive and all was good. Once back in the garage shut engine off and restarted with no issues. Key fobs are working and everything appears to be normal. Any ideas ? I haven't looked those codes up yet to see what they are. Again I would like to mention I did not over tighten the battery connections. Also my car is always hooked to a battery maintainer in an unheated garage. Thanks !

C908

Just looked up the codes, U1000 Loss of communication undetermined, 1160 Loss of communication with LDCM. I feel this some how is a result of having the old battery die and installing a new one but I'm just guessing. Any thoughts ?

foggy

Probably didn't have the ground tight enough is my guess..
Make sure the cables are very clean and the threads of the bolts too

C908

Thanks, I'll see what it does tomorrow. My connections are clean, if I have issues starting it I will try tightening the connections. I was afraid of over tightening so maybe that's my problem. The battery wasn't installed until the battery maintainer showed a full charge. Never had this problem with the old Red Top battery while my car was in storage with the maintainer hooked up.

BigGun

You are not likely to over tighten and strip the bolt. Both of the connections need to be tight or you will continue to have problems. I believe factory is 9 ft lbs which is more than just snug.

Cutlassmaster

11 ft lbs is what is called for if it's 03 and below. 04 switched to top post.

royal flush

Dont be concerned with torque specs--mechanics dont care--just snug it up and give it alittle extra--

royal flush

Do you think keeping old redtop on a battery maintainer gave it a 10 year life--did you always keep the maintainer when not driving car?

C908

Yes I always kept the old Red Top on a battery maintainer. I am a big believer in using battery maintainers on anything not used daily.

C908

Went out this afternoon and experienced the same thing as yesterday. Checked my codes and got the same codes. Opened the hood and hood light was not on, soon as I start to loosen the negative cable light starts coming on. Once the light stays on I have a connection and the car starts. I checked both positive and negative connections and they were clean. I decided to put dialectic grease on both connectors and make sure they were good and tight. Car fired right up so I cleared the codes and took it for a run out on the highway. I checked my battery read out and it was at 14.5. I put it back in the garage and hooked it up to the battery maintainer. I will try again tomorrow and hopefully it will start.

lionelhutz

It sounds like a bad connection.
Did you try to turn the cable after tightening the bolt?
Did you get the rubber boot over the cable end between the cable and battery?

C908

I believe I have everything the way it should be. I did not try and turn the cable but may do that tomorrow. I can't imagine it turning since I have tightened both bolts. I will report back tomorrow after I try and start it. I'm hoping the dialectic grease might help my connections.

royal flush

If cables are good and tight--its a short or bad ground wire--possible ign. switch--

C908

I know the cables are tight and everything is clean. I've owned this car for 18 years and it just turned 34,000 miles. If it doesn't start tomorrow I'm not sure what direction to go, any suggestions ? The codes I'm receiving just confirm there is a loss of communication. I'm hoping it's something simple like the connectors .

pjdbm

Have you taken the battery bolt out of the terminals and inspected? they come apart and you can actually get new battery terminal bolts.

From what you keep describing, that connection where you see the hood light flicker is an issue

C908

I actually tried to pull the bolts out but figured when they didn't come out they weren't removable. Is there a trick to getting them out ? Do you purchase the bolts from an automotive parts store or a GM dealer ? Mine really don't look bad but if I need to I would try switching out the bolts. If I open the hood tomorrow and the light is on I should be good. Otherwise I think the negative cable connection could be the problem. Thanks.

pjdbm

I am not saying this is definitely it but this is where I would be looking

pjdbm

I replaced mine, after 18 years, both bolts were rounded and I want a fresh set. You can get these anywhere for a few bucks each

C908

It's about 10 pm, I decided to go out and pop the hood and see if the hood light was on. It was on and I checked my cables for any movement, there was none. I know those bolts are tight this time so I hope all is good in the morning. I would have liked to have started it but my wife is sleeping. I feel pretty confident it would have started just now since the hood light was shining strong. Another weird thing I'll mention in regards to gas mileage. Every since I got my car out of storage several months ago my dash readout keeps telling me I'm only getting between 15 and 17 mpg. This afternoon when I checked it I was getting 24.5 mpg which is close to normal. The only thing I can think of is when the battery lost communication and threw a code along with giving me crazy messages I just cleared and reset everything. Don't know if that could of had an effect but just a thought. The last time I filled up and divided my gallons used into mileage driven I only got 16 mpg. I thought that was really bad considering about half was highway miles. Only thing I've done different is run Seafoam in the fuel.

C908

Everything was good this morning, car started fine. I took it out on the highway for about 35 miles. No issues so I'll keep my fingers crossed that a little dialectic grease and tightening down the terminals did the trick. I appreciate everyone's help on helping me solve this mystery. Thanks !