Won't crank, good battery
 

I had a rather strange experience with our '08 today. Wife started the car, drove about 2 miles and parked it. When she came back, it wouldn't start or even crank over. I went to her car and noticed that when I pressed the start button, the dash lights immediately went out. After some time, I decided to buy a new battery and I installed it. Still no crank. When the start button was pressed, the dash lights immediately went out and the car acted dead. After 5 seconds or so, the dash lights returned. We called AAA and the driver tested the battery and it seemed ok and then connected his jumpers to the battery. The behavior did not change. I tried several times. Just as a test, I moved the auto shifter, in case one of the switches was not working, but no change. Then, I decided to see if the car would go into accessory mode and it did. Then I shut off accessory mode and tried to start it - and it started right up.

Any explanations?

Later info:

Within a few days, the shifter showed serious problem, would only go into park and drive. Under a warranty, the dealer replaced the shifter and we have had not further problems for several years.

Ok, check through the back threads. I remember reading about A6 shift levers creating
some type of problem. (trying to remember)
Just remember that the whole shifter had to be replaced. Sorry I don't have time to check the threads now.

Still sounds like battery related issue. A "test" sometimes say "good" and it is a big fat lie!

Could be bad connection at the battery or starter.

Bad cable to or from the battery.

Elmer

Battery CABLE issue. Probably the ground. Sounds like you managed to get the bad connection to arc and weld but, if that is the case, it will happen again. Check the connections to the battery again and also the ground to the frame. You might be able to get it to go bad by just wiggling them one at a time and check for a start.

I had that happen to me at Talladega a couple of years ago on my 09 Z06. Pushed the start button, dash goes dark, and nothing happens. On the fourth try, it started. That was the one and only time it's happened in 3 1/2 years. I'm thinking some sort of computer glitch that self corrected.

I have an 07 A6 and have had this problem since the car is new - sometimes it happens once in a few months and sometimes once in a week. The dealer could never fix the problem while under warranty. Still have the original battery in the car.

More than likely you have a bad connection at the starter solenoid.

Anybody else have some thoughts? My best guess is that it is the battery ground and I intend to crawl under the car to check. It starts fine now but the problem will probably return.

Possible bad fob or battery....But the car will let you know...My dad has an alarm on the van if it is not disarmed the van does nothing battery is strong.

2005 Corvette sometimes no crank
 

I read the posts on this problem and I see all kind of advice that tells me some people don't know much about cars. I have the same problem with my 2005. First it is not a battery problem or connection at the starter. If you took out the starter and then tried to start all the lights would not go out you would just have no start. Any one with this problem do they notice that all the lights come back on in the same amount of time every time? I do not know what the problem is but I think it has something to do with battery protection circuit (so you can not run the battery down. This is a common problem with many years & I would think GM would of found a fix by now. My 2005 is a wreck (I have owned 17 Corvettes most with salvage title so I don't know if prior owner had same problem) that went thru chain link fence. The 05 will start many times then out of the blue you push starter button and all dash lights go out and same amount of time every time the dash lights come back on. The only good thing this happens at the shop ( where I doing the body work so it has not stranded my yet.

You guys might want to check the cable to the fuse box. It can look secure, but may actually have a connection loose enough to cause intermittent problems.

I have the answer, the freakin key FOB! Get rid of the FOB and all these stupid other problems go away! GIVE ME A KEY! IMHO!

I have an 06 and dealt with this 3 times. In all cases it was ultimately the starter. The solenoid integration with the starter broke loose and caused this exact issue somewhat sporadically...

Mine would not start when a phone charger was plugged into the center console !!!

I was the OP and I should have followed up as more happened later. I still do not have a good explanation but do have more information. We had no problems for a couple of months and then something went wrong with the auto shifter. It would only go into neutral and drive. The car would start in neutral but if I tried to start it in drive, It showed the same problem as I originally posted - no start and the dash lights would go out for a few seconds. The shifter was replaced and we have now gone for almost a year with no problems. I suspect the problem was some switch in the shifter that was malfunctioning.

No crank.
 

My car is apart ( shifter boot and top off because I replaced a shifter cable). The cable was broke at the end by the shifter). When this problem happens I checked the micro switches at the shifter for resistance (not the problem). If the connections at the fuse box were loose (already checked) it would not shut power off and back on in the same amount of time every time. I think this is computer related because too many people have had the same problem and different years. My car has done it three times. I am working on it and will try to fine a common item or sequence that it starts from.

ARGH!!! You both have/had good battery - power goes off for a fixed amount of time - power returns. That is a bad cable connection. The power is going off when the starter motor is engaged and tries to draw several hundred amps through a faulty connection. The power comes back on when the BCM sees that the starter isn't doing what it was supposed to do and turns the starter motor off. OP, your issue was probably at the battery since a cable was disconnected and reconnected when the shift lever was worked on. Foley, your issue is more likely at the starter solenoid. A lot of people have reported loose connections at the starter solenoid which eventually will melt the connection if not cleaned and tightened.

Feel free to prove me wrong. :cheers:

Sometimes no crank
 

The starter has been out and another one installed (same problem). One thing I did was monitor the voltage going to starter selonoid line and when this happens and there is no start voltage to the selonoid. Next I tried and hooded up a wire from the selonoid wire and when it happed I put 12 volts to it and vehicle cranked over fine. I ran into a person today with a very nice 22,000 mile 2006 today and asked him if this every happened to him and he replied yes a couple of times, said he took to dealer and could not duplicate been fine for months. Since it always comes back on at same time frame I still think it is computer related problem. I am open to anything. Just don't want wife to get stuck in this vehicle.

This is a little long winded but I worked through the issue and I think I have an answer (OK, maybe I was wrong. Happy? :D )



There are a lot of things that will cause the starter not to crank. The clue here is that the lights go out at the same time. The only thing that will cause the lights to go out is that the battery is no longer able to supply power to the lights. Your idea that the battery rundown protection circuit is the culprit would make sense except that circuit does not control the dash lights nor would the BCM have programming that says to bypass the 20 minute delay if the starter button is pushed.

So what could cause the battery to act like it was disconnected from the rest of the car when the starter button is pushed. Weak battery is first but that was eliminated. That leaves the connections from the battery to fuse box and to the starter solenoid and the battery negative to the frame. Pull too much current and the resistance of a connection will make it seem as if the connection is open. As you can see, there isn't much else.
Attachment 48144577
When you say you jumped power to the starter solenoid (dangerous on a car with computers but OK in this case because there is a physical crank relay) and the engine cranked normally that means several things. Either the crank relay is not being given a control voltage to do the same thing or it isn't closing and secondly that the issue isn't the starter motor pulling too much current for the connection resistance. But where does that leave us? If the starter motor works and the lights don't go off then that is a major load on the battery with no issue. :crazy2:

So after looking through all the schematics and diagnostic procedures and coming up with nothing I went out to my car and started it. Are you aware that it is normal for the dash lights go out while the starter is cranking? I honestly never noticed that before. The car always starts quickly so the lights only go out for a moment. But they do go out except for the CEL. That has to be the BCM turning them off while telling the ECM to close the crank relay. If the crank relay doesn't pick up for some reason, the engine won't crank and the BCM will time out and turn the lights back on as it stops telling the ECM to crank.

So now I'm thinking the issue is with the crank relay or the ECM. I still have a problem with the OP saying it was an issue in the transmission since any safety permit not being met (transmission/clutch/brake switches) would prevent the BCM from issuing the crank request but should also stop the turning off of the lights. Do they go off normally when a permit isn't made? I don't know and don't want to go out to the garage again at the moment to check.

I have the diagnostic procedures for a no crank condition and will be glad to send them to you. It's a rather long procedure with 23 steps (3 pages) but you skip many steps based on the answers. It also requires the scan tool but you can usually figure a way to test without it. You can at least eliminate all the parts in the above schematic. PM me if you want me to email you the pages. Basically you need to test around the crank relay next. Just be aware that the coil of the crank relay is connected to a computer and you shouldn't start jumping voltages into computer terminals without knowing what is going to happen.

Thanks for the imput. I do notice that CEL stays on as do the interior lights (they do not dim) but dash lights do go out and come back on at always the same time frame. The vehicle is at the shop and will get back there on Thursday & Friday. I have the no crank check list and when I started to troubleshoot it was fine for a couple of days. I have a friend that is a master tech at GM and said Corvette's have come in with same problem described but never seem to act up at the shop. Thanks for all the help.