put the car on a battery tender , went to start it after a couple weeks and the guages all come on but its dead when I turn the car to start , disconnected the battery reconnected battery and it started, left the car for 15 minutes and its dead again did the battery disconnect and reconnect and it starts fine no problems til I let it sit 15 minutes or more and we are back to the same problem. any ideas Thanks
help car wont start
- Thread starter katreg
- Start date
when you say it's dead does that mean it doesn't even crank over or it just does not fire?
- Thread starter
- #3
Doesn’t crank over
This sounds too simple but it really sounds like a bad/dirty/loose battery post connection or ground connection.
- Thread starter
- #5
I was hoping it was something that easy
but unfortunately connections have all been checked and they are all good , going to start looking at the security system
Dave91TM
Power User
I had a slew of no start issues, but it was always intermittent, not consistent as your seems to be. One clue might be , when you try to start, just turn the key on and listen for the fuel pump. The security system shuts down both the pump and the starter. if you get no pump and no starter, then ,maybe, the security system.
Otherwise may be a wonky relay . Look for something simple and keep digging. Good luck.
Otherwise may be a wonky relay . Look for something simple and keep digging. Good luck.
That sound to me like a VATS issue. The anti-theft system on the C5 is designed to prevent the car from cranking if it doesn't detect the proper resistance on the key. If you look at your your key, you will notice a small silver stripe that is enclosed within a black oval. This is infact a basic resistor. When inserted, the car will determine if the resistance is correct, and allow the starter and fuel pumps to become energized.
Many times, these surfaces can become slightly oxidized and skew the resistance value enough that the vehicle will no longer start. I would clean the key surfaces with rubbing alcohol, and then try again. You can also use a multimeter (ohm meter) to read the value of the key to ensure it at least producing some sort of resistance. I have seen the resistor in a key fail entirely before.
Hope that helps..........
Many times, these surfaces can become slightly oxidized and skew the resistance value enough that the vehicle will no longer start. I would clean the key surfaces with rubbing alcohol, and then try again. You can also use a multimeter (ohm meter) to read the value of the key to ensure it at least producing some sort of resistance. I have seen the resistor in a key fail entirely before.
Hope that helps..........
- Thread starter
- #9
thanks I m going to look into that, the resistance was 1.4 and i do notice that the fuel pimp does run when i turn the ignition to on. this all worked fine til I hooked up the battery tender because the battery would go dead after sitting for more than a weekThat sound to me like a VATS issue. The anti-theft system on the C5 is designed to prevent the car from cranking if it doesn't detect the proper resistance on the key. If you look at your your key, you will notice a small silver stripe that is enclosed within a black oval. This is infact a basic resistor. When inserted, the car will determine if the resistance is correct, and allow the starter and fuel pumps to become energized.
Many times, these surfaces can become slightly oxidized and skew the resistance value enough that the vehicle will no longer start. I would clean the key surfaces with rubbing alcohol, and then try again. You can also use a multimeter (ohm meter) to read the value of the key to ensure it at least producing some sort of resistance. I have seen the resistor in a key fail entirely before.
Hope that helps..........
- Thread starter
- #10
Thanks I will check that . like I said as soon as I reconnect the battery its all good for 15 minutes then its dead again til I disconnect and reconnect the battery then we are good for another 15 minutes.
Dave91TM
Power User
from what you are saying, it appears that the battery may be shot. When I was getting mine out of storage this year, my battery minder showed the battery as satisfactory. When I hit the ignition, I got nothing. New battery fixed it.
I agree. "this all worked fine til I hooked up the battery tender because the battery would go dead after sitting for more than a week " doesn't sound right.
Battery
- Thread starter
- #14
battery is brand new this year
Some batteries are bad even if new.
Doesn't the C5 have a column lock? If so, the module could be going bad, but should be getting a column lock alarm.
The 2005 C6 has the column lock issue, and there is a TSB for a permanent fix.
Whenever the column lock module fails, disconnecting the battery will reset the column lock and the car will start.
Good Luck
The 2005 C6 has the column lock issue, and there is a TSB for a permanent fix.
Whenever the column lock module fails, disconnecting the battery will reset the column lock and the car will start.
Good Luck
- Thread starter
- #17
Thanks hadnt thought of that angle
How many times was the new battery allowed to go dead and how long did it sit dead between charges? Big factors that can tank even a new battery fast. Have you load tested the battery after a full charge?
- Thread starter
- #19
CThat sound to me like a VATS issue. The anti-theft system on the C5 is designed to prevent the car from cranking if it doesn't detect the proper resistance on the key. If you look at your your key, you will notice a small silver stripe that is enclosed within a black oval. This is infact a basic resistor. When inserted, the car will determine if the resistance is correct, and allow the starter and fuel pumps to become energized.
Many times, these surfaces can become slightly oxidized and skew the resistance value enough that the vehicle will no longer start. I would clean the key surfaces with rubbing alcohol, and then try again. You can also use a multimeter (ohm meter) to read the value of the key to ensure it at least producing some sort of resistance. I have seen the resistor in a key fail entirely before.
Hope that helps..........
- Thread starter
- #20
Car has had the lmc5 installed so the column lock has been bypassed and I’ve done the brown wire upgrade also