'02 Impala 3.4l, 97K: Sudden No Start

Started fine, drove fine 15 minute ride 1st thing in the morning. Sat for about 7 hours. Started fine again, drove fine 15 more minutes. Turned off then wouldn't restart. Nothing - according to person driving at the time. No click, no nothing. I arrived less than 30 minutes later, car started right up. I then drove the car 25 more miles without any problems.

Car has simple key - not computerized. Also has 6 month old battery (but that couldn't be the problem). Any ideas. I will be checking for any computer codes in the meantime (driver claimed Check Engine light was ON when car wouldn't start, but I think this is a normal thing. Light was not ON when I drove the car).

Was the security lite staying on during this event? the car has passkey 111 which could cause this as well as poor battery connections, just to name 2 possibilities.

Not the battery - 6 months old and very clean. But it could be Passlock - forgot about that. Driver did not report any SECURITY message, but the LOW COOLANT LEVEL message is currently dominating this display (another problem that I'm well aware of), so it's possible it DID appear but was then masked by the LCL message.

Passlock makes sense. I'll have to look more closely at that. Any way to get rid of Passlock???

The BCM is involved in the system as well as a security module I am sure there is someway.

BCM. I'll consider that too. No problems since. I DID see SECURITY show up in the message center when starting the car (ON position), but otherwise everything seems normal.

I see another thread that talks about disabling Passlock. Thanks.