[jman032]

I just bought an 08 impala SS that wouldn't crank. It also has the following issues, which the previous owner said all occurred at once:
1. Car doesn't come out of park without pressing in the button underneath the shifter cover
2. Key doesn't come out of ignition unless you press the button on the bottom of the ignition switch.
3. Gear selection screen doesn't show the current gear, using a scan tool shows that the car thinks its in 3rd gear.
4. Windows, door locks, steering wheel controls, and dome light do not work
5. Blinkers, hazards, and high beams do not work (regular headlights do)

I've done some diagnostics and established that I have good power and ground to the BCM including ignition voltage. I also have ~60 ohms resistance between the high and low CAN wires on the OBDII connector with all modules plugged in and the battery disconnected, and 120 ohms with any/all of the modules unplugged.
I'm really having trouble finding information on how to diagnose this issue. I'm unable to find pinouts for this car's TCM connector to check its voltage properly, but it does have 12v at the pink wire and ground at the black wire.
I believe I have a bad BCM. The scan tool says there's no communication with the BCM when I try to look at it's data display, but I'm not sure what I can do to further diagnose this.
The previous owner said all this happened after the battery died one time and he put a new battery in it. I'm thinking maybe he got the wires crossed and shorted the BCM or one of the other computers? I did get the car to crank by tripping the starter relay but have no fuel or fire.

Any help or feedback is greatly appreciated!

 

[jayoldschool]

Head on over to impalaforums.com for help with your FWD Impala

 

[jman032]

Head on over to impalaforums.com for help with your FWD Impala

Done, thanks for the direction!

 

[Boxer 95ss]

I just bought an 08 impala SS that wouldn't crank. It also has the following issues, which the previous owner said all occurred at once:
1. Car doesn't come out of park without pressing in the button underneath the shifter cover
2. Key doesn't come out of ignition unless you press the button on the bottom of the ignition switch.
3. Gear selection screen doesn't show the current gear, using a scan tool shows that the car thinks its in 3rd gear.
4. Windows, door locks, steering wheel controls, and dome light do not work
5. Blinkers, hazards, and high beams do not work (regular headlights do)

I've done some diagnostics and established that I have good power and ground to the BCM including ignition voltage. I also have ~60 ohms resistance between the high and low CAN wires on the OBDII connector with all modules plugged in and the battery disconnected, and 120 ohms with any/all of the modules unplugged.
I'm really having trouble finding information on how to diagnose this issue. I'm unable to find pinouts for this car's TCM connector to check its voltage properly, but it does have 12v at the pink wire and ground at the black wire.
I believe I have a bad BCM. The scan tool says there's no communication with the BCM when I try to look at it's data display, but I'm not sure what I can do to further diagnose this.
The previous owner said all this happened after the battery died one time and he put a new battery in it. I'm thinking maybe he got the wires crossed and shorted the BCM or one of the other computers? I did get the car to crank by tripping the starter relay but have no fuel or fire.

Any help or feedback is greatly appreciated!

Well the first thing I would check is the key to see if it has the chip and to see if it's got the right ohms cuz if the kids getting stuck it's fine at the right key for the ignition just by force in there so it's probably not the right key for the I don't know if that one has a chip on it or not but mine did so I had to bypass the security and I'm just throwing this out there if the coolant temperature sensors are unplugged the car won't start if there's certain sensors of any of them are unplugged or ain't getting current it won't start that happened to me already

 

[jman032]

Well the first thing I would check is the key to see if it has the chip and to see if it's got the right ohms cuz if the kids getting stuck it's fine at the right key for the ignition just by force in there so it's probably not the right key for the I don't know if that one has a chip on it or not but mine did so I had to bypass the security and I'm just throwing this out there if the coolant temperature sensors are unplugged the car won't start if there's certain sensors of any of them are unplugged or ain't getting current it won't start that happened to me already

I actually hadn't checked the TCM for codes and when I checked it, it had a code for no communication with the BCM. I double checked power and ground at the BCM and went ahead and ordered a new module (comes programmed to my vin). It should be here today so we'll see if this fixes it. If not I'll check the security system.
As far as sensors go, I can see that they're all communicating with the PCM, so I don't think that any of them are unplugged.

Also, my friend works as a fleet mechanic and said that when they still had impalas there was a service bulletin for their BCMs going bad and they ended up having to replace 4 or 5 of them .

 

[pntcfh2011]

My wife's 2008 SS had a similiar issue. Not as bad but there is a module next to the shifter that allows the key to be removed. Her's oddly went bad when I left the ignition on at work and killed the battery. I wired the purple and white wire together to bypass and hasn't been a problem since. Still never replaced the module.

 

[jman032]

My wife's 2008 SS had a similiar issue. Not as bad but there is a module next to the shifter that allows the key to be removed. Her's oddly went bad when I left the ignition on at work and killed the battery. I wired the purple and white wire together to bypass and hasn't been a problem since. Still never replaced the module.

Thanks for the response, but I just fixed it today.
It was a BCM. I got the new one last night, plugged it in, and the car fired right up.
Really appreciate you guys responding!