2004 saturn vue - 96K miles. Kids car. this has happened 3 times now.
in driveway all dash lights started flcikering, car shut off, key stuck in ignition. i unplugged ECM and plugged back in. car worked fine
happened a 2nd time maybe 2 month later in taco bell drive thru. i did same thing car worked after that.

i took it to local shop and they founf that the main ground on the back of the engine wasnt even hooked up and that the ECM was directly grounded to the negative terminal of the battery. they fixed it and said this should solve it.

it happened again last night in the drive way. here are the codes:
p069e - fuel pump control module request MIL
p0700 - Trans axle control module
p2101 - throttle position actuator
p1516 - throttle actuator control
u0073 - BCM - no solid connection

all of these are directly linked to the ECM. i suspect either I have multiple ground issues, or the ECM is going bad.
can i get your thoughts please?

the wiring harness that goes into the ECM clips look like crap. i wonder too, if moisture may be getting in there?

also, the kids have had this car for 12 months with no issues - the past 4 months have yielded these elctrical woes. the only change done to the car, was a new after market radio - installed "professionally" (abc warehouse) - could they have boogered something up??

PLEASE HELP

 

BCM connection issue worries me the most. However that may be as a result of the ECM connections being a mess.

I'm taking it this is a used vehicle and that things like an unconnected main ground as you stated are the result of a previous owner taking desperate measures trying to deal with some sort of electrical issue.

Remember that the body control module controls essentially everything besides the engine. That is what the ECM does.

2008 fuel has a transponder in the key as part of the security system.

Radio installers are always looking for the quickest way to do an install. Rather than running new 12 volt lines from runs in the fuse box, they piggyback the closest runs they can find which usually involve piggybacking off of wiring near the ignition to get the always-on 12 volts and the 12 volts to light the display at night.
Depending on what those 12 volt lines are feeding, it could conceivably mess up the security system as that has been beaten to death in other questions on this and other forums.

I believe that version of the security system is intermittently running a check to see if a transponder is still in the ignition. If not, it assumes it is stolen and shuts the vehicle down.

I am falling asleep writing this and most likely will add more later

 

correct - preowned. when the shop noticed the other issues, they also noticed that there was numbers in yellow on the engine. they wonder if the engine was replaced. not sure on that.

look forward to more advice

 

Likely. Sourced from a salvage yard.
likely "known running" coming in from a wreck. Don't know the schematics on that puppy. Maybe whoever put that engine in as a swap was slightly under qualified to do so.

Can you provide pictures of the negative battery lead running to wherever it is grounded and the path of the positive battery terminal wire, wherever that leads to other than the alternator. Meaning under hood junction box, ECM? And who knows what else. With today's cars so heavily dependent on proper electrical connections and functional circuitry, there is a premium to be put on having the wiring that supplies the entire vehicle with power hooked up cleanly and correctly. Especially without knowing the history of this vehicle.

Is there per chance any significant rear end damage history or visible signs underneath to the vehicle?

 

the car is currently at a local, trusted, shop for further diagnosis. I will take pics upon getting it back.
there is no evidence of any collision in front or back.

when i drove it to the shop, it drove perfect. CEL was still on - so the codes are present for them to scan. i'll keep you posted on results