Park Assist Off/Doors Lock/Engine Lagsv

[ScienceMonkey]

My 2008 Avalanche (29,000 miles, garaged) started having the problem sporadically about a month ago.

 

While driving, the Park Assist Off message would flash on the dash, the doors would lock, and the engine would lose some power. When the truck was not in motion, the engine would stall.

 

Two separate dealers could not find any problems (but it still cost me $200).

 

I replaced the 175 amp mega and the problem has not reoccurred.

 

I've taken some good advice from these forums over the years, but couldn't find any reports of the same issue. I felt I owed it to the forums to create an account and post. So, thanks to all of the posters who have helped me with my previous problems.

[ScienceMonkey]

Spoke too soon!

 

The problem didn't recur for 70 miles.

 

The Park Assist Off message flashes on the dash, the doors lock, the engine didn't seem to lose some power this time, but there's a new twist. The low fuel warnings kicked on (dash light and NAV) and the physical gauge went to empty. After another ten minutes of driving, the fuel gauge slowly moved back to an accurate reading.

 

I am stumped and so are the dealers. Any clues?

[ScienceMonkey]

I received additional help under a similar topic. Here's the solution that has been working (so far):

 

I tracked every visible and reachable wire in electrical system from back to front looking for any damaged or loose wiring. That took over an hour and everything looked fine.

I unbolted the ground wire from behind the driver's side front wheel (10mm), cleaned and degreased both the wire and the frame, lightly sanded the frame around the post to ensure good contact, and tightly re-attached the wire. I had previously replaced the 175a mega and still had one recurrence.

I have driven almost 300 miles now and have not had any recurrences of the problem. If I have any more issues I'll update, but at this point I'll say the issue has been resolved.

​

[anumber1]

I received additional help under a similar topic. Here's the solution that has been working (so far):

 

I tracked every visible and reachable wire in electrical system from back to front looking for any damaged or loose wiring. That took over an hour and everything looked fine.

I unbolted the ground wire from behind the driver's side front wheel (10mm), cleaned and degreased both the wire and the frame, lightly sanded the frame around the post to ensure good contact, and tightly re-attached the wire. I had previously replaced the 175a mega and still had one recurrence.

I have driven almost 300 miles now and have not had any recurrences of the problem. If I have any more issues I'll update, but at this point I'll say the issue has been resolved.

​

Of the few "modern" GM cars I work on, communication issues with the various control systems are the new trouble spots.

 

First step stuff nowadays is checking basic wiring integrity, like grounds and even battery condition.

 

I had a recent electronic ps rack code that turned out to be a simple weak battery...

[ScienceMonkey]

SOLVED

 

I did start an additional thread this spring as the problem started happening again, so I want the solution posted here too.

 

The issue ONLY happened when the outside temperature was above 70 degrees. My repair attempts last fall fooled me into thinking the issue had been resolved, but it was just autumn temperatures. A local pro worked with it on and off for a couple of weeks and had the same experience with zero incidents below 70 degrees and incidents every few minutes when the temperature was above 80 degrees.

 

He had the ECM replaced (still under warranty) and the issue has not occurred once, even in 80+ degree weather.