My daughters car started giving a warning of Service Steering. The gauges went to all zero. I scanned the codes and it was ECM[img]data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7[/img]0089, ECM[img]data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7[/img]0700 and TCM:U0073.

She broke down close to a GMC dealer so we replaced the Red Battery cable and fuse distribution block on the battery.
It seemed to work for the ride home. Then started again a day later. This set off a new set of codes ECM[img]data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7[/img]0700, ECM:U0101 and TCM:U0073. I ordered the replacement negative cable. Ordered the new short red cable to the block. THis was the one everyone is using to solve the issue. Removed all ECM and TCM connectors and sprayed with electronic cleaner and blew out with air. Cleaned the 3 ground points in front of the battery.

The car drove fine for several days. Did it again today and she is stranded. Had her try clearing the codes so it would shift properly. Check engine light keeps coming right back and car wont move well without a lot of throttle.

Battery is 4 months old and Autozone tested it as good. Alternator is about 1 year old.

At a loss what to try next. Grease all the wire harness connectors?

 

They had a lot of problems with the ign switches and it would be worth a good careful check to make sure it is not malfunctioning causing loss of power to a lot of components..