Ground wire problem???
Thread Starter
Burning Brakes
Joined: Oct 2013
Posts: 859
Likes: 1
Ground wire problem???
Today my engine straight up shut off while driving on the highway. Lost communication with PCM, and service vehicle soon, check tire pressure, service active handling, along with every other check this and that popped up on the DIC. Fuel gauge read empty (had full tank). Car would turn over but not start, all interior instruments/lights worked however. I got out and shook the cables leading down to the starter (thick red and black ones) from the battery and it regained communication and all service lights disappeared, fuel gauge read full, etc. She fired right up. So, wtf lol. All connections on starter are tight. Battery cable connections are tight. I'm guessing ground wire problem, what do you guys think?
Thread Starter
Burning Brakes
Joined: Oct 2013
Posts: 859
Likes: 1
I should also add that there was relay chatter in the fuse box in the ignition relay. After I shook the cables leading to the starter, this sound stopped and the car regained communication and fired right up. Where is the ground that may be affecting this? Still new to the C5!
Thread Starter
Burning Brakes
Joined: Oct 2013
Posts: 859
Likes: 1
Had battery tested this morning, good to go. Sure enough, on the way to the auto store it happened again (car died, loss of communication, etc.). Shook the cables, good to go. How annoying. Alternator is working well, battery is holding charge. I'm assuming that the cable wiggle is causing something to re-connect causing me to be able to start again. That's why I figured it was a ground. Looks like I'll be cleaning them this evening.
Le Mans Master
Joined: Mar 2011
Posts: 6,835
Likes: 302
From: Columbia SC
I helped one person a while back with a similar issue. When he closely examined the connections at the starter and the cable coming into the connection lug was loose. He put a new lug on it and made sure the crimp was sound and it fixed his problem.
Thread Starter
Burning Brakes
Joined: Oct 2013
Posts: 859
Likes: 1
Just updating as reference for those that may be having similar issues. PROBLEM SOLVED!!! Turns out the ground wire connection on the engine block on the passenger side was extremely loose. Every time my engine shut off and I shook the cables leading down to this area it would slightly connect (until it shut off again). A big thanks to those of you who posted helpful info. I checked the door accordions and several other places before I began with the grounds. Moral of the story, start with the simple stuff first like grounds then work your way to the harder things 
