Electrical Gremlin
Thread Starter
Advanced
Joined: Feb 2019
Posts: 69
Likes: 10
Electrical Gremlin
This morning on my way into work my I tried roll up my windows but no success. I noticed there was no power to the DS door so none of the controls were working. The PS door was active and I was able to roll up the PS window. About 20 min into my trip the DIC flashed a warning saying reduced power and the red check gauges and security lights flashed on. About 30 seconds later a few gauges in the cluster (Oil pressure, Temp, fuel level) all swept and stayed at the minimum value. The gauges came back online and the red check gauge went off but the security light stayed on. This happened twice in a 30min commute. When I arrived at the office I shut the car off, counted to 20 and restarted. Everything including the DS door controls came back online. where do I start??
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,642
Likes: 4,082
From: Cape Coral, Florida
Sounds like the "classic" serial data bus issue. The serial data bus is how the cars modules (BCM,PCM,IPC etc) communicate between each other. What happens is power or ground gets on the serial data line and what you'll see is the fuel gauge goes to E and the water temp gauge will max out and almost all of this DIC messages...low fuel, reduced engine power...I never finished my YouTube video on how to diagnose this but maybe this will help.You can open the drivers door and in the "accordion" boot there is a connector for the drivers door module and you can check that the connectors there are clean and tight. I fortunately have a can bus tester and a scope and it makes for a quick diag. If the issue happens when starting the car it will be a start and stall. There are 2 "star connectors" (pictured in video) or Splice Packs and if you have this issue happening when starting the car remove the bus bars from the top of the connector with the fewer wires and see if the car starts...and make I would take some emery cloth and clean them till sparkling !!...If you have a voltmeter you can probe each of the wires on both star connectors and see if you see 12 volts on any one...a good data bus produces a 0-7 volt square wave...you will ONLY see this with a scope...with a good signal you will see only a volt or so or less with a voltmeter...I've included a video below !!
Last edited by C5 Diag; Nov 6, 2019 at 08:21 PM.
