My 1999 GMC Sierra has the check engine light on, ABS light on, the Brake light on and when I took it to emissions, it failed to communicate at all with my truck when they plugged it in. Any help?
Check your cigarette lighter fuse ( under the hood on the driver's side marked cigar) if that is burned out the communication port won't work. Clean all the ground wire connections (there are several) you can find along the frame rails and that might fix the ABS light problem. Also clean all of the ABS connectors with electrical cleaner and use electrical grease on them. Don't forget the ground wire at the battery, engine, and firewall. These are the "Cheap Checks" after that then your looking at wheel modules or EBCM replacement/rebuild (absfixer.com). Good Luck
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