Hello and welcome to Just answer.com, Super mechanic here. About your vehicle.
It may be a good idea to have the charging system checked just to be sure, (that can be done at an Autozone store, if conveinient) however, sometimes when the battery voltage gets low, (possibly from leaving the key on at the shop) the gauge will read a little lower.
Here is some of what the service bulletin says about it.
Any vehicle may have a low voltage display (if equipped with gauges), lights that dim at stop lights, slow cranking, no start, low generator output at idle or dim lights at idle when electrical loads are heavy at idle or under slow driving or infrequent usage conditions. These characteristics may be more noticeable with customer added electrical accessories, or with a discharged battery. These are normal operating characteristics of a vehicle electrical system and no repairs should be attempted unless a proven fault has been diagnosed.
Also, will want to be sure that the battery is good and passes a load test as well.
Auto Mechanic
ASE master, 30+ years. All makes and models. Trouble shooter, shop forman, service manager