An ounce of prevention is worth a pound of cure. This old adage aptly sums up a sensible approach to disconnecting batteries from unfamiliar vehicles.
My columns in recent issues of Tire Business (March 4, March 18) describe the potential perils of disconnecting a battery from a vehicle without providing auxiliary power to it beforehand.
A battery disconnect may erase some of the memory inside on-board computers temporarily, causing strange symptoms after a technician reconnects the battery to the vehicle.
In my March 18 column, I described a technique for providing auxiliary power to a vehicle prior to disconnecting its battery for any reason.
Some readers have responded to these topics with interesting questions.
First, a fellow asked about the consequences of disconnecting the battery on a 1993 Cadillac that he stored for the winter. An educated guess on my part — a hunch — is that disconnecting the battery on a relatively simple 1993 vehicle shouldn't cause much trouble.
Of course, he would have to reset the car's digital clock. Thereafter, this car probably would perform fine after he drove it for a short time.
However, I'm reluctant to make hard, fast judgments — especially on unfamiliar vehicles. Battery disconnect has fooled me.
For example, I'm doing homework on a car at a service shop or tire dealership. A task requires disconnecting the battery; I gamble that a simplistic-looking vehicle won't suffer if I disconnect its battery without attaching auxiliary power to it first.
But after I reconnect the car's battery, the automatic transmission shifts late and harshly.
Then it takes 30 minutes of road testing to normalize the transmission again. This extended road testing enables the car's transmission computer to "re-learn" its normal values for shift timing and shift quality.
Recently, I saw a flummoxed customer return to a shop with a 2017 Subaru WRX.