The first on-board diagnostic (OBD) computers trace back to the late 1960s. Today, diagnostic scanning devices have become more sophisticated and less expensive.What sort of diagnostic capability makes sense for the average installing professional’s fleet?Gerry St. John, of Alpha-Bid.com operates an online business selling engine diagnostic equipment.“Whether you call them scanners, code readers, scan tools or OBD devices, they amount to the same thing,” he says. “They read the error codes from the computer in your engine.”The most basic and inexpensive scanners will read codes and erase some of them.“These are often all you need if you want to do
