Why does a vehicle with an illuminated check engine light return to your shop, seemingly long after technicians touched it?
Completed monitors may have detected and flagged an improper repair on the vehicle's engine management system.
Technically, failing to fix the system correctly caused the comeback. The monitor, however, confirmed the mistake long after the vehicle left the bay.
Monitors are nothing more than self-tests that an engine management computer (ECM) routinely performs on components and circuits it controls.
I grossly simplified monitor basics in my last column. Here I will recap and expand that discussion to explain why some comebacks take a long time to come back.
Understandably, comebacks are as welcome as a bad check. Sometimes, the ensuing frustration blinds owners, managers and service sales personnel to several possible causes.
For example, an entirely fresh problem may have cropped up — something wholly unrelated to the repairs the techs already performed on the vehicle.
Savvy service managers coach techs to look for legitimate repair opportunities on every vehicle, but even a capable, conscientious tech may overlook an imminent failure during a vehicle inspection.
When the breakdown finally occurs, a disappointed motorist returns to your tire dealership or service shop seeking answers.
Please keep a reasonable perspective on automotive breakdowns. For example, I noted a June column that the average age of light vehicles has reached 12.2 years.
In my view, an average age greater than 12 years old is a significant statistic.
The older a vehicle is, the more realistic it is to find multiple problems on it instead of a single one. Furthermore, the potential for numerous problems per car means techs should check each vehicle as thoroughly as practically possible.