It got me thinking after a couple of car services just the other day. Take for instance, a 2011 Mercedes ML350 that rolled into my shop showing brake light malfunctions and a “brake light failure” warning on the dash. Our initial hunch pointed towards a faulty rear SAM module. Replacing it, a part costing around $400, seemed like the fix.
However, as it turned out, our first diagnosis was off the mark. The Mercedes didn’t need the expensive module at all. The real culprit was a mere $16.50 wiring harness. I was upfront with the customer about our misdiagnosis. I let him know he wouldn’t be charged for the module we had installed in error, and to his credit, he was quite understanding.
Then there was a 2002 Honda Accord that wouldn’t shift into reverse. A transmission shop sent it our way after a complete transmission rebuild. The issue? The car still refused to reverse. They’d even consulted a Technical Service Bulletin (TSB) suggesting a software reflash could solve it.
In this scenario, the customer could have ended up paying for a whole new transmission based on an incorrect initial assessment, when perhaps only a software update was needed. However, upon investigation, we discovered the software was actually current. The problem was traced back to a defect in the transmission rebuild itself. The transmission shop had to rectify their repair.
These experiences make you wonder about the broader picture in auto repair. Are most shops quick to admit diagnostic errors like mine, or is it more common to hear justifications like “it probably needed replacing anyway” or “it was on its way out”?
In the competitive world of auto repair, where customers are often wary of diagnostic fees and some shops resort to guesswork and parts swapping, it seems almost inevitable that diagnostic mistakes will occur. One could argue that customers who undervalue professional technicians inadvertently contribute to this environment, as even medical doctors aren’t penalized for every misdiagnosis.
What are your thoughts on navigating the complexities of car service and the occasional wrong diagnosis?
