I occasionally do work for a used car dealer or two. One in particular specializes in hybrid and electric cars. A couple of weeks ago he dropped off a 2008 Prius with a check engine light on. He told me it had a code P0456 which is a code that is related to the system that monitors if the fuel cap is on tight or not. The system can also tell if there are any other fuel vapor leaks in what is known as the “evaporative emissions system” He said he had already replaced the gas cap and the light kept coming back on. That was all the information I got from him at the time.
The code (P0456) is defined as a “very small” fuel vapor leak. It does not tell me where the leak is. That’s the tricky part sometimes. One of the tools we use to test this system is called a smoke machine. Surprisingly, it is a machine that produces smoke. We connect it to the pluming of the EVAP system, turn it on, and, hopefully, find where the smoke is leaking out. This is rarely as easy as we’d like it to be but on this car I got lucky and detected a very small bit of smoke leaking from a rubber hose under the hood. I replaced the hose, retested the system and all was good. I called the used car lot and told the owner it was good to go. $135.00 please.
This is were the story gets interesting. When the owner picked up the Prius he told me he had purchased the car from a local Toyota Dealer’s used car lot. The used car manager had told him that this particular Prius had been traded in, in frustration, after the previous owners had paid a good deal of money on three different visits to the dealer to have the check engine light problem fixed. On the final attempt, the service department presented them with a bill for the work that had been done, yet the car was still not fixed. The owner was understandably upset and refused to pay yet another bill for the same problem that he had already paid to have fixed twice before. The Toyota dealer’s solution to this mess was to have the new car department offer to pay the service departments bill if the owner of the Prius would trade in the car for a new one. This is exactly what they did. All because the service department supposedly could not fix a car, on three attempts, that I had diagnosed, and repaired successfully in one hour.
I’m not a magician. Nor am I the greatest diagnostician around so I cannot imagine how a Toyota dealership which in theory should have at least one master technician on its staff could have missed such a simple problem.