Does a computer module retain a history of previous alerts?

  • 1 POST
  • 84,500 MILES

After buying a 2001 Camry and driving it three days locally, the engine light came on. It is a catalytic converter problem. Is there any way that the computer module retains a history of previous alerts so that I have some leverage with the Toyota dealer who is claiming they are surprised at the reading? It was driven from NJ to be put up for sale on their lot. Certainly seems like the light would have come on during that 900 mile trip.

Do you
have the same problem?
Sunday, September 4th, 2011 AT 1:25 PM

1 Reply

  • 29,768 POSTS

And it surely would have come on before driving it for three days. If the car was bought at a dealer-only auction, it could have been delivered on a trailer or car hauler. No one knows for sure what they're getting at those auctions because problems don't normally have to be disclosed. It's up to the dealer to inspect the cars before and after they buy them, and fix any problems, ... If they're aware of them.

At 84,000 miles, it isn't real likely the converter is defective, although it is possible. What was the diagnostic fault code? There are codes that indicate the converter has lost its efficiency, and there are codes that simply mean one of the oxygen sensors isn't reporting its findings properly. Sensors can fail anytime. If the Check Engine light had come on when the dealer had the car, it is very unlikely they would purposely ignore it and try to pass it off on you. They know if they simply reset it and erased the code, it's going to come on again and you're not going to be happy. What they DON'T have control over is when things like that happen after they sell the car. You can't hold them responsible for every unforeseen problem afterward.

To answer your question about fault codes, I can share the description I got at a Chrysler school. The diagnostic fault codes we can read with their DRB2 or DRB3 scanners are erased with those scanners or when the battery cable is disconnected, or after starting the engine 50 times after the problem no longer exists. After that, if we try to read any codes, we'll get the message "no codes". We were told there still is a permanent record of every code ever set, but it's retained in a different part of the memory that only Chrysler can access. If the computer is sent to them, they can reconcile every code and the mileage it was set at with every warranty claim, and prove or disprove the repairs and claims were legitimate. That is useful too when investigating claims of excessive emissions that don't meet government regulations, not for that one car, but for an entire model line.

That ability to retrieve previous codes goes back at least to the early '90s and probably even further back. Most manufacturers use the same strategies in their computer's operating systems, so it's fairly safe to suggest Toyota can do the same thing. You would have to remove your Engine Computer, send it to Toyota, assuming they would even be willing to investigate the matter for an individual who's hoping to cause trouble for one of their dealers, and if they did, they would probably charge you way more than the cost of the repairs you're trying to avoid. And if they found the Check Engine light had indeed come on previously, you'd still have to disprove the dealer's claim that they thought they fixed the problem, then reset the light. By your own admission, the light didn't come on for three days. The mechanic who did the safety inspection and any needed repairs and maintenance could have replaced or repaired something, thought it was solved, reset the light, and test drove the car. If the light didn't turn on again during that test drive, wouldn't he assume it was fixed? Whether or not the light was on previously is irrelevant because it will turn on in response to hundreds of different fault codes. You would have to know the previous code(s) which would have been erased, and the current code(s). If they're different, the car has a new problem. That can happen anytime and the dealer has no control over that. Some dealers will try to help you with repairs to make your buying experience a positive one, but there's a limit to how much they can spend on your behalf. In my area, it's common to offer a 30 day 50 / 50 warranty. That means you pay 50 percent of the cost of repairs. Essentially you're covering the cost of parts and the mechanic's time, and the dealer isn't making any profit and he's not losing any money. What he is losing is that mechanic's productivity from moving on to the next paying customer's car. The dealer is just breaking even. They can't do that for very long. Businesses don't stay in business if they just break even.

In the absence of that 50 / 50 written warranty, many dealers will still at least take a look at the car or give you a discount on the charge. If they flatly refuse to do anything to help you, you'll remember that the next time you're shopping for a car. The more reputable dealers survive on repeat business and word-of-mouth advertising. If they've been around a long time, you know they're taking care of their customers.

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Sunday, September 4th, 2011 AT 7:51 PM

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