Originally Posted by jschloss
After badgering the service department for some more information I was told that this exact type of error has occurred on other vehicles and even with different engines (Landcruiser V8 as one example, apparently owned by the owner of the dealership [Vann York Toyota]).
They call Southeast Toyota each time they see this problem and are told the same thing. Clear the CEL and change the oil. They have supposedly not seen any of the vehicles repeat the problem.
I'm left with the understanding that the service department/centers have absolutely no clue why these vehicles are throwing false errors. The people I spoke with kept throwing up nonsensical ideas as to things that could trigger it.
I was not charged anything for the visit and I have free maintenance for 2 years anyway. However, I can't say this does anything to build confidence in my new purchase.
After further review of the problem(s) I will recieve additional information in the mail, which I will in-turn post here on this thread.
Thanks for all the posts. I hope this helps anyone else who is seeing the same thing. I will probably make some calls to other local service departments to see if I can get any additional information as well.
jschloss, what I am going to type here is not in direct relation to your specific truck. I am going to try to give you some thoughts that may help you understand why we run into these types of things from time to time. It is not a Toyota issue (this specific example with your truck is) but more about how integrated vehicle systems are becoming.
Different features on our vehicles can use information and control capability from other systems to make them work. In the case of Auto LSD, it can be accomplished by using the brake system to control wheel slip. You can have a module that will take information from other modules on the system to help make control decisions about the system. As an example, the current engine rpm, torque output, throttle position and so forth could be important information. If the module that provides that data has detected a problem, it may not only illuminate its own telltale on the dash if the problem could cause an issue for another system. It may also broadcast a message on the network to inform other modules that the data is not trustworthy. The modules that need that data to work correctly will now also illuminate telltales to inform you that certain systems may not work correctly or are "offline" at this time. That is why something like a weak alternator can cause a multitude of systems to set off flags and they will all have a "code" for low power supply. That points you to where to start testing.
OK, so now there is a truck in the shop with a couple of lights on. We have a primary cause and a secondary effect. We check to current operation of the system and everything is currently operating normally. We clear the codes and operate the vehicle and cannot reproduce the problem. Now what do we do? The problem could be electrical, mechanical, electronic (programming) or even some combination. If you cannot duplicate the concern you are at a tough spot. Some of these "faults" can have VERY short detection windows in the computer. (a matter of seconds or even a fraction of a second depending on what we are talking about) So you put the vehicle back in service and see if it happens again. You track it, share the information with your peers and up the technical ladder. People try to find the conditions, common items between vehicles that show this condition or anything that would lead to a smaller window of cause for the next time you see the issue.
It sounds like the current thought (this is supposition here) is that there are some valve timing mechanisms that are a little tight on tolerance. If they have even a small delay in activation or release they can cause a very intermittent fault from time to time. The current thought may be that as they wear in, the chance of a "hang up" goes down and the fault does not occur again. It sounds like there is a pending TSB on the issue. Please share whatever information they give you as it may help make the picture a little clearer.
I hope this explanation helps with what a tech can be up against with modern vehicles. There are just so many combinations of events that can line up that duplicating them can be difficult.
For your part, paying attention to how, hot or cold the vehicle was, the weather conditions and so on can all be clues to the root cause of the problem.
No, I do not work for Toyota and I am not a fan-boy. Just hoping to help.