SO FRUSTRATING, these pesky lights. Its like a grab bag in reverse, "Am I going to have to spend hundreds or thousands?" Then again, sometimes its a simple gas cap. We understand your hesitation to bring that vehicle in with that light on, don't forget, we have cars too. Its never fun, but we can ease the pain and give you valuable information once we see what complaints the computer is having with the system. There can be literally thousands of different codes and possible reasons. On the other hand you may not bring it in because it still starts and runs fine. Well we've seen that a lot also, the problem there is as a result of one problem other things could have a domino effect. We have seen as many as 20 plus codes relating to 10 different systems, but the check engine light only comes on once. Don't let them stack up, we can guide you as to what are priorities and what may leave you stranded, while you budget for anything the pocket book doesn't allow at the time. Much easier to conquer the problem if you know what your dealing with. Then on the other hand, sometimes you attack the problem only to find out that there is another problem, OH MAN we sure don't like these. In my video I attempt to explain why and how this works, but Ill spend a few keystrokes here on that.
If a engine computer is only as smart as the sensors going to it then it can only make decisions based on that input... right?!! So, if one sensor fails in some way, and another sensor or actuator fails in the same system but is only designed to work based off of the first sensors input, well then you have an issue. So the Check engine or Service engine soon light comes on and there is only 1 code, we trace and run multiple test to verify the sensor, the wiring, the computer logic etc. We come up with definite reason to replace that sensor. But wait, you say, what about that actuator? EXACTLY, we have no reason to even investigate that actuator, the computer doesn't even run a test on it to indicate to us that there is a problem further downstream. so we replace the sensor and clear the codes , Yippee!!! No check engine light! Now we drive the vehicle and verify all working correctly. This is were it gets ugly, the next time the vehicle tests itself it sees the
sensor is good, so
it continues to run its own internal test further, but this actuator may not function except under very specific circumstances. So a day or week later , back comes on that nasty check engine light. Frustrating to say the least! The trouble code is pulled only to find that is not the code that popped up last time. Long story short, replace the next failed part, and never see that light again. There are several other circumstance that this repeat check engine problem can come back on after a repair. The biggest defense you have as a client of any shop is communication! Be sure your gut feels ok, and if it doesn't ask questions until you understand, don't be afraid to interrogate the person selling you parts and service, but also understand that no matter how competent a shop is this scenario has plagued the best of them.
Now there is one other way to avoid this. The computer has a strategic system to test ALL systems. We refer to it as Monitors. If they are not all "Completed", then the computer has not finished testing all the system. So, if ALL the Monitors ARE completed and there is NO check engine light on, well your are 98% sure that there are no more hidden issues currently. Unfortunately this can take quite a bit of driving and time and in a lot of cases 1 to 3 cold morning starts. Most people aren't prepared to leave their car for almost a week AFTER the original repair is finished so that in that slight off chance you have a multiple layered problem that will be discovered during this Monitor check test. We practice a process that if the system can checked , then we do it as part of the diagnostics, after the repair has been preformed, but in some cases this is just unrealistic to hold the vehicle for several days and pay them for simply driving around trying to get these Monitors to all complete. Good communication with you as a driver, your particular problem that plagued your vehicle, your driving habits, and your needs for the automobile all come to play when we are helping you through this frustrating time.