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Am I being taken by my mechanic?

Recently I brought my car (1996 Toyota Corolla, manual transmission) in for it’s annual inspection. The mechanic pointed out that the struts needed to be replaced, and there was a problem with the battery terminal, so he replaced that. When I returned after the car was repaired, he told me the car had failed the emissions test, but that this was because he replaced the battery terminal. He said to drive the car for 100 miles and then bring it back to his shop and it would pass the emissions test. My question is - does it make sense that replacing the battery terminal would cause a problem with the emissions test? And secondly, should he have done a $500 strut replacement on a car that was failing the emissions test? I am concerned that when I bring the car back, it will still fail emissions and I will have sunk $500 into a car that I don’t want to put alot of money in to. Thanks in advance for any help you can offer.

you can’t change a “battery terminal”. The battery has 2 terminals, and they are part of the battery! Did you misunderstand the mechanic? Even if he replaced the battery, that has nothing to do with the emissions test. Ask him for the emissions report.

He shouldn’t do any repairs without your permission.

Well, I just looked at my bill, and there is a charge for 15.95 for a battery terminal in the parts section. I had approved the replacement of the battery terminal, or whatever he did to it, so that is not an issue.

I have a copy of the Vehicle Inspection report and it just says that it failed the emissions test. Should he have checked the emissions first before doing the struts repair so that I would know the full scope of the work that needed to be done on the car?

I have an addendum - I cans see that it is the Oxygen Sensors, Catalytic Converters, and the EGR System that are “Not Ready” according to the report.

maybe this is some strange battery I’m not familiar with. Unless this is the clamp on the end of the wire that connects to the battery.

I assume you ok’d the strut replacement?

I think trying to define the correct order in which repairs are performed is drawing a very thin line. Just my opinion.

now you are getting into the big $$. However, what he may be saying is that the computer (EGR) is reporting an error that could be the Oxygen Sensors or the Catalytic Converters, not that all of them are broken. Sounds like, if you want to keep this car running, you have to take it away from the inspection station and get it to someone who works on toyotas.

Thanks for your help. I appreciate your judgment call on the “thin line” because I don’t want to be unreasonable, but it’s hard to know whether one is being treated fairly when you know nothing much about cars! Have a good one!

My guess is that they replaced either the positive or negative cable that attaches to the battery. When the battery is disconnected, the ECM resets. A certain number of car starts are needed for the sensor register in the ECM to fill up and provide a valid reading. That is why the mechanic suggested driving 100 miles - to get the restarts and drive time need to set a valid OBD-II code.

Searching on the internet: (apparently terminal can mean either the post or the connector that attaches to the post)

Battery post: part of the battery, where you connect the wires
Battery terminal: 1. same as battery post
2. same as battery terminator
Battery terminator: Connector on the end of a wire that clamps to the battery post.

jtsanders has the best answer. The terminology as to the “terminal” has different meaning to different folks. I agree that replacing the “terminal” requires disconnecting that “terminal” lead. When doing so it takes the vehicle computer to learn its functions all over for some period of time. Relax

I don't know about your car but some cars will give a fault if the battery has been disconnected.  It then takes a few start drive cycles for the sensors to have a base line and to turn off the light. 

As for the emission issue, you likely don't have one, you have a CEL issue and it will likely go away following his advice.

The computer must have a certain amount of history stored in order for it to pass emissions inspections. When the mechanic disconnected the battery the computer lost all its history, and that is why it failed. When driving to restore the memory of the computer make sure some miles are at highway (60-70mph) or you will likely fail again. If your check engine light doesn’t come on you will probably have no problem with passing the test. This has nothing to do with the strut replacement.

And that is exactly what you’d expect to see if the battery is disconnected. Those are called monitors and their status is reset each time power is removed and restored. The intent is to thwart scofflaws that would simply cycle battery power right before an emissions test and pass because the history was erased. The monitors require varied driving conditions and a preset number of drive cycles in order to become ready again. The emissions test cannot pass until all of these monitors show ready.

In states with emissions testing, there has to be a minimum number of drive cycles in order to pass the test. This is because some people disconnect the battery just before a test to reset the computer and erase old codes. Getting the number drive cycles has to do with starting the car and warming it up to normal temperature more than just driving 100 miles. I cleared a code and just drove normally for two days and passed. I drove in for an emissions test and forgot I had worked on the vehicle. The engine does need to learn the vehicle sensors for lowest emissions. If your engine is on the edge, it can take 100-200 miles of varied driving to produce the lowest emissions. Your mechanic should have done the test before the repairs and just didn’t explain this very well.