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Engine & DrivetrainDiscussions about the engine and drivetrain of your vehicle.
This is a discussion thread titled "Disconnect Battery = Fail Emissions?", within the Engine & Drivetrain forum, part of the Technical & Vehicle Assistance Forums category.
I went to a local general purpoase shop yesterday. My check engine light kept coming on, even after I reset it. Both pulling the computer fuses and disconnecting the battery cleared the codes, temporarily. I figured it was an O2 Sensor, and could replace these far cheaper myself. Just didn't know which one(s).
Interesting, the rear sensor is a quick 5 minute replacement, no lift required. The front is a bit more, but using one crescent wrench to turn another, I loosened one (and re-tightened) pretty easily. Figure 10 minutes.
The technician said it was a 155 code, Oxygen Sensor, Bank 2 Sensor 1. Difference of aggreement, but the guy who looked up the code in the computer said drivers side is bank 2. Sensor 1 is the forward sensor. So I have one on order.
But the mechanic said something interesting. After coming into the shop with his code reader, he asked if I had ever disconnected the battery. I said yes. He said that this had cleared out some codes.
Then he said that when I take my emissions test next Fall, here in Georgia, first thing they'll do is hook up to the OBD-II computer (they are doing more sophisticated emissions tests on newer vehicles). They'll see this and automatically fail me.
He said that there is a specific start up sequence that needs to be used after the battery has been disconnected. That needed to be done by the dealer. Sounds like bunk to me, but he told ME that I had disconnected the battery. . .
This is a load of hooey. If there is a particular "start sequence", you could verify that by calling the dealer and getting it from them. There are any number of reasons you would disconnect your battery, say for example anytime you do anything under the hood or do anything with an electrical component like the headlights, spark plugs, etc. etc. etc...it's not always necessary, it's more a safety thing so you don't short something (like your lifespan). There are even reasons why you would want to disconnect the battery, ie anytime you change the airflow or ignition characteristics of the engine, for example when you add an EPA-approved K&N FIPK Gen II air filter, an EPA-approved cat-back exhaust, headers, new spark plugs, etc...
Besides, what on earth could this special "start sequence" be, anyhow? "Hold your left earlobe with your right thumb and forefinger while touching your tongue to the A/C knob, use your free hand to start the engine while pumping the E-brake with your left foot..."
I wouldn't take my truck back to that mechanic if I were you ! Many people disconnect their batteries all the time. If Georgia is really doing what he says they're doing, they're looking for something other than disconnecting the battery, which means they're going about it the wrong way and you can undoubtedly challenge it if it's true--for all they know, you had to replace a faulty battery two weeks before your emissions test.
Yes there is a problem with the new emmission tests in Georgia. There was an article in the local paper that indicated these same issues and said the State was working on a solution. The procedures to go through are different on each vehicle and some are vary complicated.
That's pretty ridiculous if they're going to actually put that through. Cali has the toughest emissions standards, and the Tundra meets the reqs for a Low Emissions Vehicle when the 3rd catalytic converter is used...I would hate to think Georgia had the silliest emissions standards! Might want to contact your rep on this one, batteries and computer codes, while useful, have nothing to do with emissions--but if you install new exhaust, intake, etc. and don't disconnect your battery to reset the computer, your emissions will suffer for a while until the computer has finished learning the new fuel/air mixture. If I lived in GA, I'd be pretty steamed that my near-LEV truck (with better emissions due to airflow mods, BTW) didn't pass emissions because an uninformed suit made a silly rule regarding ECU codes. It's pretty much up to you to make sure that guy in the suit making the rules is informed, and knows that engine efficiency has nothing to do with what codes are left in the ECU--and everything to do with how the ECU and engine are *currently* operating.
This is not quite on topic, but... you were having the shop diagnose your check engine light problem right?? Just for future referrence, you can buy software from a programmer on line that will turn your Laptop or Computer into a diagnostics machine. I think that actual tool/equipment you need to diagnose engine problems is over $400. This guy charges you something like $100 for the cord to connect your laptop to the ECU and $10 for the software and that's it. Plus he offers full tech support as well.
Tundra Thunder bought this setup for his laptop when his check engine light went on. It worked great....it told him exactly which sensor was out. He said it was kind of like the setup the cop had in Fast and Furious.
He told me about it a few months ago and I totally forgot...reading your post jarred my memory. If anyone is interested, I can contact Brian to get the info for you.
Geeks unite...please tell me more about how to connect my Tundra to a laptop computer, I'd be interested in this kit. Are you sure it wasn't 100 for the software and 10 for the cable?
Originally posted by MCoupe
But the mechanic said something interesting. After coming into the shop with his code reader, he asked if I had ever disconnected the battery. I said yes. He said that this had cleared out some codes.
Then he said that when I take my emissions test next Fall, here in Georgia, first thing they'll do is hook up to the OBD-II computer (they are doing more sophisticated emissions tests on newer vehicles). They'll see this and automatically fail me.
He said that there is a specific start up sequence that needs to be used after the battery has been disconnected. That needed to be done by the dealer. Sounds like bunk to me, but he told ME that I had disconnected the battery. . .
Let me guess,when the time does come for the inspection,this mechanic can pass you for a couple of bucks,right? He's feeding you BS about the startup sequence. The inspection center is looking for trouble codes and that's it. If your vehicle is running the way it should,there won't be any codes.
As for diagnostics software,try www.obd2.com. Since I don't have a laptop,I bought an Autoxray scantool instead. It doesn't have the cool graphing capabilities PC-based scantool software has,but it does the job. When I do buy a laptop I'm definitely switching to a PC-based scantool.
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As for diagnostics software,try www.obd2.com. Since I don't have a laptop,I bought an Autoxray scantool instead. It doesn't have the cool graphing capabilities PC-based scantool software has,but it does the job. When I do buy a laptop I'm definitely switching to a PC-based scantool.
I just talked to Brian and that is the diagnostic software he got....for the laptop. Thanks for posting Ed!!
I read today in the Atlanta paper, where Clark Howard (the guy who paid $12 a night or so in NYC when he was on one of the morning shows recently <g>) talked about this.
He said that a car could fail Georgia emissions for any number of reasons. One of which is a recently disconnected battery.
He went on to say that driving the car for a few weeks afterwards "should" reset the computer. And that some shops would fail you for no codes, others wouldn't.
He failed his emissions test the first time, recently. Free re-test at same shop within 30 days. Yeah, this sucks.
the deal is that your computer must go thru 2 drive cycles so that it can determine things such as shifting points. It usualy takes about 250 miles for this to take place. Yes its a pain, i am currently dealing with it.
It's the same in Massachusetts. Now instead of actually testing the tail pipe emissions they plug into your vehicles test port and read your computer codes. If it shows the battery has been disconnected they can fail you or tell you to go away and drive for a couple of days. I think the inspection tool requires seeing a number of start sequences, if they are not there it fails the vehicle. They are assuming you are disconnecting your battery to clear codes so they don't show up on the inspection.
Disconnect Battery = Fail Emissions?
! Many people disconnect their batteries all the time. If Georgia is really doing what he says they're doing, they're looking for something other than disconnecting the battery, which means they're going about it the wrong way and you can undoubtedly challenge it if it's true--for all they know, you had to replace a faulty battery two weeks before your emissions test.
Cool!
