The AM Forum

Hey Crew, I was over at the auto parts store getting some erl and filters to stock the shelves and I came across one of these beauts.

(http://users.wpi.edu/~smithw/Odd_Photos/OBD-II_Computer.jpg)

Should be a nice addition to the apparatus here at 'GF labs.  ;D

What is it? Some kinda new marital aid?

Yeah, you just have to add batteries... Teehee, nah keith it's an OBD-II "On Board Diagnostics" code scanning computer. You plug it into your car and you can read the data stream comming out of the ECU computer to see if all the sensors and controls are operating optimally on your engine.

If your "check engine light" comes on it cost about $100 bucks to have them read the codes at a garage or at the dealership to diagnose the engine, a pop.

It's a nice thing to have because you can plug it into your car and check the tolerances of the controls. Nice to know before hand of impending doom.

Yep, they're the cat's BAs, alright.

I forget when OBD-II became the mandate (96? 97?), but those units work on all cars sold in the US after (insert correct year here), regardless of manufacturer. If you've got an older car, you still need to jump through whatever proprietary hoops were built in (jumper the plug and count the engine light flashes, and so on).

They could have standardized these interfaces long before they did, but at least they finally did. Great companion when you blow an O₂ sensor. You can even use them to make the engine deliberately misfire!

Outta curious-ousity, what was the approx. price tag?

--Thom
Kilimunjaro Africa One Zulu Goat Cheese

Very Good Bill,
The guy sitting behind me has one. Heck most people would pay $20 to get to use it one time. I was told you need to purchase more software for some car models

oooo! What part store carries it? I think I want one. I had a light come on in my XYLs Jetta and the garage charged me 50 bux to hook it up.

Some auto parts stores will connect one to your car for no charge to find diagnostic codes which cause the check engine light to illuminate. The check engine light on my 98 Blazer came on once, a mis-fire on #5 cylinder or so the diagnostic code said. Decided to buy the gaget to clear any further glitches which caused the check engine light to come on. In the republic of Mexifornia, during a smog test on your vehicle if the check engine light is ON the car, truck, etc., fails the smog test and you can't get plates for the next year until repairs are complete and of course the vehicle passes the smog test. Good gaget to clear false alarms or help make the decision to take the beast to a dealer with proper tools and techs.

Hoopie,

Lots fun of stuff here to talk about, I knew this would make a good thread in QSO. Good technical disucssion but not really radio related.


Yes my 93 tercel was as you described, I had to jumper two pins on a jack and read the flashes, not too bad.

My 86 maxima was similar, the ECU was located under the front passenger's seat. You had to pull it out and switch it into diagnostic mode so that it would flash the codes, pain in the rear. Most of the work that I did on that car was using a multi-meter, vacuume pumps, vacuume gauges and a timing light. That car had California emissions so it was a nightmare under the hood, but I kept her running in tip top shape anyway. When I left Hawaii the nice lady that bought that car got a really good set of wheels, I spent a lot of hours under that thing.


Very reasonable, Tom, they had a very simple model that was $100, it reads the codes and you have to look them up manually with you PC. This one has a few more bells and whisles for $250, you can watch the sensors in real-time, etc... It came with software (on CD) and PC interface cable, the OBD-II (1996 standard) cable, carrying case, manuals, etc... It will work with OBD-I with an additional cable, also it will work with the big 3's individual proprietary pre '95 interfaces with special adapters.

Dealerships have computers that will give you a technical diagram of the automobile and show you exactly where the problem is and probably print out the replacement part # for you etc... So the sky is the limit for the star-trek models, cost wise. That why it cost a fortune to have it done at a high-end garage, it requires a degree in automotive technology to do the work, which is a prerequisite for certification.

The ultimate is using a laptop hooked to the ECU, have somebody drive and you tweak her up. As seen on tv and in movies


Ed, I got mine at the CAP warehouse/outlet in Milford.


Yes, here in Massachusetts if your check engine light is on or if theres a belch and it comes on momentarlly while on the dyno, you fail inspection automatically.

My 93 tercel failed emissions on all gasses, there wasn't anything wrong with any of the sensors or controls and the thing ran good, no hesitating, plenty of power and good gas mileage; a real head scracher. There was no tell tale smell of rotten eggs but it did burn a little oil being 11 years old and having 200kMI on it.

So when it failed I got handed a stack of papers an inch thick that I had to fill out when I performed the repair work, which was the real pain in the butt.

To pass I basically gave it a super tune-up. I chaged the fuel filter, air filter, oil/filter, rotator, cap, wires, plugs, catalytic converter (under $100 bucks and after 130kMI they're on borrowed time anyway), PCV, tweaked the timing, injector cleaner, etc... I took the thing rip-roaring down the highway to get it piping hot, pulled into the inspection station (2nd inspection is free if you fail and take it back) and it passed with flying colors.

When I got my Tacoma I really didn't get much money on the trade-in of that car, which was a good set of wheels. I should of gave the thing to somebody that needed some basic transporation.

Anyway, the check engine light came on in my sister's car for a few days and it went away. Could of been that the engine was miss-firing or knocking because of crappy gas, who knows.

It's a must have for the home mechanic, like myself.  :)

As Keith said, starting around $99 and up. Several different models are available. Here's their URL if you want a lot more info:

http://www.actron.com/

My "Check Engine" or "Engine Mtce" or "Danger Danger" (I forget what it really said" light came on my Toyota Sienna dash when I driving down the Turnpike last year. Turns out it is Toyota's way of telling the driver it's time to change the engine oil. There would have been one less Oh s**t! if the light indicator just said, "time to change oil" rather than engine mtce or check engine, etc.

Pete, my name is Bill.

Same here in NJ - if the light is on, don't even bother going to the inspection station. 

Another thing that can trigger the "check engine" light is if the gas cap is loose or has a leaky seal.  That happened to my father's car and he drove it for years.  Only when NJ came up with this new light law did he pursue it. A new gas cap fixed the light.

Yep, that check engine light could mean anything. After reading some of the book you can even diagnose the airconditioner. My truck is very simple under the hood, but the ECU is used to cycle the AC compressor so there's probably some sort of sensor that I can read... Nifty toy!

Duh! Having too many windows open on the screen at the same time caused my brain to skew.
Sorry Will.

On another note, the really bad thing is, once you take it to be inspected even if you've got four weeks to get it done; if it fails they instantly take your good sticker off and replace it with a failed emissions one... It makes you feel really warm and fuzzy when they bend you over like that, and of course the garage that fails you instantly tries to sucker you into letting them repair the car.

Looked up the website and it looks like the big part stores carry it. I think it would pay for itself someday. Wonder how many cars are driving around with tape over the check engine idiot light? TNX Bill :)

 Thats right! On my wifes Jetta,the  MAP sensor was on the blink and the mechanic wanted $285 to repair it.

I have a Snap On Scanner in the shop.  In addition to checking all engine emission controls , sensors, switches, etc. It also reads body and transmission codes.  In some vehicles ,  it will even tell me if the vehicle has a bad power door lock, or a problem in the windshield wiper/washer circuits.

The scan tool is a nice little tool to have.  I have OBDII software that I load into the laptop and connect the laptop to the car.  Gives out performance curves when driving around too.

Gandy gadget to have!  But be careful.... read on.

Here in NY all the garages that do inspections were required to purchase DMV supplied PCs which includes the diagnostic link to the vehicle. Cars older than ?? (something, I don't recall), but not newer than 1 year must get connected during inspection.  They figure new cars (< 1 year) are OK & covered by manufacturer.

The linkup passes the VIN to the big computer in the sky, passes along the mileage, and the diag codes if any.

The guy at the garage told me it can tell how long the on-board computer has been collecting codes.... if the on-board computer has been reset recently the car will not pass inspection!  'Recently' is either time or number of engine starts, I don't recall.

So if you have the tool, be careful about resetting that pesky "Check Wallet" light on the day of your inspection!

Big Brother is watching.

73, Bill   N2BC

The first step toward recovery is admisson that a problem exists. ;D

#1 problem with electronic engine controls is when people start fooling with them instead of looking at normal routine maintenance issues first.
The OBDII standard is a nice thing for us geeks to use as an information source however. Bill, you are smart to look at the numbers BEFORE anything goes wrong. We need a few more like yourself around here.

What will they think of next.

If your Check Engine light comes on, push the blue OnStar button and an OnStar Advisor can:
Run a remote diagnostic check of your engine.
Tell you whether to continue driving or find a safe place to stop and wait for Roadside Assistance.
Contact a Roadside Assistance provider with your exact location.
Assist you in scheduling a service appointment for you if necessary.

Hehe, if you think that's bad, you should of seen how much it cost for a new crank angle sensor on my 86 maxima just because the idle was a little rough... and I changed it myself  :o

Yes any emissions repair at a shop is big $$, not really because the parts are expensive in all cases, it's the 3-5? year warranty on the parts and labor. Some level of it is federally mandated, some is state mandated (California, etc). Yes when I had my first inspection of my Tacoma they did hook the emissions computer up to the OBD-II ECU connection and they uploaded the information to big brother.

It's actually a good thing in a sense because I've known of a few people that have hooked devices up to the pulse train comming from the transmission sensor for the odometer, so they can put 175kMi on a car and have the odometer read 35k, to absolutely rip off the person buying their used car.

Yep I've known a few mechanics that change a few parts, charge $X, reset the codes and say it's all fixed, then a month or so down the road the light comes on again and it's back to the shop for the same treatment.

My Brothers wife's car was knocking on acceleration and the CEL came on. We went down to the auto hobby shop on perl harbor and had one of the technicians read the codes. The computer came up with bad EGR. Turns out the EGR was bad, it wasn't the valve though it was the vaccume modulator diaphram control, so I changed that and the engine still knocked and the CEL light came on again because of the knock sensor in the block.

It was funny cause the technician told me to just resistor the sensor(s) like there was nothing wrong...

So being myself I pulled out my vaccume pumps/gauges and started poking around and couldn't find a damn thing wrong So, I pulled out the compression gauge and found that the engine had a blown head gasget around one of the cylinders, real fun 15 hour repair... After I got done fixing it, we put the car in the want classifieds... Like my uncle would say "a true mechanics dream"

You are 100% correct Bill.
If the Check Engine Light, known in the profession as a MIL (Malfunction Indication Light) is on, and then reset right before a vehicle inspection, the car will most likely fail.

The reason is simple, what you are alluding to is "monitors". A Monitor is an acknowledgement that the system it watches has run through all procedures.
Some of these systems take extended driving to set. See http://www.fordscorpio.co.uk/obdindetail.htm for details on monitors.

For example, let’s say that you have an OBD code for an “Evaporative System Leak”, a common code to set, can be set with a loose or defective fuel tank cap. If you erase that code, and drive into an Inspection Station, the monitor will most likely not be set, and the car will fail inspection.

States have wised up to the resetting the MIL and it has become more and more common to require that the vehicle has run all monitors before passing for inspection.

The other thing to keep in mind that there are TWO sets of codes. One set is the “generic” OBD codes which are the same on a Porsche and Chevy. But most manufactures also incorporate a second set of “manufacturer specific codes” which offer greater detail and insight into the problem, I find that all too often the generic codes are just very basic indication of the fault, and all too often lead the tech on a wild goose chase.

Having the factory diagnostic tool is the key for the more sophisticated faults and systems.
For example, we had a Saab convertible come in with the MIL. My tech scanned the system with the Saab computer and could not only tell exactly what that fault code was, but he could tell the date, time and the speed of the vehicle when the fault occurred. Our client go quite a kick out of knowing the problem occurring on such and such a day at 7:35PM when the vehicle was traveling at 85mph, seems she had lent the vehicle to her son during that time!

Some of the late model European imports, Volvo is an example, almost require the factory tool for diagnosis and service. I realize that this defeats the intent of generic OBD. For example, let's say we have a 2003 Volvo V70 XC in the workshop. We plug the car’s diagnostic connector into our workshop computer using a software and hardware system called VADIS (Volvo Aftersales Diagnostic and Information System). VADIS tells me the VIN of the car, exact model and features –sunroof, trans type, mileage, options, etc. VADIS is our service information system as well, displaying service procedures, specs, even a parts catalog. Once VADIS is running, it then scans the car for faults, and connects with the Volvo computers in Sweden to download any software updates or patches – not kidding! When a fault is discovered we have to record online what was fixed, the action and part number, before we can reset the code. Volvo uses this data to correct faults and track service issues.

Care to guess the cost of VADIS? About $10K per year to our workshop, hence the $75 diagnostic fee, software dowload/updates are additiona expense to the customerl. A good idea, yes, cheap no, but then again the “by guess and by golly” approach is the most expensive around. We routinely see vehicles which have had several hundred, in some casses, several thousand dollars of "repairs" by other facilities, only to find the simple fix. The downside of this system, only 5 in the state of Maine, my business, one other independent and three new car dealers. Afraid to say that this is the trend, and it really locks out the small and general repair shops from any degree of complex diagnostic work.

Now here is the best angle. Right now we have to have the car present in the workshop for diagnosis and updates. I was recently speaking with my Bosch rep and was informed that Bosch and others are working on a system where the car will be diagnosised and then updated via wireless connection. This is what GM can do with On-Star, but takes it a step beyond. So may go out to start your Volvo, BMW or X car some morning and find that pesky Check Engine light is off, or that transmission shifiting glitch is corrected. As cars become more and more software driven, we'll soon see the day when you visit the service facility perhaps once a year.

Interesting world we live in...thank you Mr. Hertz, Marconi, Tesla and Armstrong.

Very cool indeed Bruce, I hate to think of the day when they won't even have to clock you with a radar gun or a laser rifle. Big brother will have his fingers into everything and you'll just get a ticket whenever your spedometer crosses over the speed limit. I've heard (I don't factually know) that the police are now hooking up some cars to their computer systems and using it as evidence to people that dispute speeding tickets.

Yeah, good info Bruce.    But, tomorrow is now.   

 I saw a show on Discovery a while back, the focus was on GPS technology.  They did a piece on vehicle tracking.  One trucking company dynamically downloads engine computer settings based on where the truck is located and where it's headed.  They dynamically set performance parameters to achieve maximum efficiency and fuel savings. When the truck is headed into the Rockies they enable more horsepower, take it away when it gets back to the flatlands.

Well I had some fun with the new gismo today. I hooked it up to the car and took her for a spin down the highway, it was neat cause I was watching the state of the fuel injection system in real time. This will come in real handy for tracking down that last few ignition noise problems that I have. I've already gotten the level down to about S5, but there's always room for improvement. It's kind of a futile task because as soon as I drive down a road with powerlines or I'm in heavy traffic I still pick up all the radiated garbage from the other trash generators. I'll have to load up the software that came with the computer and do more reading. When my sister comes over tomorrow to get her oil changed, I'll be doing some investigation into why her MIL came on a few weeks ago.  :)