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Any Open Source Solutions For DIY Auto Diagnostics?
slaxx writes "As an avid tinkerer, I really want to collect as much data about my car as possible. Using On-Board Diagnostics (OBDII) sounded great to me, but the pricetags of systems like AutoTap Scanner are a bit much for my college budget to handle. Are there any free, open source solutions available? What do Slashdotters do to tinker and record the inner workings of their own vehicles?"
If $199 is to expensive for the hardware and software onyour Budget what do you expect to be able to fix on the car for cheaper?
I'm all for tinkering, and tinkering with cars used to be a great hobby. But tinkering with proprietary chip sets - with consequences not only your driving experience, but on the safety of others around you - without the proper equipment strikes me as a uniquely bad idea.
It's the underlying protocol of OBD II.
Just do a quick search on hackaday, there's been several projects in the past which may be helpful to you.
Agreed. Open Source is not a magic bullet.
When I have the time, i've been meaning to try something like this:
http://en.wikipedia.org/wiki/OBDuino
Into my Car so I can get additional performance gagues + graphs. I have the Arduino board, and can solder things here and there, I've just never gotten around to it ....
Why aren't you encrypting your e-mail?
Look at http://www.scantool.net/ . I use a Scangauge II. I went through this same thing; in the end I decided that buying a scangauge gave me 90% of what I wanted, out of the box, without having a computer clutter up the driving area, and without spending weeks hacking up something that might work but then again might not.
First, get the hardware interface: http://www.scantool.net/scan-tools/pc-based/elmscan5-compact.html with some OK software, $60 http://www.dealextreme.com/details.dx/sku.28528 $29 shipped from hong kong. Hardware isn't free unless you really do want to build your own. ELM327 is a common OBDII interface chip, and they're probably nearly identical internally Then go to scantool.net, software downloads, and find the source. Hack away. Or, go to sourceforge and look at some of the linux based obdii software.
Mixing high tech electronics with automotives has always struck me as the worst fusion of the old joke: "the difference between a computer salesman and a used car salesman is the used car salesman knows when he's lying". As an engineer it may seem like a good idea to you that the equipment is expensive, but how many mechanics are also engineers? Mechanics are often not even mechanics any more. They plug in the diagnostic and whatever it says is wrong, is what is wrong. Don't try and tell them that it doesn't make sense that a stretched timing belt is causing the shimmy coming from the front passenger wheel, darn it, that's what the computer says.
No, the reality is that the reason the equipment is expensive is so that dealerships have a corner on the market. Post-sales service is one of the largest sources of dealership income. Which, if you think about it, is a truly sad state of affairs. Besides politicians, what is the one thing people are often most cynical about? It's auto dealerships. Because no matter how educated the average person gets about the way a vehicle works, a clever desk manager can always tell you the mechanic in the back plugged in a diagnostic and it said the "[techspeak] board indicated the [techspeak] [techspeak] has failed which [techspeaks] your ignition, and this is caused by road salt erosion of your [techspeak] which is obviously not covered under the warranty".
No, making the test equipment expensive, or otherwise keeping it out of reach of the public is not the answer to either the technical issue of vehicle "safety" or the PR issue of cynical consumers. The answer is open standards, common test equipment, and education. This just doesn't do anything for dealership income, that's all.
I'm all for tinkering, and tinkering with cars used to be a great hobby. But tinkering with proprietary chip sets - with consequences not only your driving experience, but on the safety of others around you - without the proper equipment strikes me as a uniquely bad idea.
You've apparently got no understanding of what the OBD II interface lets you do.
OBD II lets you read trouble codes and operational data (sensor values, fuel integrator, ignition timing, etc.), and lets you clear trouble codes.
That's it. There's no danger at all. You can't alter anything other than clearing trouble codes.
To the original poster, google for "ELM327" to find the hardware, and "ELM327 software" to find software, including many free apps that will use the ELM interface to talk to OBD II.
I use a free app on an old Palm with an ELM327 adapter I bought off of eBay for OBD II work. Works great. I paid a little more for one that works over Bluetooth; the less expensive varieties can be plugged into an RS232 port on a laptop (old, cheap laptops are powerful enough and are more likely to have an RS232 port).
The ELM 327 is fully documented and you can write your own software to talk to it. The datasheet is here: http://www.elmelectronics.com/DSheets/ELM327DS.pdf, ELM's OBD product page is here: http://www.elmelectronics.com/obdic.html.
Putting moderation advice in your
That said, the foregoing does not mean it's a good idea for the casual mechanic to diddle with his car's computer, in part because it was probably optimized in interdependent ways that he has no chance of figuring out, because they only made sense serendipitously when being coded.
Not really. It's the cost of licences. All auto manufacturers have their proprietary commands in cars. Only most common things are specified by OBDII spec and you have to pay about $2k per year for licence of one manufacturer to get their proprietary specifications and implement them in your OBD tool.
Extreme Programming - Redundant Array of Inexpensive Developers
Mechanics are often not even mechanics any more. They plug in the diagnostic and whatever it says is wrong, is what is wrong.
Speaking as a former mechanic, fuck you very much. OBD II codes serve to provide you a place to look, nothing more.
Say for example the code is a misfire on Cylinder 3. Great. Do you have any idea how many different things can cause a misfire? It could be the ignition coil...or the spark plug...or the throttle body being clogged...or it could be a freak-one time thing that can't be replicated...or it could be something entirely different. Same thing with an O2 sensor. Just because it says "O2 Sensor Three is reading incorrectly" doesn't necessarily mean the O2 Sensor is bad. You could have bad wiring, the air/fuel mixture could be throwing off the reading, the person could have just put bad gas in it, or again many other possibilities. Have fun diagnosing that electrical problem that keeps causing the ECU to think that your Crank Positioning Sensor is bad (causing it to throw a code and making the check engine light come on), when in fact the sensor itself is perfectly fine.
It's not as simple as just "this is broken, please replace it." Many dealerships do this, but real shops do not.
Because no matter how educated the average person gets about the way a vehicle works, a clever desk manager can always tell you the mechanic in the back plugged in a diagnostic and it said the "[techspeak] board indicated the [techspeak] [techspeak] has failed which [techspeaks] your ignition, and this is caused by road salt erosion of your [techspeak] which is obviously not covered under the warranty".
If you go somewhere in which the guy up front tells you that, you demand that they put your car back together, take it off the rack, and go somewhere else. You didn't take your car to a shop, you took it to a lie.
Living With a Nerd
As an Engineer who owns and "tinkers" with many of my own cars I'd hardly consider OBDII a "safety critical system". in general it's designed to just be an output, it does accept inputs as well but unless you know what you're doing it's next to impossible to make detrimental changes to the programming.
If you're really all that concerned about making really STUPID mistakes it why not only tap into the outbound serial pin and then throw an opto-isolator on it. then you can do whatever the hell you want and not worry about damaging your engine computer.
to the OP... there are DOZENS of OBDII to Serial port adapters on eBay that sell for ~$30, I own several. You'd be hard pressed to build your own for cheaper, the hardware alone will likely cost you that much. There are dozens of free and or cheap (freediag. If you'd rather write your own SAE and ISO control the OBDII standard.
Any engineer who is too frightened to even perform some basic research on the workings of something as simple as OBDII should be ashamed of themselves.
Collector's Edition
Support your right to repair: http://www.eff.org/deeplinks/2009/05/right-repair-law-pro
Prove anything by multiplying Huge Number times Tiny Number
forgot the links:
freediag - Open Source for Linux
OBD-Diag - Not open source but free
Easy OBDII - Not open source but free (I use this most often for basic diagnostics)
You might also want to check out the MP3Car forums as they're very knowledgeable on this subject over there, and there are also several source available projects being developed there as well.
Collector's Edition
Translation of GP: You're not smart enough to bother looking at this, it's way too complicated. And besides, I make my living working on this stuff, I wouldn't want to lose any income because you learned how to fix your own stuff!
Little girls, like butterflies, need no excuse. -- L. Long
Yeah, it still is. People have been working on, and repairing, their own safety critical equipment as long as there have been cars. Brakes are definitely safety-critical. I have done mine more than once over the years as a simple example. Just because it's safety-critical doesn't mean people can't learn how to DIY repairs, as long as the information is available. All this ODBII secrecy is just for the auto industry to extort money from the auto owners.
Little girls, like butterflies, need no excuse. -- L. Long
That's all well and dandy except that the scan equipment isn't actually expensive, the OP is simply looking in the wrong places. You can order a self-contained, portable hand scanner from Jegs or Summit (without question the de-facto shade-tree-mechanic parts and tools catalogs) for about $40, you don't even need a "fancy computer" to interface with it, just the multi-meter sized device in your hand.
And the real reason the Mechanics hate doing warranty work is because the dealership screws them over too. They get paid by the job based on the complexity, and the dealership considers the same job covered under warranty to be worth about half as much. I've got several friends who make their living as auto mechanics.
It's not different to the sales department who make their money only on commission as a percentage of the profits over invoice, so to screw over the sales people the dealership sell at barely above invoice and make their money on the financing/extended warranty/accessories/etc. I've got several relatives who make their living as auto salesmen.
Dealerships will stop being scummy when they stop treating their employees like starving dogs.
Collector's Edition
If you go somewhere in which the guy up front tells you that, you demand that they put your car back together, take it off the rack, and go somewhere else. You didn't take your car to a shop, you took it to a lie.
You're right on this. However, it's near impossible to tell up front whether the place you've taken your car is a shop or a lie, since most of them look basically the same, and you only find out after your car is in pieces up on the rack which one this particular establishment is. Which is where the cynicism of the poster comes in - so many 'shops' are 'lies' that the average consumer is just assuming until proved otherwise that ALL shops are lies.
Little girls, like butterflies, need no excuse. -- L. Long
They'll read your ODB unit at no charge. Reason is, of course, they hope that you will then elect to buy the part(s) you need from them to fix it. Just go in and ask, they'll bring out a portable unit that reads the diag codes. They'll take that back to a computer, upload the results, and give you a printout.
A place to look?? Let me tell you, when I had a throttle body issue that wouldn't let the engine idle less that 1000rpm (where 800 is spec) causing the O2 sensor to go crazy and throw a code. ODBII shows O2 sensor code, mechanic replaces it and viola!! Except when I get it home and it stalls out with the same symptom. Mechanic says bring it in, ODBII says O2, mechanic replaces it, wipes his hands of it and repeat. It wasn't until the throttle linkage comes apart at highway speeds that the problem was found and fixed. No stinkin' O2 sensor, it was a throttle body issue that a old timer mechanic discovered while reattaching the linkage and didn't even bother with the diagnostics computer. So Excelcia is spot on, most mechanics aren't even mechanics anymore, they like foreign tech support that reads solutions from a symptom/code flow chart and follows it religiously.
Why don't you get rid of your current car and buy a vehicle which is old enough to be (mostly) free of microelectronics?
Easier said than done, sir. Even my '79 aircooled VW bus had a computer in it. Cars that old were much more prone to rust than current ones. The government was recently paying cash for those clunkers. They're getting rare. Not impossible, but not as easy as you make it sound to buy an old car in any kind of good shape. And not cheap if you find one in seriously good condition.
Little girls, like butterflies, need no excuse. -- L. Long
You're both wrong.
I'm a former mechanic because 5 years ago, I fractured my left and right ulna, as well as navicular fractures in both wrists. If you can tell me how to work on cars with injuries that won't fully heal for years in both wrists, I'll be glad to do it.
To the AC, I didn't want cars returned to me, which is why I always fixed what was wrong and not what I was told was wrong by a computer.
Living With a Nerd
From my original post:
Same thing with an O2 sensor. Just because it says "O2 Sensor Three is reading incorrectly" doesn't necessarily mean the O2 Sensor is bad. You could have bad wiring, the air/fuel mixture could be throwing off the reading, the person could have just put bad gas in it, or again many other possibilities.
Have a nice day!
Living With a Nerd
When will it be the Year of Linux on the blacktop?
rewriting history since 2109
That's all well and dandy except that the scan equipment isn't actually expensive, the OP is simply looking in the wrong places.
Well, I'm not a mechanic but I do like to have some idea what's going on under the hood. I have an Android phone with a bluetooth multiprotocol OBD2 interface, and I use a program (it's in the Market) called "Torque". Works very well, and does more than those handheld scanners you buy at Sears. Even allows you to log OBD info with GPS tagging, and export it. If it finds a trouble code, it will link you to a Web site that lists the possible causes for that code for many different vehicles.
It only cost two bucks.
The higher the technology, the sharper that two-edged sword.
The reason for that is not what you seem to imply. It is a question of know how. You pay for what you don't know. The security issue is something else. If you are stupid enough to change setup in the car the company is not liable for it since it can be easily proven that you are the guilty one. Most well designed cars will not allow you to do any change without proper security. You need the right codes and passwords. We have to keep coming up with cleaver ways to keep morons from screwing things up.
The reason for the high price of devices like those of Intrepid, Actia, Dearborn or Vector are that those device allow you to similate engines, ABS or transmission messages easily. If you can't do certain things common sense is that you need to pay someone who knows. Knowledge is money. If that was a larger market the prices would be much lower.
I use some of those expensive devices to test our cluster software or other devices that hooks up to the CAN (J1939, GMLAN or Ford) as well as J1850 or J1587. The price varies between $800 and $4000. When you pay $4000, about half of it is for the software.
If all you want to do is monitor things and perhaps add your own gauges or gadgets you should not attempt to go into diagnostic too often and have no need for such expensive devices. A $200 or $100 device would be sufficient, you could even create your own for cheap. Look at some STM32 with CAN or the AT32UC3C, they are quite cheap, the Atmel processor has 2 CAN.
J1850 is a pain but with most CAN protocol you can monitor faults and most information thru CAN if you know the messages. Ford, GM and Chrysler information is easily available if you know someone, it is not hidden but they don't like that data to go to Joe Blow, you have to have a legitimate reason to want the data. If you are building a device like the ones on the market you will have no problem getting them as long as you pay for them. We had to pay close to $100 for GM and it took a while while we got it free from Ford thru one of our customers. You can get the SAE specs for J1939 and J1850, it must be well over $1000 a year for a subscription.
Don't bother asking people who have those data since we are not allowed to pass those on. You want this you must pay for it.
For those who cannot afford the price of the documentation or hardware for these you have to rely on information that is published on the net and hope that it is correct or monitor the CAN for yourself and do some reverse engineering. GM, Ford and Chrysler have their own protocol in standard CAN at 500k. You must make sure that you do not create bus off conditions and that if you do, you recover quickly. Do not attempt to hook up anything on a moving vehicle unless you know for sure that the hardware is designed correctly. J1850 is still available on some vehicle but both Ford and GM have phased them out. J1850 is very tricky as it is very easy to crash the engine or transmission if you broadcast physical message when someone is broadcasting physical messages. With J1850 you must request all messages. This is not true for GMLAN or Ford which have messages that are sent on a regular basis. The GM transmission has a bug that if you try to communicate with a message that is not supported the transmission communication will crash. Do not mess with J1850 on GM engines unless you know exactly what you are doing.
For non Ford or GM trucks or RV there is J1939 (CAN 250k) and J1587 (RS485 9600 baud). J1587 is still available on all recent Allison Transmission and Wabco or Bendix ABS. It is available on most engines even though it is meant to be obsoleted. It will be around for many years because the military still use it for diagnostic. Normally when J1939 is available we use that. Allison has now J2012 for diagnostic on J1939, this is rather new, it has codes similar to OBD. Cummins and CAT are likely to follow the trend with their engine in a few years, I think that Cummins will have them in 2013 or 2014. All data is in metric on J1939 and english in J1587.
Currently you need a specially-adapted laptop, a highly proprietary cable, and some very expensive software. Garages can afford this: individuals can't.
I'm not a mechanic now, but I have worked at an auto shop. I don't think it's any different now with modern technology than how it's ever been. Good mechanics use all the tools at hand to find out what's really wrong, and then fix it. Crappy mechanics replace whatever part the flowchart, manual, or computer says is wrong and hope for the best. Computers only help both types do what they were already doing.
Of course the trouble is that most shops that I am aware of pay their mechanics based on fixing specific things - there's a specific amount they get paid for, say, replacing the O2 sensor or the throttle body or whatever, but there's no pay for figuring out what the hell is really wrong with the car. So it creates an incentive to find something to replace as quickly as possible, replace it, and get paid and move on to the next car. Even doing it wrong isn't that much of a disincentive - the car comes back and they guess something else to fix and hope that works too. Being a good guy and not getting the customer pissed is really the only incentive to do it right. I'm not saying that it's all bad or that I have a better system for how to pay mechanics in an auditable way*, but that's one of the issues.
* It's nice for the higher-up managers and accountants to do it this way because they can say "this guy replaced 20 O2 sensors this month, and each one takes X hours, so we pay him for that and everyone's happy. But this other guy says that he spent 20 hours this month diagnosing problems. How do I know he really spent 20 hours doing that and wasn't just screwing around?" You can't tell, because of the nature of troubleshooting, so it kinda slips through the cracks.
I don't reply to ACs
I just found and bought torque the other day. Great piece of software. I've had an OBDkey for a while, and had an old palm PDA mounted in the car to run the OBD reading software. Now with Torque, I was able to ditch the palm and just use my android phone. I eventually want to play with the OBD protocol and see just what I can get my car to do or not do.
It depends on what you're resetting. If it's the MIL you're wanting to reset, that may be accomplished with a simple OBDII reader that places like Wal-Mart and most reputable auto parts places will sell you for about $60-90. You're going to find that it'll cost more to read CAN or the other protocols than it's worth if all you're looking for is reset capability.
However, if you're into tinkering and are looking for understanding the OBDII or a base platform for getting it into your laptop, you'll spend $200 on the gear however you do it. If you want to DIY an autotap, you'll have fun making one as there are four differing electrical signalling protocols in play on that connector (If you're being specific, you can find out which you're using and provide the interface to that. Now having said this, you can get schematics that will work against all four protocols, firmware that will work with said hardware to drive the ISO specific one, and if you don't want to muck with fully DIY, you can buy the completed device from Stern Technologies for $149 right at the moment (Regular price is $199, but the current design's firmware only supports ISO right now so they're discounting it $50...).
You will find that you're going to have a difficult time finding cheaper or the special connector (and it's a pita- because I'd had a lark of trying to make a CarChip a' la Davis Instruments and found out just how "fun" it could be getting that connector...) that you'll need for the design. It's a pretty nifty deal at $149.
I am not merely a "consumer" or a "taxpayer". I am a Citizen of the State of Texas
I don't want to tinker, but if I fix something simple like an air filter, I want to be able to reset the console warning lights.
If you just want to be able to read diagnostic codes and reset the warning light(s), at most you need a standalone OBDII device, not a laptop, special hardware and software. Harbor Freight has them for US$50 right now, and I got one on sale there for about $30.
The only reason I know of to go the laptop route is to get detailed engine data like an emissions-testing station or performance tuning shop would want.
"...always new atoms but always doing the same dance, remembering what the dance was yesterday." -Richard Feynman
> Speaking as a former mechanic, fuck you very much.
I'm glad you were a good mechanic, but this is one of those cases where "it's just the 99% that makes the other 1% look bad." Everyone knows that finding a good mechanic is like finding a needle in a haystack--it's been a cliché for decades and it's totally true. I just spent several hundred dollars across two visits to find out why the "check engine" light was on.
Dear Slashdot: next time you want to mess with the site, add a rich-text editor for comments.
http://www.elmelectronics.com/obdic.html
Check out the ELM327 chip on that page.
$33, rs-232 control of the chip and the chip speaks to ODBII: ISO 15765-4 CAN, SAE J1850 PWM, SAE J1850 VPW, ISO 9141-2, ISO 14230-4 and SAE J1939 protocols
You set the chip up with what to monitor and/or control (Similar in style to sending AT commands to a modem) and then it does the work of giving you the data stream.
Build your own standalone test gear, with or without a PC interface.
Googling for "ODB-II Connectors" was how I found the jack ends with pins to solder to. They varied in price a bit so where I purchased from 2 years ago no doubt isn't the cheapest now.
Have fun
If that is all you want AutoZone/AdvanceAuto will usually reset the lights and read the codes for free. They'll try and sell you the part to fix it, but they don't force you to buy it.
I use VCDS on my VW because when I'm diagnosing a problem on my car, I don't want to simultaneously diagnosing my tools.
It takes time and money to reverse stuff. There have been a few open source projects, but all stalled or weren't kept up to date. I see there's a new VW project on SF.
And as far as development goes, don't ask what a CANapelicense and hard ware cost.
Reminds me of a problem my son had with his VW Jeta (turbo).
He complained that there was a noticeable miss-fire under hard acceleration.
Took it to the VW shop. They plugged in their computer analyzer and pronounced no problem.
He eventually persuaded the tech to get in the car took him out on the highway and floored it - misfire.
Back to the shop, plug in the analyzer - no reported misfire.
Basically, they told him to get lost. Especially since this was under warranty and if the VW computer showed no issue, they would not get paid.
We replaced the spark plugs.
Problem fixed.
Probably a solid state analog fuel/ignition 'controller', not really a computer in the modern sense. I guess it's a gasser thing. An '81 Jeep I used to own had one, but the '84 MB diesel I have now has no 'black boxes' at all. You can disconnect the battery after it's running if you want.
"Gold still represents the ultimate form of payment in the world." - Alan Greenspan, 1999
But can someone explain what this article is about using a car analogy?
We used to get a commission based on total parts and labor for the work ticket. One would think this would encourage us to be parts swappers and not actual mechanics, since parts make up more of the cost of a total ticket...and normally, I would agree with them. However, the culture of the shop I worked at was such that people who had a higher labor-to-parts ratio generally earned more, because they were granted higher commissions on labor, thus raising their base pay. The owners understood that not only was diagnosing and fixing the problem a better solution than just parts swapping, it was also more profitable for them because labor has no inherent upfront cost, unlike parts.
Because of this upfront cost, we were also encouraged to tell people to buy parts themselves when possible, especially on high-ticket items like BMW exhaust parts, engines, or anything else that we would charge for their first-born after markup. This made customers happy due to a reduced bill, it made the owners happy due to less money spent on their part, and it made mechanics happy because it raised their labor-to-parts ratios.
It really was a well balanced system. If you could find a way to fix a car using the same parts it came into the shop with, you were thought of very highly. If you exhausted that possibility to its fullest extent before changing parts out, but still fixed the problem, you were equally well regarded. Granted, because of this, it took us a little longer than most places to fix your car due to the extra diagnosis time...but we made damn sure it was fixed right the first time.
Living With a Nerd
As a doctor you would probably know that the scaphoid bone in the wrist is often commonly referred to as the navicular bone.
So as a doctor do you: (A) bust someone's chops when a patient mentions something like "hitting their funny bone" or some other non "technical speak" or (B) do you figure out that your dealing with a person who isn't supposed to have a technical knowledge of the human body and actually help them.
If your answer is A you shouldn't be practicing medicine with direct contact with patients and you either have Asperger's or are an asshole.
If your answer is B why are you busting the chops of a non medically trained person in a public forum (over something they shouldn't know anyway) when you knew what they meant to begin with?
Or maybe you were just being 'funny'...
A lot of people chatting on the OBDII subject today do not appear for to know what the hell they are talking about.
There is a diagnostic protocol called OBDII
OBDII Connector is the connector where you find all the communication lines used.
Not all lines are used for every vehicle.
Here are the connections for one of my tools for use with GM Engines and J1939/J1587 trucks with OBDII connector. For the bigger truck I use a connector convertor since the connector is different and round.
1 GMLAN Single Wire CAN
2 + J1850 line
3 GMLAN MS CAN H
4 Chassis Ground
5 Signal Ground
6 GMLAN HS CAN H
7 K Line
8 J1708 (J1587 software)
9 GMALDL
10 - J1850
11 GMLAN MS L
12 LSFT H
13 LSFT L
14 GMLAN HS L
15 L Line
16 un-switched VBatt
Pins 1,3,6,8,9,11,12,13 and 14 are called Discretionary, meaning that they will differ from manufacturer to manufacturer. If you look in your car you will see some pins missing, those are simply not supported.
I just maintain that the mechanics' horseshit has reached the point where I'd trust a lawyer before I trust a fucking mechanic to be honest with me. Fucking crooks the lot of them and the honest ones are usually just honest 'with people they know'. They make up their margins with customers off the street.
Sadly, I must agree with you. The shop I worked in prided itself in being honest with its customers (the first time a manager caught a mechanic trying to cheat a customer, they were fired on the spot. No second chances.) Despite our reputation and huge numbers of loyal customers, it was always very difficult to get new customers to trust us for the very reasons you outlined.
The point, as always, is that service departments in dealerships (and other shops as well) need to be hella regulated by at least 3 different agencies, with monthly audits, starting with the assumption that every single one is a den of thieves. Douchenozzles. Now, they don't even let you into the work area anymore (unless they "know" you) using some convenient OSHA rule and insurance crap and concerns for your "safety", unless you insist and threaten to take your car elsewhere.
This was something else we prided ourselves on. It's your car we were working on, and as such you had every right to see the problem yourself and, if you promised to not get in our way, even watch us do the work start to finish should you wish to. ("not get in our way" means not standing right next to us. Questions, conversations, all of that was fine...but if we had to work around you, back in the waiting room you went.)
So, tell me this. How is it suddenly ok, just for this one profession, to blame the victim for not being sufficiently observant and knowledgeable. The response always is, "well, if you don't know your car well, you can't blame them for robbing you blind." Though it's not stated that way, that's the essence of it isn't it?
We would always explain to people that when you bring your car into our shop, you aren't paying us to fix your car/replace your parts for you. You are paying for our knowledge of how to do those two things properly. Anyone can use a torch, or resurface a rotor, or make a custom exhaust out of straight pipe. Not everyone can do it properly. We always tried using simple analogies so that people had a better understanding of what was happening (my favorite being our description for drum brakes, describing the "drum" as a salad spinner and the shoes as "hands" or "the little lever you pull to stop it from spinning".), but sadly many new customers would accuse us of talking stupid to them, and acting like they were morons. It's a very fine line you walk, for sure.
I have tremendous respect for mechanics' troubleshooting skills, but zero respect for their sense of ethics.
Sadly, many people are under the impression that cars are more difficult to understand than they really are. As a result, few people take the time to famillirize themselves with even simple procedures, which in turn allows mechanics to prey on the ignorant with reckless abandon. Again, it was for this reason that we always took the time to try to explain to people how something functioned, why it went bad on their car, and what steps are required to prevent it. The way we saw it was if we could pique the interest of a consumer and make them realize that hey, these things really aren't so complicated, they might take some time to learn about them and reduce the chance they would get ripped off should they go somewhere else. Regardless, we had a zero-tolerance policy regarding ripping off customers. The owners of our shop would rather we turn away work (i.e. "Ma'am, I could fix this, but it would cost more than this car is worth. I wouldn't suggest putting any money into this thing) instead of taking money from people that we shouldn't.
And before people jump
Living With a Nerd