# Idiot lights and the idiots that look at them. **URL:** \ **Category:** The BBQ Pit\ **Created:** [January 3, 2009, 6:52pm UTC](https://boards.straightdope.com/t/idiot-lights-and-the-idiots-that-look-at-them/479722 "2009-01-03T18:52:51Z")\ **Posts on this page:** 20\ **Page:** 3
**Author:** ![bucketybuck](https://avatars.discourse-cdn.com/v4/letter/b/898d66/32.png) [@bucketybuck](https://boards.straightdope.com/u/bucketybuck)\ **Post date:** [January 4, 2009, 6:01pm UTC](https://boards.straightdope.com/t/idiot-lights-and-the-idiots-that-look-at-them/479722/41 "2009-01-04T18:01:03Z")
> [@Justin\_Bailey](#): > > Because getting it checked out will set you back $100, even if nothing is wrong. But it could cost you an extra $2000 if there was something wrong and you ignored it? ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [January 4, 2009, 6:17pm UTC](https://boards.straightdope.com/t/idiot-lights-and-the-idiots-that-look-at-them/479722/42 "2009-01-04T18:17:23Z")
At our auto shop a typical “check engine light” incident often (not always, but often) follows this sequence. 1. Owner sees light on, takes car to parts store and gets it diagnosed. 2. Parts store sells owner some repair parts based on the diagnosis. 3. Owner takes parts home, installs same on car. 4. “Check engine light” still comes on. 5. Repeat steps 1 thru 4 several more times. 6. Owner finally brings car to us. Is put on hugely expensive analyzer loaded with hugely expensive software. 7. Very experienced technician interprets code, and repairs problem. **7A. Technician finds $20 part that is bad, and give an estimate for same plus labor 7B. Customer whines that he spent over $1000 trying to fix check engine light. 7C Technician thinks, it wouldn’t have if you brought the car here first.** 8. Owner drives car away with unlit “check engine light”. Owner usually becomes a regular customer. **OR 8A. Customer whines about high cost of repair on his vehicle.** Added a few sub steps for you. ---
**Author:** ![GusNSpot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gusnspot/32/436_2.png) [@GusNSpot](https://boards.straightdope.com/u/GusNSpot)\ **Post date:** [January 4, 2009, 6:38pm UTC](https://boards.straightdope.com/t/idiot-lights-and-the-idiots-that-look-at-them/479722/43 "2009-01-04T18:38:41Z")
A 1952 Chevy works just fine. For me. I can fix it. I will wait for it to warm up. I will check the oil and radiator fluid each time. I know how to use a choke cable. I am OK with the MPG it gives. I am OK with the power limitations. I am OK with the short service life of the engine and parts. Most people are not OK with all this. They want good MPG. Instant drive ability. Not to need to warm up. No to need to check under the hood. Lots of horse power that runs cheap and at all altitudes with no fiddling. Modern materials and a running life of 300K miles and 10 year warranties. They, as a society, want cleaner air and all that stuff. “They want electrical and electronic comforts.” All this requires the kind of control that only computers can give and machines that are so delicate and complicated that they can not be fixed under a shade tree. As a society we are in that transition area where the old farts want some control and the cost is still to high a percentage of our available money. When cars cost as little as cell phones and are as easy to replace, then the need to care for them will have caught up to our expectations. We are not there yet but many people are lulled into thinking that we are because of the great dependability that they have achieved. And having someone else who will foot the bill… No matter the place or the times, I feel that the need to know how to build shelter, find food, provide transportation on land & water and be able to be self sufficient to at the minimum, be able to survive, is a basic skill we are wrong to let young people grow up without knowing. As important as transportation is to the individual and the personal style of transport we demand, it requires me to be able do the utmost to keeping it working. Apparently for many, that is not as important. YMMV ---
**Author:** ![Tuckerfan](https://avatars.discourse-cdn.com/v4/letter/t/eada6e/32.png) [@Tuckerfan](https://boards.straightdope.com/u/Tuckerfan)\ **Post date:** [January 4, 2009, 8:31pm UTC](https://boards.straightdope.com/t/idiot-lights-and-the-idiots-that-look-at-them/479722/44 "2009-01-04T20:31:10Z")
> [@bucketybuck](#): > > But it could cost you an extra $2000 if there was something wrong and you ignored it? Yeah, and if you _don’t_ have the $100 to have it checked out, the $2K that it _might_ be (and Murphy’s Law dictates that if you have to scrape up the $100 to have it checked out, it’ll be a wasted $100 because it’ll turn out to be a false alarm) is so far beyond your means that its not even worth thinking about. The simple fact is that car makers **don’t** want people poking under the hood of their vehicle, because they think their customers are idiots (this last part might describe why they’re in so much trouble). Now, to be fair, there _is_ a bit of truth to this, cars these days are incredibly complex, and have a _lot_ of computing power under the hood. Still, it seems to me that there _is_ a way for car makers to keep idiots from fumbling around in places where they shouldn’t, and not have customers feel lost when some stupid light, with a bizarre symbol and/or acronym, begins flashing on the dash. (And telling customers to “read the manual” is **not** going to work. Few people do, and to describe the writing in them as “dry” is like saying Death Valley can be a “bit warm” in the summer.) All your “big box” home improvement stores offer free (or low cost) training sessions on how to tackle a job, why not car dealerships? (Saturn did at one time, but I don’t know if they still do or not.) The car makers could even work out a deal with the insurance companies to get the insurance companies to pay for it, or to reduce customer rates if they take the courses. (It should, in theory, reduce the risk of accidents on the road, as people who’ve been through the course will realize that having the brake light on is _really_ fucking serious.) Also, ditching the need for a damn code reader would be a big help. Put a bluetooth, wifi, USB, or Cat 5 connector on the car, and let people at least be able to get the information via a web page, if not a program installed on their PC. ---
**Author:** ![bacon](https://avatars.discourse-cdn.com/v4/letter/b/b782af/32.png) [@bacon](https://boards.straightdope.com/u/bacon)\ **Post date:** [January 4, 2009, 11:00pm UTC](https://boards.straightdope.com/t/idiot-lights-and-the-idiots-that-look-at-them/479722/45 "2009-01-04T23:00:19Z")
> [@Mach Tuck](#): > > Another poster said some parts stores will hook up your car to a computer for free to get the diagnostic codes. Which ones? I’ve always been annoyed that my dealer wants $35 just to get the codes, and not actually do anything about them. Advance Auto Parts will also do this. I use them quite frequently, and they are always very accomodating. The dealerships, on the other hand, will sell you a franistan for your ruptured blarwort if you let them, even if your blarwort is totally cromulent. JMHO ---
**Author:** ![Hanna](https://avatars.discourse-cdn.com/v4/letter/h/b3f665/32.png) [@Hanna](https://boards.straightdope.com/u/Hanna)\ **Post date:** [January 4, 2009, 11:25pm UTC](https://boards.straightdope.com/t/idiot-lights-and-the-idiots-that-look-at-them/479722/46 "2009-01-04T23:25:14Z")
I remember on one of my old vehicles (Geo Tracker) I was watching the odometer closely, because i wanted to see it roll over to 50,000 miles. The very second it rolled over, the check engine light came on. I was a block from my home, so I drove it home (rather than leaving it on a very busy street). Coincidence? We also have a van (used) that the check engine light has been on almost since the day we bought it 9 years ago…dealer said gas cap problem, but many trips to the dealer and independent mechanics and we still cannot find a problem with it. So from my experiences, lights don’t always mean abandon your car immediately, wherever it may be. ---
**Author:** ![Daylate](https://avatars.discourse-cdn.com/v4/letter/d/9dc877/32.png) [@Daylate](https://boards.straightdope.com/u/Daylate)\ **Post date:** [January 5, 2009, 2:03am UTC](https://boards.straightdope.com/t/idiot-lights-and-the-idiots-that-look-at-them/479722/47 "2009-01-05T02:03:07Z")
RICK, splendid additions. Every one of them is dead accurate! \*\*\*7A. Technician finds $20 part that is bad, and give an estimate for same plus labor 7B. Customer whines that he spent over $1000 trying to fix check engine light. 7C Technician thinks, it wouldn’t have if you brought the car here first. 1. Owner drives car away with unlit “check engine light”. Owner usually becomes a regular customer. OR 8A. Customer whines about high cost of repair on his vehicle.\*\*\* Looks remarkably like a “been there, done that” situation. BTW, I’m waiting for someone to start a thread about fixing vehicles that have failed their emisions tests. That often generates some hilarious over-the counter discussions. ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [January 5, 2009, 2:28am UTC](https://boards.straightdope.com/t/idiot-lights-and-the-idiots-that-look-at-them/479722/48 "2009-01-05T02:28:29Z")
> [@Daylate](#): > > RICK, splendid additions. Every one of them is dead accurate! > > Looks remarkably like a “been there, done that” situation. > > BTW, I’m waiting for someone to start a thread about fixing vehicles that have failed their emisions tests. That often generates some hilarious over-the counter discussions. Got several of the T-shirts to prove it also. 😃 ---
**Author:** ![The\_Surb](https://avatars.discourse-cdn.com/v4/letter/t/ce73a5/32.png) [@The\_Surb](https://boards.straightdope.com/u/The_Surb)\ **Post date:** [January 5, 2009, 3:19am UTC](https://boards.straightdope.com/t/idiot-lights-and-the-idiots-that-look-at-them/479722/49 "2009-01-05T03:19:52Z")
Or 1. 2002 Accord misses a shift point 2. CEL comes on to acknowledge a transmission error 3. Owner’s wife takes car to dealer 4. Dealer wants $80 just to **check** CEL and tells wife no way a transmission fault can set the CEL. 5. Wife calls owner who tells her the dealer mechanic is full of shit and asks her to check his eye color. 6. Wife says “yep, they’re brown”. 7. Wife takes car to AutoZone and the dude at AZ says transmission error set a CEL, see this h’yer manual even shows the code. AutoZone resets the CEL free of charge. Full of shit mechanic can pound sand. ---
**Author:** ![spinky](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@spinky](https://boards.straightdope.com/u/spinky)\ **Post date:** [January 5, 2009, 3:36am UTC](https://boards.straightdope.com/t/idiot-lights-and-the-idiots-that-look-at-them/479722/50 "2009-01-05T03:36:24Z")
Anyone griping about having to pay the mechanic $100 to read their trouble codes should go buy one of [these](http://www.thinkgeek.com/gadgets/car/8426/) (or a similar device; I got a [BMW-specific one](http://www.peakeresearch.com/) before these generic OBD ones got so inexpensive). I keep mine in my trunk and it’s saved me many a trip to the mechanic. At the very least, you can call up your mechanic and say “it says there was a misfire in cylinders 1-3” and they can advise you whether you should just reset the code and see if it happens again, drive the car in for a look-see, or turn it off immediately and have it towed in. Well worth the money. ---
**Author:** ![Algher](https://avatars.discourse-cdn.com/v4/letter/a/3d9bf3/32.png) [@Algher](https://boards.straightdope.com/u/Algher)\ **Post date:** [January 5, 2009, 3:36am UTC](https://boards.straightdope.com/t/idiot-lights-and-the-idiots-that-look-at-them/479722/51 "2009-01-05T03:36:51Z")
> [@bacon](#): > > A lot of the chain parts stores have the code scanners, and will plug up for free, to tell you which codes have been thrown. ('96 and up, I think) > > I love my ‘70 F100. Gas mileage sucks, but if it breaks, I can fix it without Bill Gates’ help. '67 Mustang for a daily driver. My commute is short enough that I don’t worry about the cost of 91 octane she drinks. No lights - just good old gauges. Parts are cheap as hell, and don’t require a supercomputer to install. Adjusting your fuel / air? You need a flat head screwdriver, not a usb cable. ---
**Author:** ![Ruken](https://avatars.discourse-cdn.com/v4/letter/r/f475e1/32.png) [@Ruken](https://boards.straightdope.com/u/Ruken)\ **Post date:** [January 5, 2009, 1:43pm UTC](https://boards.straightdope.com/t/idiot-lights-and-the-idiots-that-look-at-them/479722/52 "2009-01-05T13:43:20Z")
> [@LSLGuy](#): > > Which is why the US loses billions of dollars of productivity annually because most users of Office can barely operate 2% of the features, but would gain by being able to use 10%. This probably isn’t the best thread for it, but I’d be interested in learning about those 8% (I don’t know what I might be missing out on.) **ntucker** , that’s a nifty gadget. I might get myself one. ---
**Author:** ![control-z](https://avatars.discourse-cdn.com/v4/letter/c/eada6e/32.png) [@control-z](https://boards.straightdope.com/u/control-z)\ **Post date:** [January 6, 2009, 7:56pm UTC](https://boards.straightdope.com/t/idiot-lights-and-the-idiots-that-look-at-them/479722/53 "2009-01-06T19:56:02Z")
My “Check Engine” light was on in my 98 Contour for years. There was nothing wrong with it, it got regular oil changes, 25MPG, good power, ran smooth. I wasn’t about to run to the dealer every time that damn light came on. ---
**Author:** ![wonky](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wonky/32/393_2.png) [@wonky](https://boards.straightdope.com/u/wonky)\ **Post date:** [January 6, 2009, 8:52pm UTC](https://boards.straightdope.com/t/idiot-lights-and-the-idiots-that-look-at-them/479722/54 "2009-01-06T20:52:51Z")
> [@control-z](#): > > My “Check Engine” light was on in my 98 Contour for years. There was nothing wrong with it, it got regular oil changes, 25MPG, good power, ran smooth. I wasn’t about to run to the dealer every time that damn light came on. Hey, mine was a Contour, too. That’s the one where I could get it to go out by racing the engine. ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [January 6, 2009, 9:16pm UTC](https://boards.straightdope.com/t/idiot-lights-and-the-idiots-that-look-at-them/479722/55 "2009-01-06T21:16:57Z")
A serious question for \*\*Rick \*\*and **Gary T** - Most cars these days have multiple internal data buses and networks. More and more cars also have large LCD displays for the radio and navigation. On my truck, the radio/nav unit is on at least two buses - one for “entertainment” data and one for vehicle status - it has a fairly rudimentary sub-menu that’s connected to the odometer to show when the next oil change is due. The basic elements are all there… Why can’t we see a nice clear depiction of the car’s OBD status and faults on that big built-in LCD rather than having to plug in a code scanner? As professionals, would you hate this for “stealing” what you’d otherwise charge a customer to tell that a sensor’s gone bad, or would you like it for letting customers come in saying “The car says the MAF sensor’s bad” or “It says cylinder 3 is misfiring” and saving you some time and futzing around with trying to extract what the customer means when they say the car’s not acting right? ---
**Author:** ![Skywatcher](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/skywatcher/32/254_2.png) [@Skywatcher](https://boards.straightdope.com/u/Skywatcher)\ **Post date:** [January 6, 2009, 9:19pm UTC](https://boards.straightdope.com/t/idiot-lights-and-the-idiots-that-look-at-them/479722/56 "2009-01-06T21:19:11Z")
> [@Zany\_Zeolite\_Zipper](#): > > You know, it is the Y2K9, why can’t I get a car with a little German woman in the dash? You want Dr. Ruth in your dash? ---
**Author:** ![Santo\_Rugger](https://avatars.discourse-cdn.com/v4/letter/s/e95f7d/32.png) [@Santo\_Rugger](https://boards.straightdope.com/u/Santo_Rugger)\ **Post date:** [January 6, 2009, 10:02pm UTC](https://boards.straightdope.com/t/idiot-lights-and-the-idiots-that-look-at-them/479722/57 "2009-01-06T22:02:31Z")
> [@gotpasswords](#): > > Why can’t we see a nice clear depiction of the car’s OBD status and faults on that big built-in LCD rather than having to plug in a code scanner? Because you haven’t looked hard enough for it? On my Charger, you have to hold the compass and music buttons on the steering wheel for about 3.5 seconds. It has a lot of cool stuff in that menu, including a digital speedometer, digital engine temperature, and perhaps the coolest, a digital gas gauge. I believe it works by measuring the capacitance of the fuel tank; at any rate, it givs a readout with precision to the nearest pint. ---
**Author:** ![control-z](https://avatars.discourse-cdn.com/v4/letter/c/eada6e/32.png) [@control-z](https://boards.straightdope.com/u/control-z)\ **Post date:** [January 6, 2009, 10:36pm UTC](https://boards.straightdope.com/t/idiot-lights-and-the-idiots-that-look-at-them/479722/58 "2009-01-06T22:36:13Z")
Especially on a car with a LCD screen, there’s no technical reason why it couldn’t display the full set of OBD-II variables on the screen, under an Advanced menu or whatnot. ---
**Author:** ![bucketybuck](https://avatars.discourse-cdn.com/v4/letter/b/898d66/32.png) [@bucketybuck](https://boards.straightdope.com/u/bucketybuck)\ **Post date:** [January 7, 2009, 12:25am UTC](https://boards.straightdope.com/t/idiot-lights-and-the-idiots-that-look-at-them/479722/59 "2009-01-07T00:25:35Z")
I wont speak for any fully qualified technicians, but I dont actually see the value in every driver having access to the full list of current fault codes in any vehicle. Two things to consider, first, it is rare that the listed codes will tell you what the problem is, they are a signpost, thats all. They can tell you what area is having trouble, but not what is causing it. An experienced technician can look at the codes and from experience have ideas as to where to check next. There are hundreds of possible fault codes, and I myself have looked at printout after printout from vehicle after vehicle and yet I still can do very little from the codes themselves. You also need the training and the experience, which very few people have. So my point is that say if the vehicle could easily list all current fault codes on the dash itself, what use is that really? It would be data that is useless to the majority of users, many of whom wouldnt give a rats ass if the codes where available or not. For the others, those that are interested enough to find out what the codes actually mean, well what next? Perhaps you will be able to clear the fault yourself, or at least find out that its a minor fault that you can safely ignore for a while? Thats the ideal situation, but is it worth it for the manufacturers to add in a personal code reader for the few cases where it is only a minor fault in a vehicle driven by somebody with the gumption to actually KNOW what that fault means? I am not sure it is. This leads to point two… which is that it wont matter to the technician if a customer comes in and says that the problem is with the MAF sensor, or the ABS sensor, or the main ECU, or anything. It wont matter because it CANT matter, the technician has to follow his own diagnostic path. Sad experience has shown me the trouble involved in assuming any repair or taking other diagnosis at face value. I once had a technician waste twenty hours trying to diagnose a fault with the braking system on a Mercedes sprinter van. The van was ‘just’ failing the brake tests regardless of what parts where changed. What was the problem? A faulty wheel speed sensor, which would have been replaced a lot earlier if the customer hadnt told us that another Mercedes garage had already replaced ALL of the wheel speed sensors with new parts. They hadnt. Moral of the story? A good service advisor wants as much information as possible about how the vehicle has been acting, what its history is, what conditions the problem occurs in, etc etc. What he doesnt want to know, is what the customer thinks the problem is. Its useless information, because a good technician still needs to follow the proper diagnostic tree. Good information will help to rule out different branches very quickly, but the rule holds true in my experience. So where does that leave us? We have information that most people wont care to know, that others wont know how to process, and for those who will know the codes it wont affect repair bills in the garage anyway. Should we really put this information as standard on all car diplays? ---
**Author:** ![control-z](https://avatars.discourse-cdn.com/v4/letter/c/eada6e/32.png) [@control-z](https://boards.straightdope.com/u/control-z)\ **Post date:** [January 7, 2009, 12:29am UTC](https://boards.straightdope.com/t/idiot-lights-and-the-idiots-that-look-at-them/479722/60 "2009-01-07T00:29:30Z")
Can’t hurt, might help. The cynical side of me says it won’t happen so that dealers can continue to charge people $80 just to hook their car up to the computer. [Previous page](https://boards.straightdope.com/t/idiot-lights-and-the-idiots-that-look-at-them/479722.md?page=2) [Next page](https://boards.straightdope.com/t/idiot-lights-and-the-idiots-that-look-at-them/479722.md?page=4)