Every Car Should Allow You To Decode A Check Engine Light As Easily As This Motorcycle Does

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For decades, car and motorcycle manufacturers alike have been feeding vehicle owners bad information. I’m not talking shifty marketing speak, but the idiot light. Modern vehicles have a fairly decent grasp of what’s happening under the hood, and when something happens they want to tell you what’s going on. However, the vast majority of vehicles out there just use a combination of ominous lights to signal problems. If a check engine light comes on, you have to plug in a scanner to even get an idea of what’s going on. In this world where everything has a screen, that’s absurd. And that’s why Zero Motorcycles does something awesome that, so far as we can tell, is still extremely rare today.

It won’t come as a surprise to many of our readers that I’m a moderator and an administrator at multiple Smart Fortwo groups and forums. I’ve known the ins and outs of these cars for over 16 years, so I try to use my knowledge to help others out. Otherwise, the complete and total history of the Smart Fortwo will just live rent-free in my head.

One of the most common posts I see is when someone’s Smart encounters a problem of some kind, causing the check engine light to illuminate. The person then takes a picture of the check engine light, uploads it, and asks the group what the problem is. Check this out below:

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We as car enthusiasts already see the immediate problem. What’s the code? You can’t diagnose a car’s issue from a vague picture of a check engine light on Facebook. The person on the other end of that post often isn’t a car enthusiast. They have no idea what the check engine light means.

In my experience, now you’re instructing this person to drive to an auto parts store to get a code scan. If you’re lucky, they return with whatever codes were pulled. A lot of times they don’t because that’s stressful and they have no idea what they’re doing. I can’t blame them. I may love cars, but for many, it’s just an appliance.

In the end, I’m left frustrated, wondering what’s the point of the check engine light if the car’s not allowed to tell you what the code is. Every car sold today has some sort of display, be it for infotainment, a backup camera, or gauges. Even your old Chevy Trailblazer has a screen technically capable of telling you something, anything more than that pointless check engine light.

David Tracy

I understand that this isn’t a huge issue in the grand scheme of things. Basic code scanners can be bought from a million different places for less than the price of a decent meal at a restaurant. But the everyday person, like my parents, don’t know that. They’ll just roll around with the light on wondering what it is or take it to the dealer. It took years to teach my mom how to use a computer.

Introducing her to a diagnostic scanner would be another learning curve that’s way longer than it needs to be.

It shouldn’t be this way. Your car knows something is wrong with it, so it should be able to broadcast that to you, no tools needed. This is a take Jason Torchinsky wrote back in 2012, and honestly, the argument against the check engine light is even stronger today now that everything comes with a screen of some kind.

Before we continue with the wonderful solution I’ve found, here’s Jason’s short explanation for why cars warn you with a worthless amber outline of an engine, anyway:

This has its roots, of all places, in the 1969 Volkswagen Type III, one of the first cars with electronic fuel injection. The “electronic” part of that meant that there was a crude computer brain that managed the system, and could scan for error conditions. Other manufacturers soon had their own systems, and by 1996 an actual, standardized system, called OBD-II, was developed and mandated by law for inclusion in all cars sold in the USA.

OBD-II is actually a terrific system. A global standard for helping to diagnose car issues, with standard connectors and error codes? What’s not to like?

What’s not to like is that when something goes wrong, all the average motorist sees is that little drawing of an engine bisected by a lightning bolt. And all that tells them is basically nothing. The “check engine” light is the MIL (Malfunction Indicator Light) of the OBD-II system, and illuminates whenever a fault is detected. To see exactly what sort of fault takes a “special scanner” that plugs into the OBD-II connector.

With that out of the way, Jason and I have found two wonderful exceptions to the rule. An engineer over at SRT made sure the Viper actually read out trouble codes to you. Now I’ve found one more.

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For the past 10 months, I’ve been testing a 2023 Zero DSR/X. It was smooth sailing until winter, when the bike was totally taken out by the week of subzero temperatures the Chicago area experienced in January. I don’t want to think about ice much longer so let’s keep talking.

The freeze absolutely murdered the motorcycle’s high-voltage battery and 12-volt battery. I first had to charge the 12-volt battery just to get the computers to wake up. Then I had to heat up my rented garage to at least 32 degrees before the high-voltage battery bothered to join the chat. Overall, the motorcycle was outrageously unhappy. The first boot after the subzero freeze presented me with a check engine light. But there was a twist.

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When the bike booted up, a bunch of errors popped up on the screen with simple explanations. The screen warned of a throttle fault, and a dying 12-volt battery, among other things. Frankly, this was amazing. It could have just given me the check engine light and left me to figure out what’s going on.

Back in the day, some cars with early diagnostic systems like OBD1 used a sort of Konami Code with your key to get into the correct mode. Then the check engine light flashed a sort of Morse code. Some cars used a little light to do the same, or in the case of my bus, a freaking beeper. Sometimes it’s really hard to tell the difference between the beep for error code 44 and error code 77, I tell you what. This is so much better!

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Even better was the fact that I had even more options to view the errors. The left side of the handlebar has a selector switch to bring up the bike’s menu. While you’re in there you could tell the bike to charge longer, swap around your gauges, look at performance data, and more.

But the coolest part for me is the fact that you can look at stored error codes. The screen should give you a code and a short description of the error. If you want to know more, pop open your copy of the owner’s manual and it’ll give you a longer explanation of what each code means. While it’s not a full diagnostic tool, it points you in the correct direction without any special tools or anything other than your fingers and 30 seconds of time.

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If you think the bike is wrong, and sometimes it is, you can open a menu and clear the codes from the bike itself and go on your merry way. Sometimes, if you crank the throttle before the green ready light comes on, you’ll get the throttle fault. It’s super easy, barely an inconvenience to clear that.

This is the kind of system Jason has been advocating for. Zero Motorcycles, unlike the vast majority of the world’s automakers and motorcycle makers, trusts you with knowing what your motorcycle thinks is wrong. It’s incredible because if you’ve been riding for long enough, you know that pulling codes from a motorcycle can be hard, sometimes involving jumper pins or other tricks. None of that is happening here. You just flip through a menu and look at the code for the answer. Your owner’s manual can then tell you more. Knowledge is really power here.

Zerodocumentation

So, I’m left coming to the same conclusion as Jason. The check engine light as it exists today is garbage and should be changed. In its place should be a system that easily tells you “hey, buddy, I’m feeling a bit broken today, care to check out my throttle?” The systems are already there, the manufacturers just have to do it.

But don’t do it just for us car enthusiasts. Do it for the person who doesn’t care about cars. It breaks my heart to read when a car or motorcycle owner has no idea what to do with a check engine light.

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Or worse, I sometimes read stories of when a vehicle owner takes their car to a shop and ends up thousands of dollars poorer, just to find out that they paid for work that was totally unnecessary. They had no idea their cars didn’t need all of that work, but they went into it blind. If their car told them what was wrong, they could at least level the playing field against a potentially bad actor of a mechanic.

There have been times I drove to a Smart owner’s house to help them diagnose a problem before they took it to a shop. It shouldn’t have to be that way.

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So, I land on Jason’s side of pleading for any lawmakers that will listen to push for a mandated system that allows a car or a motorcycle to give them more than those so-called idiot lights. Come on, automakers and motorcycle manufacturers, your vehicles already know something’s wrong. Just allow them to tell us.

Until then, this is another thing I applaud Zero for doing. Zero Motorcycles doesn’t have to let you know what’s wrong, but it does, and that’s cool. Every vehicle should be like this.

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52 thoughts on “Every Car Should Allow You To Decode A Check Engine Light As Easily As This Motorcycle Does

  1. Mercedes you and Jason are both correct. Infact my Isuzu Vehicross had an O2 Sensor that couldn’t last the 100,000 miles required so government regulations required a check engine light come on automatically at 90,000 miles even if the O2 Sensor was operating correctly.
    On another note car salesmen are some of the most misinformed car people. I now drive to a car part store on any test drive drive for an OMBDII read with a print out. It isn’t 100% but it will show all cases scenario and give you a whole lot of bargaining power on a used car. Put the used car reptiles on their ass. Argue worse case scenario. And if no warnings enjoy piece of mind.

  2. Yeah, it would help on newer cars
    On the classics and older vehicles it was just literally: going to check the engine, look at it and actually use your brain to look for basic stuff
    Hood open:
    -Look for smoke (if none, add Lucas smoke! Ha ha) Check oil, battery connection, air filter, belts, anything out of the ordinary, etc then antifreeze/water last so it has time to cool- once there’s no pressure, check and add if needed
    We already know all this stuff, I’m just pointing out that it was literally check engine with the implication that you already know how to do all the basic stuff and had that stuff in your car already back in the day. People were self sufficient and knew how to do it in the 1st place. Obviously, cars needed more maintenance…it is great that newer cars require a lot less along w/ being able to look at all these codes can help tremendously. It still just blows my mind when people just don’t have a damn clue on even the basic stuff- that’s a general statement so a good example is that I’ve heard people say the ol’ line: “I don’t care/know what it does or brand it is…as long as it runs/drives and gets me to where I need to go, that’s all that matters” and I can’t help but cringe. I do partly understand that w/ daily driver cars/non-car people, etc but what gets me is the ignorance/naivety…to the point where they don’t even know how to check fluids, battery, air filter, washer fluid/wipers,etc…even do a jump start or change a tire. Yes, newer cars you can mess stuff up w/ a jump but that’s ridiculous when it can help you when stranded…also, yeah now it’s more dangerous to change a tire on the side of the road (because of fools that have ruined it for everyone) but they should still know how for if they’re in the middle of nowhere. Yeah, I get the convenience of roadside service if needed and for people w/ health problems who can’t chang a tire, etc but I just can’t fathom someone who just acts dumb and says “I don’t know, it’s broke, I don’t know what’s going on w/ it, I’m a dummy, come save me so I can just act like a robot and drive, not pay attention to anything, talk/play on my phone/screens being a distracted driver while severely risking everyone’s lives around me because I’m in a bubble and don’t give a shit about anybody but myself”
    Eventually it will catch up to these people and they will be surprised when they hurt a bunch of people and or themselves and wonder why they are in prison- hopefully for a long time!
    Ok, rant over, just had to vent

  3. Let’s see, modern cars have a tablet on the dash, not to hard to interface this into the on board diagnostics, gin up some menus linking codes to info pages. Link in some suggested solutions. Add a digital version of the owners manual. Done ezpeezy. They could probabky charge a couple of hundred for it.

  4. While this is an awesome idea, it will never happen. Car dealers depend on their ability to rip off consumers. People bringing in their car because the check engine light is on is like a blank check. The dealer’s service department can make up anything they like and charge a huge amount for it. If anyone proposed a law that cars need to give you the error code, the dealer association would lobby intensely to make sure it never passed.

    1. That light on the dash? Oh, no! That means your blinker fluid reservoir is completely dry, and uh, your muffler bearings are shot. That will be $2,000, please. (Tightens loose gas cap) Yup, you’re all set!

      1. Ha ha yeah also horn fluid
        Yup, I will never, ever understand how someone who takes advantage of so many people who are obviously oblivious about their car can look themselves in the damn mirror and live w/ themselves

    2. Yeah, would be an excellent feature, but sadly it’s basically locked behind a pay wall. I can imagine the sheer excitement of whoever came up with that idea on the management meeting.

    3. I don’t know why anyone would take their car to a dealership for repairs if it wasn’t covered by warranty. If the warranty is up you should give the dealership a third finger up and never see them again.

    4. Another aspect is how freaked out the average owner if they were to get some of the terrible sounding but fairly innocuous codes. “It says there’s a lean error on 4 cylinders, I want a new engine under warranty, you only changed a sensor and didn’t even check the rest of the car”

  5. an old android phone with a $15 amazon obdii sensor can really help…That being said diagnostics on cars should not be that hard, just tell us the code so we can google it

  6. Freaking Infintis from mid 2000’s will tell you the vague location of the code like “emission systems error detected”. Then you can press the I believe labeled see more. It then provides you a thousand word document on your tiny screen about all the things that could possibly cause the error and recommends you bring it to the dealership. Like, you sure you couldn’t just tell me outright? I had an 04 Volvo S60R would display the code and let you clear them from dash, it was slick.

  7. Well, some cars do give you some indication. My Mercedes (a ’23 and a ’24) give out messages like “Steering Assist inactive.” My ’06 Ferrari gives messages on the screen like “TPMS System Failure” (whenever it’s cold). Even my ’87 928 has a bunch of lights with messages (all over the dash – they are just specific trouble lights) in addition to the “!” trouble light. And if you aren’t sure how series a “!” fault is, you can press the “!” button, and if the lamp goes out, it’s not serious. If it stays lit, it is.

  8. My Kona N will tell you the actual OBD-2 code on both the infotainment screen and the Blue Link app. It doesn’t tell you what the code means, but it at least gives you the alphanumeric code so you can look it up.

    I think they don’t give you a description of the problem because, for instance, an O2 sensor fault could be the sensor itself or fueling or spark issues. So they don’t tell you the code because even simple codes might require an actual diagnosis.

  9. Even stranger, there are cars that have this feature. Most Stellantis SRT products (Trackhawk, TRX, hellcats) and even the Scat Pak cars have a menu that allows you to read Diagnostic codes.

    Odd that they went to all the trouble to make that a menu option when its the same basic menu setup in all thier vehicles, but only enable it on the higher end stuff.

  10. My 2014 Yamaha Fz09 will show diagnostic codes on the display. You will still need a manual to find out what the codes mean.
    The newer models now need an OBII reader to diagnose. I’m sure it is to force the average rider to take the bike to the dealer.
    I hear complaints that Triumph check codes can only be cleared by a dealer.
    Welcome to the future.

  11. Car Wizard brought up the glaring issue with the OBI diagnostic tools. Some manufacturers require you to buy the module that would work with specific model, specific year, and/or specific whatever.

    He had to decide whether to invest hundreds or thousands of dollars for the module that is probably used only once.

    1. VW do this. My Polo started to flash up an error light (not the general ‘check engine’ light, a different one), which two different generic OBD2 scanners that I tried, couldn’t detect. I ended up getting charged £40 to get it read at a specialist shop*.
      There is a fantastic bit of software for working on VWs called VCDS, but it’s >£200, and that’s the ‘home’ version that only allows you up to three VINs. Buy a 4th car and you’ll need to shell out for the pro version.

      (Fortunately it turned out to be just a faulty brake light switch, which was about £6 and two minutes to swap)

      1. My mum has 2009 Polo (9N3) kitted to the hilt with creature comfort, DSG, and Climatronic. Thankfully, I found the procedure for displaying the error codes by pressing two buttons simultaneously when starting the engine. It doesn’t always show everything wrong with the car, only with Climatronic system.

        I am still figuring out why the power lock on the rear passenger door work intermittently. The door can still be opened from inside if the power lock doesn’t work. VW does make the access to the power lock mechanism tough…

  12. Is engine failure imminent or can it wait for my next day off to figure out why the check engine light is on? It would be nice if the car could give at least some idea of the severity of the problem.

      1. After years of owning some beaters with acceptable full time engine lights, I can attest a blinking engine light (in my case paired with the chime dinging) really alerts you that something has gone wrong.

        It was a bad coil pack so I was still able to drive a little while with 1 less cylinder.

  13. The Cadillac “Digital Fuel Injection” systems from the 80’s would tell you the codes, allow you to read PIDs and clear codes for both the Powertrain and Body control modules by pressing the correct buttons on the HVAC panel. Of course due to the era it was just a handful of codes and PIDs but that was par for the era.

  14. I don’t have to use it much, but I like having an OBD-II scanner. It’s annoying that I can’t find one that works with CarPlay though. They provide a lot more info than simple diagnostics for troubleshooting.

    1. Apple is really picky what gets onto CarPlay. I expect the profit margin is just not there for small developers / hardware makers to invest in the time and money.

  15. motorcycle enthusiasts are different, and they don’t ride because they need to, but because they want to. if we add this for cars and they get the P0420, “Cat below efficiency threshold’ most of them will get a dog. And for this code, it’s almost never the cat, just the secondary O2 sensor

    That’s why we are enthusiasts, we like to figure our own stuff. We will always have a more advanced OBD reader, or diagnostic tool

  16. The thing about DTCs is that they do not tell you what actually needs to be fixed on the car. The DTC indicates a problem with a component or system, and then YOU need to determine what needs to be examined, tested, and/or replaced to correct the issue. If critters have chewed your wiring harness (a common problem), and the car then sets a DTC indicating TPS Volts High, replacing the TPS absolutely will not fix the car. Auto parts store folks love to look at it as “read code, replace part” but there’s often more to it than that.
    Funtime with diagnostics: 80’s-90’s Chrysler products will give you “blinky codes” for the fuel injection system if you cycle the ignition key ON-OFF-ON-OFF-ON. It’s a proprietary system of 2-digit codes. Late 90’s and 2000’s Chrysler products will show OBDII-standard P-codes in the odometer if you do the same ON-OFF-ON-OFF-ON key cycle. I think that the first Chrysler products that displayed the P-codes were the 1998 Dodge Intrepid & Chrysler Concorde. My old 2002 neon and 2005 SRT-4 did it, too. I think that my 2008 Grand Caravan also can display P-codes.

    1. There’s a good reason for this. It might not be the sensor in question, as you point out yourself. Too much information can be a dangerous thing, like the temperature gauge story from a couple months back.

      People are already challenging enough; the last thing anyone needs are people that don’t understand codes going apeshit on mechanics because “the car said replace this, you lied to me.” Etc and so on. Hell, even I’d follow along at first without really questioning “is it *really* the fuel pump? Or is it a gauge, or sensor, or wiring harness, or or or…”

  17. I need to take the opposing opinion here. If someone is technically un-inclined enough to not be able to work a scanner and pull codes, they’re even less likely to do the proper troubleshooting and root-causing that happens after they pull the codes. They’ll continue to throw new oxygen sensors at the car without investigating the connectors, cabling, and other failure points that could contribute to an oxygen sensor fault.

    That would definitely sour the DIY spirit for a lot of people. Idiot lights are just fine the way they are. For us enthusiasts, we can use the proper tools to fix the issue and get our cars working again. For the general public, they just need to know if they should take the car into the shop. Giving any more information than that is bringing them up to the level where they know enough to really make a bad mess of things.

  18. The best OBD1-era system I encountered was the Lucas GEMS 14CUX system used on the Land Rover Discovery 1 and contemporary Range Rovers. There was a little LED numeric code display tucked under the passenger seat that you could pull out on a wire tether. Then you straightened a paper clip and pushed it through a hole in a plastic housing that was next to the tethered LED display to jump some contacts together. The LED display would then show codes which you could look up in the service documents. It was brilliant.

    There was more information you could get with a laptop and special (read: expensive and unobtanium) Land Rover interface, and later somewhat more affordable aftermarket readers. But the onboard display was generally good enough for repair diagnostics and incredibly simple to use. Once you knew it existed, of course. Many owners didn’t even know about the secret little diagnostic tool hidden under the seat until it got publicized in Internet forums in the early 2000s.

    Every British car enthusiast loves to joke about Lucas / the Prince of Darkness / Inventor of the Short Circuit and all that. But their electronic engine controls were actually very well-thought-out and reliable. The 14CUX added much improved diagnostic capability, including the hidden onboard display. It was all very clever and well-engineered in the tradition of the earlier British computing innovations of the 1980s. (I owned a Sinclair computer back in the day; they had their faults, but they were remarkable tech in terms of miniaturization and economy. An entire generation in schools grew up learning on the BBC Micro, another landmark early microcomputer. And the ARM processor family that keeps making waves in tech news today is a British computing invention.)

    1. “The best… system I encountered was the Lucas… system”. Look! I took your statement out of context to make you look bad! Seriously though, it’s nice to hear someone point out that Lucas wasn’t all bad. Also, your other examples of British computer innovation were apt. Of course, classic British sports car enthusiasts are entitled to criticize the Prince of Darkeness sometimes. 😉

      1. Lucas is the reason I gutted the low-voltage electrical system in my Triumph GT6 EV conversion and replaced it with a craptacular low-end GM wiring harness. Which is a massive upgrade.

      2. The old 6V and early 12V systems were where Lucas’ electrical systems got their reputation for headaches.

        Although given the large number of problems resulting from bad grounds (And consequently electricity’s tendency to find an alternate ground, often through a connection that’s not suitable for the current) I tend to lay the blame on the particular metals used in a lot of British cars. They often have a propensity for corrosion around connections — especially grounds, which may just come down to metallurgy rather than bad electrical design. And the old 6V positive-ground systems also encourage galvanic corrosion even more, adding to the problem.

  19. I mentioned this earlier today, but my 03 CTS would give you codes on the nav screen. No explanation, but you could take your P0703 code to Google and get a good idea of what was going on. And it would let you interrogate all 14 or so computers on board.

  20. My Bluetooth OBD2 reader helped me run the Dr. Prius app to better evaluate the state of my hybrid battery a few years ago.

    The reader has mostly been unused since then. I bet it would be more helpful if I actually had errors to diagnose in this thing since it’s trouble-free to begin with.

  21. The first-gen Holden VL Commodore (which I have written about here: https://www.theautopian.com/how-australias-holden-brand-narrowly-survived-the-80s-and-ended-up-with-nissans-most-legendary-engine/ ) required you to remove the
    passenger side kick panel and check out two flashing LEDs for 11 possible fault codes:

    https://www.boostcruising.com/advice/35161-Self-Diagnostic-Test-FOR-THE-VL-Computers.html

    While the second-generation Commodores had you bridging out a connector:
    https://forums.justcommodores.com.au/threads/checking-your-computer-for-faults-vn-vp.3937/

    A little Bluetooth OBDII dongle lives in each of our Subarus, everything else is carburetted so the Mk1 Mod 0 Eyeball and Ear setup still rules the day for diagnosis.

    1. The VL Commodore setup would have originally been a Nissan thing, due to the Nissan-derived RB30 engine. In the 90s I played with a lot of JDM Nissan engine transplants in my cars and friends’ cars, and all Nissan EFI computers of the time worked the same, viewing LEDs through a hole in the side of the computer module and deciphering the flash pattern. The FJ20ET I had in a Datsun 180B SSS even used the identical optoelectronic ignition sensor in the distributor that the RB engines used, so I was able to test the ignition system using a home-made test module based on a design someone came up with for working on VL Commodores.

  22. For what it’s worth, a lot of OBDI-era BMW’s from the 80’s and 90’s have what is called a “stomp test,” where you put the key into the run position and press the throttle pedal all the way down 5 times. Then the CEL will blink in a pattern, and you get your fault code from that, so like 1221, then you Google it and find that it’s Oxygen Sensor 1. Easy.

  23. I’ve always assumed they kept the engine codes obscured to drive visits to their service dept because like you said, most people won’t spend $40 on a scan tool or know to stop by O’Reilly’s for a free scan.

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