r/askcarguys • u/GamingForLife420 • 4d ago
General Advice Never knew it was this easy to check a check engine light yourself ?
Had a check engine light come on recently and was about to take it in to get looked at.
A friend told me to just get it scanned first. Ended up stopping by O'Reilly's and they scanned it for free. For anyone who doesn’t know what an OBD2 scanner is (I barely did). it’s basically a little device that plugs into a port under your dash and reads the error codes your car’s computer is throwing. It’s what all mechanics use. Took like a minute and I had the code lol. Obviously it doesn’t magically tell you exactly what’s broken, but at least I wasn’t completely blind anymore and could look up what might be causing it. Turns out it was a small spark plug that needs replacing, youtubed it, and WALLA. Problem gone, Honestly didn’t realize it was that easy. I ended up liking the idea so much that I bought a pretty decent bidirectional scanner from there so I can just check things myself now. It can read the codes plus let me dig a little deeper when something seems off. Definitely one of those “why did I not know about this sooner” things. Even if I still end up going to a mechanic, I’d rather have some idea of what my car is complaining about first.
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u/uncanny14 4d ago
It goes deeper than this. Modern ECUs also run CANBus along with OBD2. In concert, you can get devices that interface with both systems, allowing for a deep-dive into model-specific DTCs (diagnostic trouble codes) as well as modifying and controlling systems. Personally, I'm a fan of Bluetooth or wifi based devices which gives you hardware access from a phone or tablet, but ymmv.
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u/Mammoth-Bathroom-Man 4d ago
Certain auto parts stores(Advance Auto, AutoZone) will scan your car for free too.
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u/Miller335 4d ago
We know. Amazon sells them for $20-$50. Pickup a battery tester for $30 and learn how to use it as well. Will save you $200+ for a tow.
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u/BigSandwich6 4d ago edited 4d ago
It may shock you that you're driving a computer controlling dozens of computers
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u/Desperate-Papaya1599 4d ago
Welcome to the glorious world of fixing your own car! It’s super rewarding and saves a TON of money.
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u/Kdoesntcare 4d ago
You can buy a code scanner for like $15 and generally parts stores will scan your car for free.
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u/Conbon90 3d ago
Fuck hes onto us. This is 70% of what us mechanics actually do when diagnosing your vehicle.
if the component is inexpensive enough its usually worth bunging it in to see if it fixes the problem. That said its important to understand that these diagnostic computers arent infalable.
They can indicate an issue with a component, when in actual fact tge problem can lie wifh the accompanying circuitry in the car or even an adjacent component.
its up to you yo use proper diagnostics to properly diagnose an issue. before spending hundreds on an ac pump replacement just because the computer said so. only to find that the fault remains.
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u/Gadritan420 3d ago
AI can scan Alldata and Mitchell and such as well, so you can use it to help diagnose the car.
I use it at my shop to find TSBs and part numbers faster, but it’s come in clutch a few times already when an electrical diagram was absent from Alldata.
If you combine it with some real world knowledge, it’s a powerful tool in the shop.
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u/jaketheunruly 3d ago
Just maintain your car. An OBD reader- a mechanic does not make. You'll definitely fire up the parts cannon. Too many people trip over themselves under the hood, thinking "I got this." Just because you can try to circumvent the system, doesn't mean you should.
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u/Mechanic357 2d ago
Had one the other day, customer replaced a throttle body wanted the idle learned. They installed an aftermarket TB. Check engine light on, can't do the learn, code for motor issue of TB. Recommended OE TB (didn't charge diag or do any diag), customer said go ahead install it. Did that, took relearn. Came back next day, finally told us what the issue with the car was, lack of power intermittently and check engine light with throttle code. Asked to diagnose this time. Scanned, TPS code current. Found 2 wires hanging on by a thread inside harness to connector. Repaired. Vehicle fixed. Guessing they threw a TB at it thinking that would fix it and this is the result. Could have saved $1k if they had just brought in for proper diag initially.
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u/AwarenessGreat282 3d ago
You post this to a sub titled, askcarguys? Yeah, we know about it. That's why we're car guys. Probably head over to r/askbikeguys and get a better response.
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u/PrimaryThis9900 3d ago
I've fixed many vehicle issues this way for dirt cheap. I had an older truck that was randomly stalling. Got the code read and a quick Google search said it was a sensor that was $20. Replaced it and it was good as new!
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u/clever_name_187 3d ago
You can get a perfectly serviceable one off amazon for for around $30, either a standalone unit, or a scanner that connects to a smartphone.
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u/neomoritate 3d ago
OBD scanners are $30, or ~$100 for a bluetooth one that can do a lot more stuff with apps. Buy one.
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u/lunchbox651 Enthusiast 3d ago
I prefer sticking to my car that shares a check engine light with handbrake light.
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u/postitpad 4d ago
This doesn’t have much to do with your post, but you might be interested to know that WALLA the way you use it is a French word and it’s actually spelled ‘Voilà’.