OBD II unit, pros, cons?

A

a.k.a. Patrick

New member
So my Expedition has sprung a "Service Engine Soon" light on the dash. I dont trust the AutoZone or tranny shops that say they will diagnose for free, so i was thinking of buying one at Harbor Freight.

Anyone have any experience with this particular model? I dont expect it to tell me exactly whats wrong vs. just shooting me a puter code which i can easily look up online. Looking for answers!



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Provides quick and easy access to Diagnostic Trouble Codes on all OBDII compliant vehicles sold since 1996

Reads and clears generic and manufacturer specific diagnostic trouble codes (DTC)

Multilingual menu and clear written definitions in English, Spanish and French

Supports multiple trouble code requests

Resets check engine light

Retrieves VIN number
 
I'm not sure if that's the exact model I bought, but I have tried a CENTECH from Harbor Freight. It wouldn't connect to my 1999 F-150 or my 2000 Audi, though the packaging said it should. It did connect to my 1998 4runner. Just try it and see...
 
advance auto and autozone are actually pretty good to work with when it comes to pulling codes. If anything, you can just write down the code it states on the meter and go home and look up what it means for yourself instead of relying on their computers. In the past though, I have never had a code read wrong on any of the cars I have brought to these two places to pull a code.
 
im sorry to say but its a total waste of money auto zone will show the screen of the code it pulled then print you out the parts you need if you don't trust them take your receipt with code on it home and do a little research....if anything don't trust the shops that charge to scan your car.... there is really no one at autozone that is smart enough to scam you..... they only know what the computer tells them (no real world ex.) and the machine is not gonna lie about the code being pulled....all that might happen is that it gives you a list of parts you dont need, what i would do is buy the cheapest part on the list and do a trial and error
 
Any OBD II reader will read codes for any car sold in the US since model year 1996. Now if you buy one from HF and it doesn't work on a car newer then 96 it may either be its a cheap product and has its glitches or that you have a grounding issue in your car.



First off to clear up confusion when you go to Autozone, Advance etc, when they read the codes on your car it does not mean they will automatically be able to tell you whats wrong. These codes will just give you clue of where to begin looking for a problem. The codes are just the car talking to you. Lets say you go to the doctor and say "Hey Doc my knees sure are killing me." He will not reply with "Sounds good to me! Let's go ahead and replace those knees for you!".



So now lets say you have 2 codes that read "System Too Lean (Bank 1)" and "System Too Lean (Bank 2)" we know that the problem is effecting both rows of cylinders. Now also it is running lean so we know either are not getting enough fuel or are getting to much air into the engine. We will now go ahead and look for a leaking intake gasket, unlocked air box, fuel pressure and fuel volume etc. This is the way to save money by finding the actual problem and not just being a parts replacer.



Now when it comes to brands and models you have to take into account your budget and your diagnostic capabilities. At the base you have one like you posted which will only show you a code. I personally own a Actron Pocket Scan Plus and I find it to be a goood budget code reader. It cost me $60 and it simply just reads the codes.



If you have a little more money ($100-150) you can pick up one that can read freeze frame data (such as a Actron CP9175). What freeze frame data is it will simply "take a picture" of the moment when the code was flagged. You will be able to see throttle position, engine load, coolant temp, mass air flow voltage, O2sensor readings etc. So lets say you get a misfire and it shows that according to the PID (parmeter ID) that the MAF is saying that its 90 degrees out when its actually 30 degrees out your MAF or the wiring to it may be bad and causing it to run rich.



So now you have a little more knowledge so next time you go to Autozone/Advance/Napa and you get a P0132 (02 sensor circuit high voltage bank 1 sensor 1) when they tell you you need a 02 sensor you can say "Hold it, let me do a little diag first"
 
Chops, thanks for the "diagnosis"....You have at least steered me towards the Actron. Looks like a nice piece of equipment for less then what I was about to spend.

Are you a garage mechanic, ASE?
 
I was a mechanic for a little while at a couple dealerships but decided I loved retail more and now work at a Advance Auto Parts. I am a ASE certified technician and am now going for my certification as a Parts Specialist. Not bad for a 19 year old I would say lol.
 
Chops said:
I was a mechanic for a little while at a couple dealerships but decided I loved retail more and now work at a Advance Auto Parts. I am a ASE certified technician and am now going for my certification as a Parts Specialist. Not bad for a 19 year old I would say lol.
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......but can ya detail? LMAO, and Im kidding. Seriously, I appreciate your help. Im ordering the scanner in short order.
 
I have the Autel MS 300 purchased from Amazon for &25.00. It has what most others do and has Can2 protocol, which can read Vin numbers, and has faster connection with newer cars. I use it to check emission status on the used cars at my dealership. Of course It will erase and read codes, except mfg's.
 
Hman127 said:
I have the Autel MS 300 purchased from Amazon for &25.00. It has what most others do and has Can2 protocol, which can read Vin numbers, and has faster connection with newer cars. I use it to check emission status on the used cars at my dealership. Of course It will erase and read codes, except mfg's.
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I have the same unit and its hard to beat for the price. Posted above was that all obdII is the same. It is not. There are three different protocols. The autel supports all three and does emissions readiness. I bought a cheapo from HF and it did not support kwp2000.
 
Hman127 said:
I have the Autel MS 300 purchased from Amazon for &25.00. It has what most others do and has Can2 protocol, which can read Vin numbers, and has faster connection with newer cars. I use it to check emission status on the used cars at my dealership. Of course It will erase and read codes, except mfg's.
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I had that one in my Amazon Wish List as well. For $28.00, seems like a deal.
 
For that price and the positive reviews I would jump on that one myself. It seems like your not yet at the point that you can decipher PIDs and whatnot and your just looking for something to give you clue at what your looking at. A code reader such as the MS300 or Atron Pocket Plus sounds perfect for you. Then if you decide you'd like to step up you can pick up a model the can show freeze frame and live stream later on.



Oh and yakky, if you want to get really technical about it there are actually 5 different protocols.
 
Chops said:
Oh and yakky, if you want to get really technical about it there are actually 5 different protocols.
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The point is they're not all the same and every code reader won't work on every car.
 
for now, I'd just take the car up to advanced or autozone and let them spit out a code for you. I've even had the guys up there on an OBDI and OBD0 look up the code in the chiltons when the computer didn't have it. you getting the car read by them doesn't require you to do any business with them, don't feel obligated. then again, you can always look for more "$.99" clearance items that ring up for $.01 :).
 
Find a good repair shop (smog) and they should give a print out. When the MIL light

is on, it means you have an emissions related problem; this could be anything from

a lose gas cap, faulty O2 sensor or a number of other things. Call a few shops.



My license has expired but i was a certified emissions specialist (aka smog tech).
 
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