OBD II scan tool advice needed - PeachParts Mercedes-Benz Forum

MS Fowler · #1 08-04-2013, 03:56 AM

I want to buy a scan tool. I have had my codes read at the local parts store, but recently had a catastrophic failure that required the car to be towed to a shop. They charged me $89.95 to read the codes. Not to mention $140 labor, and $125 parts cost. All for a Crankshaft Position Sensor. Part cost should have been under $75--that is the manufacturer's list price, and about .5 hours labor.
I know, I "should" have investigated. But sometimes you can't. The car just died. Had been running fine, then, like someone turned a switch, it died...on the crest of a stretch of road called "Dead Man's Curve" no less. When the shop called with the estimate, I agreed, so I can't complain too much. But once burned, I become twice as careful.
So I want an OBD II scanner to keep in the car in case I ever have it totally die again. I see some very inexpensive ones on Amazon and the like--under $40! I also see some over hundreds of $$. So what is the difference?

If all I want is to be able to read codes, won't the least expensive do the job?

Any personal experience with various makes and models of readers?

Air&Road · #2 08-04-2013, 06:14 AM

Do you just want a code reader, or do you want a scanner? I have a scanner, which also of course reads codes. Other than scanning and watching out of curiosity, I've never really used the scanner. A code reader would have served me the same.

A generic code reader will read basic engine codes and could have read your crank position code. For any codes beyond that, you would need the brand specific equipment. Many brands, especially MB's have other controllers for everything from airbags to convertible tops. Equipment for reading such codes is not really practical for the DIYer.

Hope this helps.

BTW, I have an autotronics scanner. They are quite common, seemingly rugged and reasonably priced and readily available.

daw_two · #3 08-04-2013, 07:44 AM

I've used this one for about 5 years and had it permanently mounted on my dash in my Dodge Truck. I enjoyed setting the display to monitor volts, speed, AVE mpg, instant mpg, etc.. When I bought mine, the price was about $40-$50 cheaper. YIKES !!!

ScanGaugeII : Linear Logic - Home of the ScanGauge

Good Luck in your search.

Medmech · #4 08-04-2013, 09:05 AM

I bought the 13.95 Bluetooth cheapie on amazon that works with my android tablet and smartphone it does the regular code scanner but also does real time diagnostics. I think everyone should have one.

aklim · #5 08-04-2013, 09:12 AM

For my F-body and Y-body, I could simply use a paperclip and get the codes. Short out 2 female terminals on the ALDL and it would flash the code. The code might be meaningless in and of itself. I had a W202 with a code. Left and right O2 sensor, sometimes one or the other. MAF was fine or so the code reader said but if you look at the readouts, it wasn't as good as it looked. Replaced the MAF and life is good.

I'd spend the money and get a good scanner instead of a code reader since the codes don't always tell you exactly what is wrong.

Hatterasguy · #6 08-04-2013, 09:31 AM

My Chevy forced me to buy a cheap one from AZ last year because it pops a CE light every few months.

TwitchKitty · #7 08-04-2013, 10:55 AM

A code reader that will reset the codes will probably do 90%+ of what you want it to do. Go cheap and get a vacuum pump/tester and a good multimeter too. Multimeter with temp probes is great.

Curiosity, did you look up the codes to see if your car sets a code for the crank sensor?

MS Fowler · #8 08-04-2013, 04:34 PM

Quote:

Originally Posted by TwitchKitty

A code reader that will reset the codes will probably do 90%+ of what you want it to do. Go cheap and get a vacuum pump/tester and a good multimeter too. Multimeter with temp probes is great.

Curiosity, did you look up the codes to see if your car sets a code for the crank sensor?

Yes, its a pretty common failure--2003 Hyundai Elantra. ( wife's car originally; now my work vehicle). Also a code for 2nd O2 sensor, slow to warm up. That one sets the CEL every 2 months, or so for 100 miles and then the CEL goes out. Its not catastrophic as the engine still runs fine with that semi-failure. I will replace it at some future date, but there is no hurry.
For any CEL that allows the engine to run, the parts stores reader service is fine, but when its such that the car can't be driven, then you need a reader or you get towed.
What is the difference between a code reader and a scanner? I think the terms are often used interchangeably.
Alkim--on pre-96 cars there was a way to read the codes. Ford used an analog multimeter and you counted the "sweeps" of the needle. But in 1996, with the advent of OBDII, they all use a common architecture, and codes. I suppose that is an improvement.

kmaysob · #9 08-04-2013, 05:18 PM

Code reader-pulls generic codes. You then open a code book and see what that code means for your vehicle. A scanner pulls vehicle specific information, tells you what the code is in plain english, sometimes has a code assist function , and will usually do a live data stream

MS Fowler · #10 08-04-2013, 05:47 PM

Quote:

Originally Posted by kmaysob

Code reader-pulls generic codes. You then open a code book and see what that code means for your vehicle. A scanner pulls vehicle specific information, tells you what the code is in plain english, sometimes has a code assist function , and will usually do a live data stream

So the scanner is more convenient in use--but you pay a higher price. If I am able to look up a code in a book, I can get the same information from a simple scanner.
Is that close to right? I also understand that s given code doesn't necessarily mean that the part listed in the code book is faulty; it could be a bad connection, or a broken wire in that circuit. (and neither tool can tell you that.) Am I right so far?

kmaysob · #11 08-04-2013, 07:29 PM

Quote:

Originally Posted by MS Fowler

So the scanner is more convenient in use--but you pay a higher price. If I am able to look up a code in a book, I can get the same information from a simple scanner.
Is that close to right? I also understand that s given code doesn't necessarily mean that the part listed in the code book is faulty; it could be a bad connection, or a broken wire in that circuit. (and neither tool can tell you that.) Am I right so far?

kinda. the same code can mean 5 different things based on the manufacturer. in my opinion the scanner is the only way to go.

a good example would be a code saying random misfire. with a scanner, you can look at the data stream and see what cylinders are actually misfiring. on a recent vehicle i worked on, it had a random misfire that turned out to be 3&4. tracked it down to faulty plugwires. i could go on and on.

the nice thing with the pricier scanners is the code-fix function. basically shows you a list of frequently reported fixes. awesome for that one that completely stumps you.

aklim · #12 08-04-2013, 11:04 PM

Quote:

Originally Posted by MS Fowler

What is the difference between a code reader and a scanner? I think the terms are often used interchangeably.
Alkim--on pre-96 cars there was a way to read the codes. Ford used an analog multimeter and you counted the "sweeps" of the needle. But in 1996, with the advent of OBDII, they all use a common architecture, and codes. I suppose that is an improvement.

I would say that the code reader gives you a code. Say A P1211. It might tell you what the manufacturer (For instance Ford) says it is. P1211:= ICP Not controllable- pressure above/below desired.

A scanner to me gives you specific information. Say on my Vette, my scanner would read DTC-22: Throttle position sensor error (signal low). Also when I switch to scan mode, I can read what the ECM sees so it might tell me that the TPS voltage is 0.24V which is too low. HOWEVER, I can also depress the pedal slowly and see that the voltage goes up to 2.4V and then drops to 0V which indicates a bad spot in the TPS.