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I bought an inexpensive code reader ($50) from Walmart.com recently to figure out why the check engine light had gone on on my car. While it's not a top-end model, and I know that it can't give me ABS or tranny codes, it should be able to give me any engine codes that the PCM sets, shouldn't it? When I hooked it up to my car's data connector, I got 2 codes back: P0449 (Evaporative Emissions Vent Valve Solenoid Control Circuit Malfunction) and P0455 (Evaporative Emissions Gross Leak Detected). I had also gotten a message on the car's dash advising me to tighten my gas cap once, which I did (even though it didn't seem loose). I cleared the codes using the scanner, but the P0449 code comes back repeatedly. Researched the code online, think I understand what might be causing it, and took the car to a mechanic to have him fix the problem.
Mechanic pulls the codes using his own code reader, and comes back with 23 codes!! WTF? Several of them were duplicate codes, but there were codes related to the EVAP system, as well as codes saying the fuel mixture was too lean or too rich, codes about the O2 sensor, etc. From one problem which I thought would be relatively easy to fix, all of a sudden I've got all of these other problems, according to the mechanic I went to. I'm not sure what to believe, really. He wrote all of the codes that he supposedly pulled up on a piece of paper for me, but he did not pull the codes in front of me, so I don't have any idea if these 23 codes actually came from my car or not. Personally, I feel like he was maybe trying to build up the bill to make up for me not taking my car to his shop when I needed to replace the starter last week.
Can there really be that much of a difference between the code reader that I bought (which is made by a well-known company) and the one that the mechanic has? Although his is undoubtedly more expensive, mine should still be able to pull up any engine codes stored on the car's computer, shouldn't it?
Make and model of the reader? Make and model of the car? It does make a difference! Ok posters, correct me if wrong: 2008 and up are OBD II CAN and need a compatible reader, yes?
Make and model of the reader? Make and model of the car? It does make a difference! Ok posters, correct me if wrong: 2008 and up are OBD II CAN and need a compatible reader, yes?
The reader is an Equus (Innova) 3030. It is a CanOBD2 reader.
The car is a 2006 Chevy Monte Carlo, which does use the OBD II system.
Here is some info about the reader from the manufacturer's website:
Works on all 1996 and newer cars, light trucks, SUVs and minivans – Domestic and Import
Links to all OBD2 protocols including CAN to decode “Check Engine” light problems
Equus (Innova) 3030 isn't top of the line, but it's probably not a POS either. Possibly dealership scanner reveal a lot more. I've been told they can even software tweak a TSB (technical service bulletin) via their scan tools directly into the car's computer.
I would have him chase down the cause of the codes the Monte Carlo keeps throwing, and it's possible if the other codes found are legit, the may be associated with whatever's going on.
IMHO A mechanic, I thank not. Let google be your friend, search the codes you got and see if you can't solve it yourself. You'd be surprised how easy some of these fixes are.
So many variables, so little time....lol
Your car has at least, off the top of my head, six different comtrol modules, all offering different codes.
Engine
Transmission
Body
Drivers seat...yep, quite possibly.
AM/FM/Sat/Nav
HVAC
Tire pressure monitor
SRS
The list can go on and on. If he was sitting in the car with the door open, it set a code. Nothing detrimental, just letting the scan tool know that the door is open.
Car ever been wrecked? I worked on a Caddy one time that was full of codes. Come to find out the wiring harness had been pinched in a wreck.
Car ever been wrecked? I worked on a Caddy one time that was full of codes. Come to find out the wiring harness had been pinched in a wreck.
According to the Carfax report that I ran before buying the car, it has never been in an accident, but personally I think it has.
The Carfax showed that it was originally owned by an (unspecified) car rental company in FL. When I got the car, there was some paint overspray on one side of the car that I had to remove with a clay bar. The front bumper's paint doesn't quite match the hood the fenders (it looks darker to my eye, especially in certain light situations). Also, a few months after buying the car, one of the fog lights came out of the bumper after going through a car wash, making me think it wasn't properly re-installed after body work on the front bumper.
Oh, and I forgot another thing.... Like I said above, the Carfax said that it was originally titled in FL. It it had been in use by a car rental company in FL, wouldn't they just try to sell it locally (in FL) when they no longer wanted the car? Why would the car end up at an auto auction in PA, where it was then bought by the Chevy dealer in PA who I bought it from?
If there were actually 23 codes set by my car's computer which hadn't yet been cleared, wouldn't my check engine light have gone on a long time ago? With that many problems, it would seem to me like the CEL would have gone on before now, when the P0449 code came up with my scanner. I've been driving this car for 4 years, and the CEL never came on until just recently.
Did the mechanic mention how many cycles past these codes had been thrown? Your cars computer stores codes for a long time, and one thing the professional grade scanner do that the cheapies don't is go back several cycles to find past codes. So 23 codes is a possibility, but many of them are probably "phantom" codes thrown one time due to some minor glitch, and it's possible that the actual problem is causing multiple codes to be thrown.
Did the mechanic mention how many cycles past these codes had been thrown? Your cars computer stores codes for a long time, and one thing the professional grade scanner do that the cheapies don't is go back several cycles to find past codes. So 23 codes is a possibility, but many of them are probably "phantom" codes thrown one time due to some minor glitch, and it's possible that the actual problem is causing multiple codes to be thrown.
When I went back to the shop to pick up my car, the mechanic had gone out for something so I didn't speak with him. His wife does the office stuff there, and she gave me a written list of the codes that she says he had found on my car. They didn't say anything about how many cycles past the codes had been thrown, but I did notice that in the list of codes, there was also another number at the end of the description for some of the codes. For example, one code listed is:
P0132 O2 Signal High B151
What are these "B" numbers after the code description? Other codes have either B151, B152 or B1 after them.
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Forgot to ask this in my original post...
