Full System Code Reader?

Gdetrailer wrote:

ktmrfs wrote:

Gdetrailer wrote:

Wayne Dohnal wrote:
It really does depend on the specific vehicle. Using my Sprinter chassis as an example, there are "zillions" of codes from every computer in the vehicle that can be accessed via the OBD port, but Mercedes has done an effective job of keeping the chassis-specific codes a secret. There are only a few several thousand $ devices that can read the proprietary codes. You'd probably have better luck on a forum dedicated to the chassis type, rather than an RV forum.

X2

Most aftermarket OBD readers have very limited amount of codes they are able to "read". Most of those codes which CAN be read will be for the ENGINE ONLY.

OBDII ports do have ALL codes available but they do not typically release what all the codes mean.

Reading any other codes including transmission and body codes WILL require a very, very expensive reader from the manufacturer of the vehicle.

Your best bet is to take to your vehicle manufacturers dealer, pay the ransom money to have them hook it up to your vehicle ($100-$200?)..

THE DEALER is the ONLY reliable way of getting the body codes read CORRECTLY.

while I do agree than many "generic" code readers limit the readout to ECM stuff, reading other stuff may or may not be difficult. I've queried many non ecm related codes on my silverado, including many transmission and BCM codes as well, Things like fuel level and any transmission status info as well. and on my mercedes I can get virtually all the codes through the obdII port with simple available SW. That includes things like checking the headrest motors, door lock functions, seat position, seat heater operation, all the AC codes including reading AC pressure.

And alldata often has a very comprehensive and extensive list of codes, not just ECM but body, transmission, etc. along with the recomended diagnostic tree if you need to decipher codes.

However, resetting safety related codes, such as air bag can be very very difficult to do. As you might expect, from a liability standpoint the mfg don't want things like that to be reset without verifying that whatever cause the code to be set is fixed and there are no related issues.

For example on my mercedes, I can easily reset virtually all the codes, except a few "safety" ones, like the airbag. that takes a unique tool to reset.

That IS why it is OFTEN BETTER just to go to the dealer in the FIRST PLACE.

Even if you are able to pull and read the codes, not all codes are the same or result in the same repair. ONLY the manufacturer knows for sure.

As far as resetting codes, there are many that simply can not be reset without the OEM "tools" and it varies from manufacturer to manufacturer and even then from day to day of manufacture.

Some codes do not need reset, just need a certain amount of "cycles" once the bad part is replaced or the trouble has corrected its self (many emission related codes will turn the CEL off after several successful drive cycles once the sensor is back in operating parameters).

The OP has a Airbag fault, this can caused by errors with the airbags, crash sensors, computer, faulty USED replacement bags (yep, folks DO resell BAD used airbags which had been fired and repacked) or even a bad (or wrong) airbag light on the dash.

With the complexity of todays vehicle airbag systems (my newest vehicle has not only front airbags but side bags in the seats and airbag side curtains in the roof, all told six airbags that would be a lot of money and time to find a bad one) sometimes it is cheaper, quicker just to pay the dough at the dealer...

If your comfortable going to a dealer, fine, but the dealer is certainly NOT the only alternative. The mfg isn't the "only one that knows for sure". Show me a code that you can read out that doesn't show up in alldata for the specific vehicle configuration along with the mfgs diagonstic tree. There may be a very few, but the vast vast majority are public. And any good independent shop has access to the same information, and in most cases the same diagnostic tools and SW the dealer has access to.

I've had codes thrown in cars since the check engine light first showed up in cars in the 80's. I've never had an occasion where I wasn't able to easily pull up the fault code(s), determine what the fault indicator was for, find a diagnostic tree for isolating the fault, fix the problem and clear the code and not have the code reappear. Yes,there are cases where the code won't clear till a specific drive cycle occurs without a failure. And there are airbag and a maybe a few other safety related codes that may take a trip to the dealer or repair shop to clear after the fault has been fixed.

And in every case, the fault code and diagnostic tree quickly isolated the fault to a very specific part in the system.

Never once have had to go to a dealer.