No codes yet...still working on that. I just picked up the 2003 factory service manuals and all things "ABS" start with an ABS scan. My dealership indicated they would charge me $40 to hook my truck up to an ABS scanner to just get me the codes. At this point, unless some other solution pops up, that looks the way I will have to go to get the codes. There are no after market ABS scanners at this time.
There are, but they are incorporated into the higher end scan tools that cost thousand$. Snap-On Modus, Mac Mentor, and others have this capability.
__________________
Terry Change is inevitable, except from a vending machine
AIR#2611
...One thing I haven't seen yet is what were the codes the dealer pulled out of the ABS module?...
I had the ABS system scanned today and there was only one code: C0550.
Here's the lowdown on the code:
Condition:
Some customers may comment on a permanent illuminated ABS telltale lamp. When checking for DTCs with the diagnostic scan tool, you may encounter DTC C0550 stored in history.
Cause:
The HVAC blower motor, when the vehicle is keyed off, may generate sufficient electrical power during its coast down period to cause a false C0550 code to set in the ABS module. The generated power created by the blower motor is of a "dirty" erratic nature, which cannot be correctly interpreted by the ABS module.
Correction:
Reprogram the EBCM with the new service calibration, which was available from Techline starting April 14, 2003 on the T152000 version 4.0 or later. This calibration is an electronic calibration and is not available from GMSPO. DO NOT REPLACE the EBCM for this condition unless normal diagnosis identifies the module as the cause.
Good news. Nothing seriously wrong with the brakes. And your techs did a good job of backtracking thru the old TSBs.
It makes sense that a blower motor could backfeed a wave signature when winding down. I'm not at work this week so won't read the TSB, but I can guess that a funky body ground is behind this somewhere. These are the cause of numerous hair pulling, foul language and lost time.
GM is not alone with software updates. We just got 7 last week on the VW side for the '07s.
At least it's good to know that the TV's brakes are set for a while.
Reminds me, got to start poking in to that brake controller.........
What's KAN ? I also see reference to CAN (Canadian extensions to OBD-II?).
I'm late to this and apologize if nobody's interested any longer.
OBDII was originally (1996) legislated to work on an SAE datalink - J1850. This had three flavors, one each for Ford, GM, and Chrysler. GM & Chrysler used the same wiring scheme (10.2 kbps, 1 wire, vehicle ground) while Ford went with a somewhat faster 2 wire scheme, if I recall.
The next generation of automotive networks were CAN based - Controller Area Network, which although much faster, retains a stunning variety of available implementations. 2 wire, 3 wire, 250kbps, 500kbps, 1Mbps... you pick.
Anyway, at these data rates you can do a lot of things you just couldn't do with the older, slower, less expensive J1850 protocols - things like automated manual transmissions and radar-integrated cruise control, for example.
The smog police - not just here, but EURO too, allowed some existing high-layer protocols (including the spec that defines the "P" codes) to be glommed on to CAN based protocols.
Thus, a really useful scan tool will have to work with CAN.
I'm late to this and apologize if nobody's interested any longer...
Oh no, don't worry about that! Your comments are always welcome! I'm still shopping around for an after market OBD-II scanner so would still appreciate any feedback. This thread actually took a turn when I started to talk about why I needed the scanner and next thing you know I received lots of helpful suggestions from folks on my ABS issue.
I'm late to this and apologize if nobody's interested any longer.
OBDII was originally (1996) legislated to work on an SAE datalink - J1850. This had three flavors, one each for Ford, GM, and Chrysler. GM & Chrysler used the same wiring scheme (10.2 kbps, 1 wire, vehicle ground) while Ford went with a somewhat faster 2 wire scheme, if I recall.
I thought the point of OBDII was a consistent interface across all brands which included not only the physical connection and protocol but the codes as well? I know it still allows for "customization" but only as a "super set" of the basic requirements. In Washington State the required pollution inspection on OBDII vehicles relies entirely on the data from the OBDII interface. Older vehicles are tested using a dynonometer and an exhaust gas analyser.
Quote:
The next generation of automotive networks were CAN based - Controller Area Network, which although much faster, retains a stunning variety of available implementations.
Is CAN a standardized protocol (like Ethernet) or a combination of hardware implementation and software features? Does it use the same connector and include support for the required OBDII functionality? How much standardization is there with CAN among the different manufacturers?
...Older vehicles are tested using a dynonometer and an exhaust gas analyser...
Would you mind if I hijack my own thread to ask an unrelated question? In Massachusetts, the law mandates that every vehicle is inspected annually. On the odd years it is a safety inspection only and on the even years the inspection is a safety inspection and an emissions test.
I'm curious about why, for my 1990 Miata, I have to have the safety and the dynometer testing EVERY year?! Why wouldn't the dynometer get alternated yearly like computerized emission testing is for vehicles with OBD-II? Does anyone know why?
I'm curious about why, for my 1990 Miata, I have to have the safety and the dynometer testing EVERY year?! Why wouldn't the dynometer get alternated yearly like computerized emission testing is for vehicles with OBD-II? Does anyone know why?
Because the Miata, being older, is statistically more likely to require emmission repairs than a newer vehicle. Also, being pre-OBDII, it doesn't turn on the MIL when the emmissions levels are higher than they should be.
__________________
Terry Change is inevitable, except from a vending machine
AIR#2611
OBD II really is for emission control at the tightest levels above all else.
in the beginning in 93 -95 OBD I ,we were nervouse ,then came OBD II
and we were doomed .The restrictions on modifications and big brother
intereference and oh my !!! Well ,things turned out really better than we had thought .The vehicals are much cleaner than you can believe in emissions
levels ,the power of these engines are very very good . The computer PCM
is very reliable and sophisticated ,self diagnoses / sets codes to read for
diagnostic repairs .I really like to be able to plug in and check codes ,move
on to data stream ,look over all the great information at my fingertips on
the screen ,perform repairs ,then rescan the data to confirm the repairs
are done and complete .OBD-II really allows the vehicals to be worked on
by non mechanic folks who want to do there own work . The older vehicals
were limited to testing each sensor individually and no data stream on the
old scan tools .you can see all the sensors and there operating readings at
a look on the tool without opening the hood .The I M readiness is where
the smog station will scan the PCM for any codes and that all the Monitors
show READY and ,if not the car cannot be smogged unless these are READY.
I believe 2 Monitors can be NOT READY ,but not 3 . you then need to drive
the vehical (drive cycle) until the MONITORS show READY as needed .This
is a pain for people alot of times .smog your vehical sooner than later and
better not to wait to the last minute .Many times the technician can perform
a drive cycle to get the monitors to show READY ,but not always .Most
states will adopt the IM READINESS checks before a smog check will be done
in addition ,check engine MIL light on ? will not pass smog no matter what.
as the tech will not be able to run the test .A word on the blower motor
business ,the PCM reflash updates will fix it . But it should not be able to
interfere with the ABS in the first place .It sounds like a shielding problem
if the ABS PCM is picking up the blower motor intereference.
CAN was developed by Bosch. Has a couple of different flavors, and they are different. May be helpful to think of them as different dialects of a common language, but more like Spanish/Portuguese/Italian than English/Bahston/Aussie. I believe CAN does specify hardware to a certain extent, but it also has a great deal to say about the "overhead" bytes that help to convey the information. You have to get into a specific implementation of CAN before you can really nail down one wire spec, connector spec, etc.
The SAE specs, among which are the implementation details of OBD/CARB specs, are mostly living documents, with updates proposed by commitee members twice a year. Thus if Manufacturer X comes up with a new component that needs a P-Code, they'll petition the SAE for it a year or so in advance of product launch. Sometimes revisions are made to existing specs - corrections of typos, technical details, or further specifying something. The combination of these two activities means that new codes show up from time to time, and an older tool might not catch a new fault.
OBD regs cover three basic areas:
1) the amount of emissions that may be released
2) how and what must be monitored. Basically every actuator and sensor that's related to emissions must be monitored.
3) how to represent the information to a tool.
Actually, this is typical of emissions regs, including the EURO series, but the details vary. CARB are the most difficult, followed by EPA then EURO. Fortunately for us in the US, if you meet CARB, EPA certification is for all practical purposes automatic.
By far the easiest of these to design is #3, although as mentioned in an earlier post the rules about readiness, multi-trip faults, fault self clearing, etc. are both arcane and somewhat awkward.
It should be noted that anything I've typed is off the cuff and it is quite likely I've messed up on a detail or two, so don't lean too heavily on it. On the other hand, if you were curious about how the whole mess fits together, it may be somewhat useful.
It should be noted that anything I've typed is off the cuff and it is quite likely I've messed up on a detail or two, so don't lean too heavily on it. On the other hand, if you were curious about how the whole mess fits together, it may be somewhat useful.
So how does this shake out for the home mechanic?
If you just want basic information/codes to determine if something is abnormal and if it needs to be taken to a mechanic or might possibly be a home fix is a basic OBDII scanner all you need?
If you want info while driving (data stream?) does that require CAN or, depending again on how deep you want to get into it, would it be possilble to do this with a higher end OBDII scanner?
Are there a small number of cables/connectors for OBDII and CAN or do manufactureres all come up with their own and change them from year to year, model to model?
Is it worth buying a scanner with a dsiplay or does it make more sense to interface with a computer or PDA? Does this depend again on how deeply you want to dig into the repairs?
Bernie, '03 and newer is almost all CAN (or KAN). If you get a scanner, make sure it is CAN compatible if your vehicle is 2003 or newer, you don't want to buy something you can't use, and most places won't take back electronic items after they've been opened.
My Snap-On brick has a series of electronic "keys" to use with different manufacturers, and my OTC has plug-in cartridges for different years, but all makes for those years--foreign or domestic.
__________________
Terry Change is inevitable, except from a vending machine
AIR#2611
So how does this shake out for the home mechanic?
If you just want basic information/codes to determine if something is abnormal and if it needs to be taken to a mechanic or might possibly be a home fix is a basic OBDII scanner all you need?
If you want info while driving (data stream?) does that require CAN or, depending again on how deep you want to get into it, would it be possilble to do this with a higher end OBDII scanner?
Are there a small number of cables/connectors for OBDII and CAN or do manufactureres all come up with their own and change them from year to year, model to model?
Is it worth buying a scanner with a dsiplay or does it make more sense to interface with a computer or PDA? Does this depend again on how deeply you want to dig into the repairs?
Thanks,
-Bernie
I haven't given it much thought, but probably a generic tool would be just fine. One of the things the EPA has been driving is to make as much of the scan tool functions publicly available as possible. I haven't looked into the PDA/Laptop option, although if you already have one, it might be less expensive overall? I don't know.
I think generic tools will have the cable you need. The EPA did/does (?) specify the list of allowable connectors and their pinouts.
The data stream is most likely proprietary in a 3/4 ton or under truck. Even if it's non-proprietary, (e.g. j1939) reading it is tricky unless you have access to a message database (or build one). I don't recommend trying to read the raw hex messages in real time; it takes some practice and kind of freaks people out.
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