Having worked mostly on older vehicles, how important is it to get a decent OBD II scanner to start work on my 1998 SC2.

 

It's a great time saver.
By indicating problem in specific systems and sometimes even specific components you can focus your troubleshooting time more productively.
Of course, there are many problems that may occur that won't show up in a scanner but then you're no worse off then before you had a scanner.
An important point to keep in mind though is that the OBD II system doesn't cover every system on the car. ABS is typically a separate system and requires either a premium (read expen$ive) scanner upgrade or a separate specialized scanner.
For many vehicles the transmission also requires a separate scanner but thankfully not the S series Saturns.

Check out one of the many OBD II codes listing sites to get an idea of what all can be learned about a vehicle from a scanner.

 

Please note that there is a difference between a code reader and a code scanner. A code reader usually denotes a device that will read only the stored P codes (powertrain)

A code scanner will read additional types of codes from different parts of the car's systems.

B=Body Codes (Body Control Module)C=Chassis codes (airbag systemX=Communications Codes (between modules)

Then come the Manufacturer specific codes, For each category there may be additional codes defined by the manufacturer to have a specific meaning. Like a B1462 for a Saturn might be one thing, but Ford uses B1462 to mean something slightly different.

You usually do have to pay more for the ability to access these enhanced manufacturer specific codes.

One of the key things to remember is that only the P codes will eliminate the service engine soon light.

You may have 12 body codes but you do not know they are present unless you look for them with a device that can access them.

That said, a 98 SC2 does not have a body control module for which you are very thankful.

As mission before, these more full-featured scanners give you the ability to read rather specific information for the ABS system and SRS airbag system when one of those lights goes on and stays on. For example I believe airbag sensors show up as chassis codes when the impact sensors themselves are faulty or generally stop communicating with the airbag control module. It will literally tell you which sensors are not behaving properly as opposed to you having to play musical exchange a part to troubleshoot what is otherwise complicated because of how the sensors talk to the control module.

This is the reason that professional mechanics invest $$$ to be able to read and diagnose a zillion different types of cars. Their systems can talk to the PCMS and bcms and everything else I mentioned in generic OBD 2 language as well as query for manufacturer specific codes.

By law/std, the definitions of OBD2 codes are fixed for certain number sections of the p B C and X codes so that all cars have the same set of response codes for the same general issue.

The juicy stuff is in the manufacturer specific codes which can have any definition they want as assigned by the manufacturer..

In addition to just reading codes, you want to consider whether to get a scanner at can display real time data. The answer today, due to the decreased cost of capable scanners that can do this, is **** yes.

This is where the difference in scanner ability really shows up depending on what type of vehicle you have. A GM tech 2 tool is programmed to access all kinds of information from the PCMs specific to GM vehicles and some others as well. It is capable of displaying real-time data for many many many parameters that most scanners except the very high end scanners cannot. So there is a sliding scale of usefulness for this feature. Being able to to real time display data of basic information like air to fuel ratio, fuel trim, RPM, oxygen sensor voltage is helpful and available from pretty much all PCMS. However, obscure critical 14th order integrals associated with the map sensor on a 2027 Hayseed Model R is not terribly useful unless you work on them regularly.

So to make a short story longer which is my specialty, I would recommend you get a reasonably full featured scanner that can read generic OBD2 codes and, if not outrageously expensive, a scanner that specifically States it can read manufacturers codes that include your year of Saturn vehicle.

I say this because I have a very nice bluetooth-based scanner with great software for the manufacturers enhanced code scanning, but most of these newer scanners are not supplied with programming capable of pulling out lots of wonderful real-time information or even static information from the older OBD2 cars. Also known as your 1998 SC2 and my 1997 SC2. Yes the basics are there but it essentially doesn't pay for manufacturers of new devices to spend the time writing the routines to pull all these different pieces of information because people are worried about and want this ability for the newer cars and recently produced cars. This is where considering a slightly older scanner that is used or refurbished but 100% has the capability to interrogate the PCM for this additional information should be considered.

Continuing to elongate this discussion with myself, one can argue whether or not you really need to access every last bid of information that you theoretically can. The general answer to that is no unless you are a professional mechanic who works on older obdii Saturn's constantly.

In closing, it would be wonderful to have access to more information in real time for your 1998 Saturn SC2, but you can get by with no enhanced manufacturer code support. If for no other reason than you pretty much have to unless you are willing to spend a ton and for one car and the complexity of the mid 90s no BCM S cars it just doesn't make sense. If you have five GM vehicles in your driveway and do all your own diagnostics, and you some of your cars are newer, enhanced GM manufacturer defined code support will likely be worth it as those systems are more complicated, especially with how the body control module interfaces with everything else. So you need to step back from just your needs with the Saturn and consider your needs for your entire vehicle stable.

This droning endless opinionated rant brought to you by Derf, the mod that just won't shut up.

 

Gosh...... I had a response about half way through that read, but forgot what it was ...... first, thanks Janmar for your response. I do like being new to a forum and find there are folks willing to respond and help early on.
Derf, I did go out in my shop yesterday and found an OBDII scanner I forgot I had. I remember I bought it years ago when I built a 95 Chevy Z28 convertible. It is the basic orange model from diydiagnostics. I believe they changed the protocols shortly after that, or around that time, so I'm hopeful to try this one out. I believe the 98 sc2 used VPW protocol, I'm anxious to get the car up here to start working on it.

Thanks again for the responses.

 

95 was OBD I. 96 and up is obdii. Different communicatios protocol, diff connector, different pids, different different.

But if the scanner is designed to read both using an adapter cable it just might work.

 

Welcome!