94 SL2 Persistent problems...

23 and 26 say...

23: IAT Circuit - Temp out of range low

26: Quad driver output fault

If I'm reading the Chilton's right, the quad driver controls outputs like solenoids, relays and indicator lights. The quad driver appears to control: canister purge solenoid, egr solenoid, coolant fan relay, service engine soon light, upshift/shift to D2, coolant hot light, control relay and speedometer output.

Hope this gives you some insight - any chance you can take it to a Saturn Service tech (I'm most comfortable with them over a local mechanic)...

...let us know how you make out.

26: Quad driver output fault

Saturn wants $1,500+ to replace it. They didn't check anything under the hood, or looked for shorts or bad sensors or anything like that. First thing said: "We'll have to get a new computer in that there car". I was like: and how did you determine that the computer is the culprit? Dead silence and then... "would you like to make an appointment to bring it in and have it replaced? Should only cost about $1,500

Are they nuts!?!

Even though there are so many things that can cause this error code, that was their quick and easy diagnosis. What a crock...

I'm still betting that the key to the whole problem is in this statement right here:

About 2 months ago the SES light started coming on whenever I would be idle at a red light or something and the temperature gauge was at 3-4/16's. As soon as I'd start driving, the SES light would go off when I reached the speed of 25 - 30 mph.

Error code 23 is IAT circuit low - sensor needs to be replaced. This shouldn't be much of an issue.

Anybody have any thoughts?

When ever you have a quad driver fault code with an additional code, always repair the additional first.

99% of the time, once the additonal code is repaired, the quad driver code will also go away.

It has happened to me several times over the 12 years I have owned my '92 SL2.

James

4 controls/sensors on that engine probably should be replaced if not yet.

Intake Air Temp Sensor, Engine Coolant Temp Sensor, Canister Purge Valve, and EGR solenoid are the most common componets to go bad. All 4 items can be bought for less than $100 if you can install them yourself.

James

1995 and earlier use a temp sender and a temp sensor. The single wire temp sender connects to the instrument panel and the two wire temp sensor connects to the PCM. There are diagnostics a tech (or a backyard mechanic with a Chilton's) can do. I think I've read here in the newsgroup that the connector gets corroded too.

Good post - should have read yours before leaving mine...

Also, how realistic is it that the PCM can go bad? And can a person reprogram it without having to buy a new one? Any other thoughts on this?

Are there any good websites that get into detail on how to diagnose / test anything that might be causing error code 26? Verifying sensors, stuff like that. So far, I've found one that seems to be pretty helpful and since I'm sure there are people here that could use it, here's the link:

Btw, everybody here has been most helpful and I appreciate it. I'm gonna follows y'alls advice, but will look into more scenarios that people might have.

Thank you! :)

Indeed. On my 93 SL2, I was getting codes 26 (quad driver) and 32 (EGR valve) so I just replaced the EGR solenoid and EGR valve, and the code 26 disappeared. The original poster should do what James says before anything else:

Well, so far we found out that the ATS sensor was totally missing, so getting a new sensor took care of error 23. However, the air induction tube that sits at the very front is missing too. Shall we say that the previous mechanic that changed out the fan never put the air induction tube back on is a total moron? I called that shop and told them I want my air induction tube back even if they have to buy a new one from Saturn and to make sure that the previous mechanic never, ever works on our car again. They were apologetic and promised that they'll do as such.

Now, the new ATS sensor sits by the air filter container and the car still gives error 26 as before. Once the temp gauge gets to aprox. 3-4/16's and I come to an idle position, the SES light comes on. Once the cars moving and I get to 25-30mph the SES goes off. The only thing I can think of besides the very rare ocassion that the PCM is faulty, is that the ATS sensor is not placed in its proper position because the air induction tube is not there. What do you guys think?

OK. Still with the same problem. Error code 23 is now resolved so no biggie on that, but error 26 has persisted. We replaced the TPS sensor because my Haynes Saturn book said that it's what error code 26 would stand for. Switched it out and still have the same problem. One thing that I noticed while we replaced the TPS and tested it... because I had a crazy idea that the floor mats were getting in the way... underneath the floor mats, the floor boards were soaked on the drivers side and the passengers side. Worse on the passenger side. Now what the hell is up with that? The only thing I've heard on it is that it might be my heater coil... am still investigating this and trying to figures things out. Does anybody here want to instill some of their input?

Do you have a sun roof?

If so, your sunroof has drain lines that come down the windshield posts and drain somewhere aft of your wheel wells.

Those things get clogged periodically...dust, dirt, pine needles...and drain onto your floor boards instead.

easy fix on a '94. You pull the air dampers off each side of the dash board and...(it's been years since I did mine)...take off those side kick panels. The drain lines are small black rubber hoses behind those panels.

Good luck.

I don't remember all the code numbers, but the canister purge solenoid and EGR solenoid/valve are fairly cheap and usually give out around this point. Have they been replaced yet?

Tim.

I owned a 93 SL2 - than bought a 95. Hmm. Well, I'm no mechanic, and wouldn't trust my car (any car) to a "shade tree" mechanic. I deal with my Saturn dealer. Any problem I had was solved on the first go.

Jazzz