Problem with a "S" Code

[rob_cee]

Did you fix the shift lever position switch?

replaced it...also good a good tip saying to replace my main relay, well before i replace "s" light still was on, sure enough i replace it and light went off and started right up

[deevergote]

That main relay throwing a transmission code still baffles me... does anyone have an explanation for that?

[rob_cee]

That main relay throwing a transmission code still baffles me... does anyone have an explanation for that?

yea, confused me too, but still went for it and glad i did

[cloudasc]

I am glad you were able to get it figured out. Next time your in Houston you owe me a beer j/k.

As for why it causes an issue, when looking at the electrical diagram, the only correlation I see is they share a common ground.

[Bad_dude]

The first thing I did when I got my CB was to get new tires and an alignment. Then I replaced the dizzy o ring. After I replaced the o ring, the car would not start, it turns over but never starts. I was scared as a tow truck would cost a bit as I was more than 45 miles away from home. It was burning hot. Left my windows down and came back in 30 minutes and the car started right up. It happens again when I was at home before work. Lucky I always go to work at least 45 minutes early. You know SoCal traffic, you'll never know. My work was only 10 minutes away. Went online that night and every single search there was at least 10 pages on the main relay. Went to Ebay bought a used OEM one for $12, never happen again for over 4 years now.
However, I never had flashing S light. That happened when my speed sensor died. I shelled out $165 for an OEM part plus $35 for labor that time. Since then I do every thing myself except for the axle replacement. Couldn't get that big axle nut off.

[rob_cee]

I am glad you were able to get it figured out. Next time your in Houston you owe me a beer j/k.

As for why it causes an issue, when looking at the electrical diagram, the only correlation I see is they share a common ground.

[Ctgearhead]

OK guys got back to my car and ran the diagnostics check and got these codes:

1-Lock-up solenoid 'A' circuit open or shorted.

3-Throttle Position Sensor circuit open or shorted

7-Shift Solenoid 'A' circuit open or shorted

8-Shift Solenoid 'B' circuit open or shorted.

14-Linear (line pressure control) solenoid open or shorted.

Thanks for your help guys

[cloudasc]

OK guys got back to my car and ran the diagnostics check and got these codes:

1-Lock-up solenoid 'A' circuit open or shorted.

3-Throttle Position Sensor circuit open or shorted

7-Shift Solenoid 'A' circuit open or shorted

8-Shift Solenoid 'B' circuit open or shorted.

14-Linear (line pressure control) solenoid open or shorted.

Thanks for your help guys

If you got that many codes, your tcu is dead. Time to pull up the carpet on the passenger side, yank out your tcu, open it up and inspect it for leaking capacitors. Then follow the DIY: 90-93 Tcu Fix guide to repair your tcu. Even if you source another one from the junkyard, or another source, its not going to be very long before it fails, and it would benefit from capacitor replacement too.

[deevergote]

It's not guaranteed that the TCU is dead, but it's likely... especially if all this JUST began. It would be cheaper and easier to attempt to repair or replace the TCU though. Be sure to get one from your particular year and model to ensure it works properly.

[Ctgearhead]

Well took out TCU and checked the Circuit board and The Capacitors are fine, not leaking, bloated, or damaged in anyway. All Resistors seem to be in good order.
Unless its an Internal short in any of the boards components Im thinking its either the Solenoids themselves or the wiring that leads to them are causing the codes.

Ill be testing all components with a Volt meter to make sure











While I have it out might as well replace the Capacitors for preventive maintenance.

That video on the TCU Fix thread is very informative! But as a noob to Circuit board repair I assume that there is more involved than just cutting/pulling out the capacitors and just soldering the new ones in right? Will it require getting to the back of the board and removing the solder as well?

If I missed anything or misunderstood something I apologize.
also if needed Ill upload more photos.

[Ctgearhead]

Also as far as the Main relay and the car not starting, it has been starting right up since I got back. Weird but after I get the whole transmission problems sorted out Ill concentrate on the starting issue if it does (and most likely will) come back.

EDIT// Just tested all the capacitors with a volt meter and they are all healthy. I was only able to get the 1uF 50V Capacitor from Radio Shack. Will have to online order the rest.

[Ctgearhead]

It's not guaranteed that the TCU is dead, but it's likely... especially if all this JUST began.

This has been happening for quite a while even when My dad was still driving it. Just wished he got that checked out before I inherited it.


Put the TCU back in the car to test something.


Ok so The regulator in my alternator shorted from age (Alternator installed in 06)
and when I hooked up the battery it started smoking so I quickly disconnected the battery. Thankfully it was under a lifetime warranty got another one for free. Everything works fine and nothing was affected. Just was kinda scary seeing how the CB could have lit up in flames :O

Still getting the S Codes though but now there Both Lockup solenoids and both Shift solenoids are going off as well as the line pressure solenoid and the Throttle position one.

[deevergote]

Do you know anyone else with an automatic CB (90-91, specifically.) If so, see if you can borrow their TCU. That will answer the question as to whether or not it's the TCU, or if you really have to replace all those parts. The best part is, you won't be spending money until you KNOW what you need to replace!

[Bad_dude]

Hey,
Since you got codes for the solenoids, take those off test each of the solenoids. If capacitors tested good do not means they are all good with continuous current. Capacitors lose their charge ability over time. This is why when I repair computer power supplies, I put in a higher voltage rating to keep them lasting longer. Quite a few years ago, when Abit motherboards were having their capacitors issues, I increased the capacity on all of the caps and the board became stable and worked flawlessly. I got my caps off from Ebay. Try to get caps that have brands on them at least. Low ESR is good but not required on the TCU but is better. If you are increasing the capacity, do not go over twice the voltage than the original. More than twice the voltage will give you ripple effects which is really bad for computers but not sure about the TCU. However a TCU is a computer sorta, so watch for that.
Good luck.

[Ctgearhead]

Do you know anyone else with an automatic CB (90-91, specifically.) If so, see if you can borrow their TCU. That will answer the question as to whether or not it's the TCU, or if you really have to replace all those parts. The best part is, you won't be spending money until you KNOW what you need to replace!

Thanks for the great suggestion!

My neighbor has an LX but its a manual
There is a familly with nothing but accords down the street might be worth a shot.

Ill hit up my facebook to see if anyone else has one.