HelpYouHelpMe

Hi there!

I own a 1991 Honda Accord that has about 230,000 miles on the road. I take good care of it but unfortunately it started to have shifting problems about 3 weeks ago when the "S" light started to constantly blink every time I started it up...
I found out that that meant there is some kind of electrical problem and not a mechanical one, which brought some relief, but I totally still want this fixed like any person would.

Specifically, the car seems to only want to use two gears, but I can only change the gears using the T-bar manually to shift. Putting it in D3 or D4 makes the car stay in 3rd gear no matter what it seems, while shifting to 1 or 2 seems to keep it in 2nd gear...
I should add that sometimes (like 20% of the time) the "S" light never turns on or blinks when I start the car up, and it runs normally with no apparent problems.

To make a long story short, and to get to the main point, I eventually used the blue 2-pin connector to try and figure out the specific problem myself. I got as far as writing down all the wonderful codes it threw at me and wondering what each number meant.
I concluded there are a total of 6 codes after staring at the pretty blinking green light long enough, which were codes [ 1 , 2 , 5 , 7 , 8 , and 14]

Now I simply want to ask if anyone has advice as to what I should do?
A friend of mine has the exact same car and had the same "S" light blinking problem... and apparently he fixed it by replacing the TCU (Transmission Control Unit).
Is this what I should do? Or are these codes telling me that there are more things I should be worried about? I don't really know what each code means...
Any thoughts would be greatly appreciated.

Thanks in advanced!

ilikehonda

when my s was blinking i needed a new tcu. i had it rebuilt for 100 bucks

HelpYouHelpMe

Well before I make the decision to actually get a new one or get it rebuilt, I'm trying to make sure that these codes I'm getting aren't going to cause the "S" light to still blink or turn on even if I get a new TCU. Thanks for your reply.

ilikehonda

Code1 Heated oxygen sensor A
Code 2 Oxygen content B
Code 3 and 5 Manifold Absolute Pressure
Code 7 Throttle position sensor
Code 8 Top dead center sensor
Code 14 Idle air control valve or bad ECM

according to those your o2 sensor, tps, map, tdc and iacv sensors are bad or not connected correctly

i would reset you ecu by disconecting the battery for a bit then recconect start take it for a drive and pull the codes again.

djkaos23

Im having the same problem. can you put each problem with the code like code 02 is for o2 sensor etc.. I need this info like asap if possible.

cctgene

For what it's worth, you might check out the following site:
http://techauto.awardspace.com/transmission.html

ilikehonda

google search error codes...you will find them

HondaPartsHero

He's pulling transmission codes not engine sensor codes, here ya go

1-This Relates to Lock-up control solenoid (A) or solenoid circuit fault.
2-This Relates to Lock-up control solenoid (B) or solenoid circuit fault.
5-This Relates to Gear position switch or switch circuit fault.
7-This Relates to Shift control solenoid A or solenoid circuit fault.
8-This Relates to Shift control solenoid B or solenoid circuit fault.
14-This Relates to FAS wiring (Brn/Wht) circuit fault, between D16 and ECU

jerbut

I've had this problem for years, that is the "S" light issue and transmission problem. I discovered (accidentally) that replacing the battery solved this problem. Sounds strange I know. I was about to replace the computer at about $350. The car needed a new battery because it was old and not holding a charge. After I replaced it, the "S" problem went away after driving for about a half hour. If you think this may be a fluke, think again. I've done this twice during the life of the car and twice it worked. Worth checking out.

justinsbg

Always start by checking your battery and charging system before proceeding with any weird electrical problems. For those shift solenoid codes I would run the car for about 15 minutes, and ohm test the shift solenoids on the front of the transmission. Ohm testing is better done when the component being tested has been "working". A lot of times the solenoids fail which then burns some circuitry in the TCU (transmission control module). If you've diagnosed the solenoids to have too much resistance replace those first, then get your TCU rebuilt or the problem will return. I'm a one man electronics repair operation in NC, send your TCU to me and ill repair it for $80. If you need specs for testing let me know. Hope that helps a bit.

1991EX

I had the exact same symptoms on my 91 EX. Changed the TCU and everything was fine.

MAD_MIKE

Replacing the battery doesn't mean much. It simply could be that the codes were cleared and you have yet to reproduce the condition that causes the fault to occur. There is most likely an issue that needs to be resolved.

http://techauto.awardspace.com/transmission.html

esmzoso

Hello.

I agree with jerbut.

For what it's worth, here is my take. Please note that I am not an expert, just a guy with a lot of "clunkers" that I work on for friends and family.

I have had intermittent problems with my 1990 Accord [235,000] and I discovered they sometimes involved the post clamps on my battery being worn out. It took me a while to figure it out, too.

Make sure the battery is fully charged and getting a good connection before dumping any money into new parts. I always unhook the battery overnight to clear codes so the computer can re-dump the codes; you know to make sure that they are legitimate. It seems that sometimes a weak battery can send computer sending units into a frenzy.

Also, to add to Justinsbg post:
Another thing is what I call "cascading error codes." I've noticed that when I get a grouping of error codes, that one bad part sometimes leads to another. The first part is bad, after replacing it, the other codes drop out.

Like I said in the beginning, just some things to think about from a hack who has very little money to throw at parts.

esmzoso

Clancy

Mine (91 Accord wagon, 220K miles) seems to be just the opposite of what some have described. Worked fine until I had to replace an old, tired battery. As soon as I put a new, fresh battery in, I started getting the error codes. 1,2,3,5,6,7,8,14. Have disconnected the battery overnight several times to no avail. One morning, after sitting unused for a week, and about 20 degree cooler temp. than normal, it ran fine (no flashing "S" light.) That afternoon, back to normal air temp, it was back to flashing "S".
It seems that some folks are adamant that the TCU should be replaced. In other places I've seen pretty strong comments that the sensors should be replaced.

I just removed the TCU and took a look inside. Just a visual inspection, but the "usual suspect" resistors do not appear to be discolored or burned, and the capacitor looks fine - no oozing.

BTW, the symptoms, besides the flashing light, are that it acts like a slipping clutch when starting in D3 or D4, so I have to start in 1 or 2 and shift up. No other problems.

pgregor19

PLease help anyone. I also had a blinking S and transmission went into safe mode.
I purchased a TCU replacement unit from Galaxy Parts and had it installed. For about 30 minutes everything returned to perfect and the transmission was shifting properly. After 30 min. it went unfortunately into Safe mode again and it is stuck in third gear. I have also occassionally problem with locked gear, either in P or in Reverse, the remedy for which was to disconnect battery but this works only temporarily. I sent back my TCU to have it rebuilt but am concerned that it will be burnt out again. Any advice would be greatly appreciated.

JONNY856

I have the same problem wit the S light i seen i had a wet carprt on passanger side would that have been the problem i need somr tips will highly apperciate it

jerbut

I've had this problem at least four times over the life of my 91 Honda. Here is the solution I came up with. The S light does indeed tell you that the TCU is faulty. The thing is, the chance that it is really faulty is pretty small. What is probably the problem is you need a new battery because the one in your car will not hold a full charge. Get a new battery and you will probably solve your problem like I have so many times. The battery gets drained over a long period of time from some short somewhere and eventually that causes the TCU to signal it is faulty which causes your transmission to screw up. New battery, and you are back in business. good luck.
Jerrbut

kid colt

This Thread helped me....By having the codes. It told me the problem was in the lower shift solenoid...I was going to replace them when I noticed...The connecxtion from the wiring harness to the solenoids was bad. There was a pin inside the connector that had broken off (on the Harness side.) I eliminated the connector and wired the solenoids strait to the harness. I could have been replacing parts for a long time if I haddn't seen that broken pin.
The code tells you where to look....then troubleshoot the problem area.

Cargame

After seeing that this blinking S light issue is common on these accords, I pulled my TCU on my 91 wagon and sure enough I had blown capacitors. I sent my control unit to "justinsbg" who replaced them just a few weeks ago. My S light is no longer blinking and the transmission seems to be shifting back to normal. I would recommend contacting him if you have any questions and send him pictures of the inside of the TCU.

bryan702

Hi, I have a 1991 Honda Accord SE and have had the "S" light blinking for about 2 years. I looked online and saw that most people are saying to replace the "TCU". After looking online and seeing the cost it has been a long wait, and its driving me crazy because it feels like I am running out of gas all the time. Also the speedometer works intermittently if that has anything to do with it. I can spend a little money right now and don’t want to waist it on the wrong part. Does anyone have any pictures on the location, I have already wasted money on a Haynes book thinking it would help but cant find anything in it that would help me. Any advice, my Accord is my transportation car so I need it working.

MAD_MIKE

Did you ever find out what code the TCU is storing?
If the speedometer is intermittently working that is usually attributed to the VSS. http://techauto.awardspace.com/vss.html

Did you ever look at the link posted above?