i have a '91 accord automatic and i think the ecm went out about two months ago because the sport light used to just flash all the time but then something happened when i was driving on the interstate and it downshifted and wouldnt shift up, i drove it home and parked it, i thought the transmission went out but i drove it about a week later and it worked fine after about an hour it did it again, i did some research and found out they have a bad problem with the tranny ecms messing up so i went and got another one from a junkyard, car has been driving fine for about a month now, until yesterday it did it again, could it be something else i am lost dont really know much about the accords or auto trannys lol i am a civic man and i like a 5 speed

 

help

 

Your TCM (Transmission Control Module) has most likely turned to toast. The flashing "Sport" light and the lack of an upshift are hints. These things fail with some regularity, so it wouldn't be much of a stretch that your second one went 'postal" too. The only other thing which comes to mind might involve the throttle pressure valve in the tranny. Although it often will not set a code (Flash the lamp) if either it or the cable that controls it should stick, it will keep the transmission from upshifting
There may well be a sticky thread in the FAQ section at the top of page 1 of this forum which deals with this condition.

These things are often found on EBay for cheap. It may be an option.

P

 

Sorry I dont have things to memory but if you have two ECUs, one for the engine and one for the tranny, then just disconnect the one for the tranny and drive the car like a manual, if it goes through all the gears except maybe OD, then the tranny itself should be good, give it a try and let us know.

I am also guessing that the speedo is working good???

 

yeah ok i have done a little bit more research into the search part of this website and found out a little bit. i have had the car for about a year when i bought it the sport light was flashing and the speedometer didnt work either, but the speedometer comes and goes sometimes it works and sometimes it dont but i didnt know that meant there was a problem, anyways as i said earlier a couple months ago we were just driving down the interstate when it just downshifted for no reason, before i put this second ecu in this problem would come and go, if the sport light wasnt flashing the car would drive like crap, it seems like it would take off in third, i could move it down into firrst and it would drive fine,shift up manually till i got to d4 and then it would just stay in third no matter how high the rpms got, as i said i swapped the ecu and it has been driving fine other than the sport light flashing and no speedometer ( i wasnt worried about the speedometer cause i thought it was a lose wire or something, was going to fix it later) my wife was driving it the other day and said that it wouldnt shift out of first and she had got all the way to like 4000 rpms, and said it was making some clicking noises underneath the dash, so i went to pick it up, i got there un hooked the battery for like ten mins and started it up and everything was normal, sport light was flashing and no noises from the dash, but now when i start it up and drive it the sport light isnt on and the speedo is stuck on 10 mph after like 500ft of driving the sport light starts flashing again and after about 10 mins of driving the check engine comes on, it drives fine well it seems like it shifts kinda high to be driving normal but it goes through all four gears(well as of right now) i am going to keep on driving it, but thats all i know and i have no clue what it is or what it could be so any help is great thanks

 

i would seriously suspect the Vehicle Speed Sensor which is mounted on the trans case. This unit fails and it will effect;
a) Speedometer
b) ECM (sets a CEL, and the subsiquent DTC)
c) TCM (Flashes the Sport / D4 lamp)

...sound like what you've got

P

 

ok thanks i will try and get another one

 

Please let us know how it turned out. I like to keep track of the people and their "issues"

P

 

Well before you buy a AT Control module (or tranny computer),

1- Pull the carpet at the passanger side bottom.
2- There should be a metal square, its the frame that hold the ECU and the ATC.
3- Unscrew it and remove . Usually it uses 10mm bolts.
4- Inspect the ATC by opening(unscrew the little 4 bolts on it, 2 each side)
5- Look for blown resistor or burn sections in the board. if there is a burn mark or a blown resistor, replace

Another chek is to pull the carpet and turn the key until ON position. Look at the computers and a red led should go on. If no red led light is present then no electricity is flowing to the part, wich means blown resistors in the ATC unit.

ATC = Automatic control unit or automatic transmission computer
ECU= Engine Control Unit

Also, having slow acceleration and the tranny not shifting means ATC is out too.

Hope it helps and please people, correct me if i am wrong im just a newbie trying to help

 

well the red light comes on and is blinking but as of yet i havent been able to go to a junkyard so i am still driving it i havent had any problems other than no speedometer and the flashing sportlight it comes on after like thirty seconds once you start driving

 

ur tranny computer is bad...open it and try to make a visual inspection of it to confirm. I got mines from junk-yard for 45 with core charge cause i kept mines to repair it. Be aware that to find accord tranny computer is difficult and may require like 4 different visits to different junk-yards since people take them out to sell in ebay (i know somebody who does)

 

pull trans code before going any further.

here is tcu code list:

1-Lock-up solenoid 'A' circuit open or shorted.
2-Lock-up solenoid 'B' circuit open or shorted.
3-Throttle Position Sensor circuit open or shorted.
4-Vehicle Speed Sensor open or shorted - No signal from speedometer.
5-Shift Lever Position Switch circuit shorted.
6-Shift Lever Position Switch circuit open.
7-Shift Solenoid 'A' circuit open or shorted.
8-Shift Solenoid 'B' circuit open or shorted.
9-Counter shaft or transmission speed pulse generator open or shorted.
10-Coolant Temperature Sensor open or shorted.
11-Engine RPM (Ignition coil signal) open or shorted.
12-(No code 12 used)
13-Main shaft speed pulse generator open or shorted.
14-Linear (line pressure control) solenoid open or shorted.
15-Kick down switch circuit shorted.

you will watch for blinks of d4 or sport(not sure on 9091)

also let us know if you have e codes.

 

you cant be certain just because it flashes bud.

flash could mean you are low on fluid, or any of the things that i listed in post above.

best bet is to pull code and go from there

 

hi I have a 91 Honda accord lx that I bought about a year ago the guy that sold it to me said that the timing was off and it was obvious that he had replaced a few parts on the vehicle, I found out that the head gasket was cracked and the timing was a little off I've gotten that fixed but still have a problem with the tranny I'm assuming. The sport light stays on constantly even when you push the little button on the shifter, sometimes when you hit the brakes it will get dimmer or go off, also when I use my turn signals the sport light flashes with them, the car has no HP in d3 or d4 so I have to take off in 2nd and then shift up after i get going, I'm pretty sure it also not shifting into overdrive because when i'm doing about 70mph my rpm gauge is reading around 4,000 and it never shifts, i'm not sure if this is a current problem or if it's from the head gasket being messed up but I also have oil in my coolant resivour. I dont know what to do I'm affraid the car is gonna blow up on me any help would be very much appreciated. Thanks

 

does anyone know what type of atc unit to put in a 1991 honda accord lx wagon? are they interchangable? please help me out

 

well, I will post a link to the thread I just made about my car a 1991 that has had the S light flashing prob for a while now. It seems like some of the simptoms differ a bit but in general, the tranny shifting is often affected, as is mine. Mine will not upshift by itself, and I think its missing 5th gear. It too must go up to 4k RPMs on the higway (or somewhere around that). Read my thread for more info.

 

https://honda-tech.com/forums/honda-accord-1990-2002-2/anyone-ever-heard-s-light-flashing-gremlin-2569935/

 

I was looking for some kind of blinking light on this computer board and I see no light flashing anywhere, where should I b looking?????????

 

one thing i want to caution you about, the junk yards will sell you a ycu, they think 1990 to 93 are all the same , they are not, they sold me one off a 90, 91 would not work also the dx and lx are generally the same but ex and se, are different and will not work, i also found that some have a super ceded number on them , best bet is to be sure the unit comes from the same year model. also some rebuilt units are also bad, after 5 of them i finally got one that worked right, so dont let em tell you they are the same. i know the numbers that fit the 92-93 lx and se but not the 90 91
Frank Allen
92 accord

 

one more thing, you might want to check with honda, they may be able to help.
Frank Allen