My newly acquired (yesterday) 92 Accord EX has all the symptoms of a faulty TCM, or Transmission Control Module (or Transmission Control UNIT).

It downshifts at cruise or highway speed for no apparent reason.
When it does this, the D4 light will either flicker, or do off altogether.
It intermittently (more often than not) takes off from a stop in 2nd gear.
It sometimes simply will not upshift into D4 at all.
It feels like the torque converter is locking and unlocking, which wreaks havoc on the car at 45mph or more.

When I checked the codes yesterday, I got a code 12 for the engine, but nothing at all from the D4 light???
Everything I have read on here and elsewhere points to the TCM anyway, and pretty much says to replace the TCM/TCU with a "new" one.

My question...
Should I get a refurbished one off of Ebay, which has a warranty and runs about $110 or so, or get a used one somewhere, possibly a local junkyard or even Ebay? A remanufactured one from Rock Auto is $148 plus a $63 core. Recently laid off so I need to spend wisely...hence the question.

My car also has a Code 12 for the EGR, yet the EGR valve seems to working normally when I did some of the diagnostic tests today...I can live with the CEL for now, but NOT the transmission craziness.

 

A defective TCM usually has some symptoms such as D4 Light stays on constant when service check connector is shorted. Also you may hear some clicking from Main Fuel Relay under dash.

Your problems may be hydraulic and much more difficult to repair.

A good first step is to check the trans throttle cable and adust per shop manual (throttle plate and trnss lever begin to move at same time). Download a shop manual from Online Manuals posted in DIY forum if you don't have one.

good luck

 

Thanks. FWIW, the D4 light does stay lit when the jumper is in the connector. I didn't realize that was something to look for?

Thanks for the tip about the online manual.

 

So...we took it deep down into the city last night to watch the Orioles whoop the Red Sox again and found that if I shifted manually that it starts in D1 shifts to D2 and then to D3 but if I manually shift to D4 then the car does the crazy downshift/upshift back and forth thing....but of I leave it in D3 it runs and drives fine.
According to the TCM's numbers the car has "Sport Shift"...whatever that is?
I am going to go ahead and order a "rebuilt" TCM off of eBay and hope that fixes it....

If not the car will be parted out and junked since I am not dumping a chunk of money into an $800 car...

So.....

Can anyone tell me if any eBay "rebuilt" TCM" is a better option than a known good USED one???

 

If it comes w/ a warranty for some period, it would be worth more, perhaps twice as much. If not, a used is better bet IMO.

FWIW, I've been stung only one time on a used part bought by mail. Part was for the incorrect vehicle. It wasn't worth even complaining about, since shipping charges exceeded part value. One of the good things about used parts, is even a mistake is no big deal.

When I first started buying things on ebay, I worried a bit, but paypal and ebay's oversight have eliminated most (not all) scam artist.

I've also found car-part.com to be a rich source of good used parts by mail. No warranty, but dirt cheap.

good luck

 

Thanks again for the replies. The rebuilt ones and the one or two used ones all have some sort of warranty, with the one rebuilt one having a one year warranty. Price is fairly close, so I guess the one with 1 year warranty is best option.

I've actually been buying and selling various car, truck and motorcycle parts on Ebay since 2000, so no real worry there. In fact, the only time I ever had an issue, was for a $13 item, lol. A Paypal claim settled it in a few weeks. Just being new to the Hondas, I wasn't sure if that was the best option or not.

On a side note, I see your location is Katy, Texas. Several years ago I worked part time at a local speed shop called Martel Brothers Racing Parts. It was 2 brothers...one living in Baltimore, and one in Katy. The one I worked for had a massive heart attack and died, then they moved entirely to Katy. Ever heard of them?

 

Yes, I've heard of the name and know the location. I've not had any business w/ them however.

good luck

 

If the number on the TCM indicates it's a sport-shift model, it could be the wrong TCM for the car. I don't think 92 Accords had the sport-shift. The 91 Accord did, and maybe previous years.

 

Interesting...the ebay listing showed my current tcu's number as having sport shift....I do know it "looked" like it had never been out of the car before but who knows?

 

I haven't ordered it yet though...guess I better do some research tomorrow before ordering