Easy Duzit

Hello All. Yes I'm new, and yes I really have spent hours (at least 6) searching all over the web for the answers I've gotten so far.

The car is a 92 Accord Ex coupe. The car starts and runs fine until I turn it off. Then it won't start again and the D4 light blinks. Only happens in hot weather. This has been a consistent issue even after replacing a bad trans last year, but has gotten worse lately. I've spent the time and researched this online, and found the likely causes for not starting in hot weather, are either the main relay (bad solder joints), or a bad transmission control unit ( TCM ). Since the D4 light is blinking, I'm leaning towards the tcm. But I wanted to check the error codes.
So I cleared the error codes by briefly removing the main fuse, then started it and drove it a few miles. Turned it off, waited 5 minutes, and tried to start it, and of course it didn't start, but the D4 light started blinking (which I expected). I shorted the service check connector, and checked the tcm diagnostic codes by counting the blinking D4 light. It gave me 4 separate error codes. 1, 2, 7, and 8.
So here's whats driving me crazy. The only error codes I can find listed anywhere, are for the ecu, NOT the tcm, and believe me, I have spent hours searching.

I'm pretty sure the ecu codes do not apply to codes given by the tcm, because that would mean, according to the codes I got:

1 O2A - Oxygen sensor #1
2 O2B - Oxygen sensor #2
7 TPS - throttle position sensor
8 TDC - top dead centre sensor

None of which is transmission related.
I mean, If these codes were correct, wouldn't the check engine light be on instead of the blinking D4 light?

As for the check engine light, which gives the ecu codes, it only comes on briefly when I start the car, which is normal, and has never come on while driving, and it never comes on when the car doesn't start from this problem. Only the D4 light blinks. So I know the codes are from the tcm not the ecu. If I clear the codes and then start the car, it will run perfect for hours at a time, until I turn it off and try to restart it.

So I need to know what the tcm diagnostic codes are, not the codes for the ecu. Help.....

As it stands, I'm getting ready to pull the tcm and swap it out, since that is a known problem in hot weather, and hopefully that's it. But I would still like to find the correct tcm codes. Any help or ideas here are greatly appreciated. Especially if you can give me the actual tcm codes that I've been going nuts trying to find. A full list (tcm codes) would be awesome, and would help a lot of people besides me.


Easy Duzit

little white crx

fuel main relay, my accord has done the same thing in the past for some reason when the relay doesnt click on the d4 light blinks

gmiee5

I had the exact same problem:

D4 blinks error codes 1 2 7 8
happens more often when it is hot.

It ended up being the Main relay

HondaPartsHero

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

helldriver88

honestly don't believe the flashing D4 is related to the car not starting in hot weather. BUT i will admit i could be wrong. the car not starting again IS deffinately the main relay. 90-97 Accords have such an issue with those damn things. i have had the flashing D4 issue in the past but never did solve the issue, i swapped for a 5spd lmao. does the car shift really hard?

gmiee5

that was the frustrating part about the problem.

I replaced the TCU with a rebuilt one and had the exact same error 1 2 7 8
I then sent it back and reinstalled the old one.

Out of frustration I followed the directions on this forum to re solder the main relay. When I opened it up sure enough there where 2 cold solder joints. sucked out the old solder and replaced it with new solder. problem salved.

it has been over a week. the weather has been in the 80's and 90's and my daughter uses the car for pizza delivery. it used to brake down almost every other delivery.Now it has run great with no problems. thanks for the help.

Easy Duzit

I know it's been a while since my op but it was the relay.
Pulled it out, took the cover off and you could see the bad solder joints. Some fresh solder and then stuffed it back under the dash. No problem in hot weather since.

LandHard

I've had the exact same problem on my '93 ex. Only my problem with the blinking d4 happened after an accident to the left front panel, which also caused the speedometer, odometer, trip meter, and cruise control to stop working. The cruise control was broken due to the impact of the accident, also a bunch of electrical problems happened immediately afterward (left turn signal, CEL, windshield wipers won't turn off) but the problem with it not starting in hot weather happened much later and is unrelated in my case.

I finally got the damage fixed last week and was hoping the shop could straighten out the electrical problems and get everything working again, but the guy couldn't find any broken wires or any visually noticeable problems down there, so its all still not working. Damnit, I wish I could figure out whats causing all this.

Easy Duzit

Sounds like you have a lot going on. Probably should start your own thread, then you'll get some responses.
Short of that, if the body work was covered by insurance, then the electrical should be covered also, as long it was from the same accident. Talk to your insurance agent. They can probably recommend a good electrical shop too.

Wickit

Yeah 90-93 accords EAT through Main Relays. That's always something you should have on hand. Glad you got it fixed though man!

Toby_Cat

Hey first time using the site but i've been having the EXACT same problem as this thread. When I first got the car it ran fine, but then it soon wouldn't start after turning it off shortly before (D4 would flash). Sometimes it wouldn't start in the morning either (Once turning on electricals and seeing D4 flash I knew it wouldn't start). If you gave it 10-30min it would start again. Looked like main relay, but get this, after finally replacing the main relay the car doesn't start at all. D4 flashes just turning on the electricals. The fuel pump kicks over, we put starter fluid in the air filter, we even took a look at ECU and ATCU Circuit boards...perfectly fine. The car sounds like it's trying to kick over but it just doesn't have something for it to start. We hooked up the diagnostic light, no check engine codes but D4 codes 1,2,3,7,8,14.

holmesnmanny

The D4 codes and it not starting are two different problems.

For the starting problems, if, when spraying starter fluid into the intake, it tries to start, then the issue is fuel related.

So try to start it and if it doesn't start, spray some starter fluid into the throttle body after removing the air intake and if it tries to start you know the issue is likely the main relay or the fuel pump.

LandHard

It could be the Ignition Control Module. That's what happened with my 93 accord after I replaced the main relay almost 2 years ago. I got the ICM for around $12 of ebay and its started fine ever since.