My daughter has a 1992 Honda Accord DX :Auto Trans 2.2L 2156CC L4 FI and the problem I'm having is with the Transmission. The D4 light comes and goes out like normal when I initially turn the key. When I put the car into the D4 position NO D4 light on instrument panel. All other gears light when I move selector to there position. I've replaced the old ATU (28100-PX4-721-M1-3LX) with a used Honda redesigned 28100-PX4-922 and the D4 light still stays OFF. I took off and cleaned and verified the lockup control and shift solenoids. They measure about 16 ohms across their coils and I could here clicking when they have 12V applied. I took the car to a local mechanic and he said the transmission seems to be good and to give the car a couple of hundred miles so that the replaced ATU can learn the parameters. I also had him do a transmission flush which he used DEX III. I asked him about DEX III in this car and he said it would be fine. He also said don't worry about the D4 light being out. My questions are as follows:

1. Is the D4 light being off anything to worry about?
2. Does it take 200 miles or so for the ATU to acquire parameters and shift smoother and/or shift at the proper speeds?
3. Is DEX III ok for this car?
4. Do you think she could have a weak shift solenoid or a defective Gear Position Sender?
5. Have you seen this problem before? If so what was the fix?

Thank-you for your response!
rsmith777

 

1. Is the D4 light being off anything to worry about?
No, strictly an appearance or convenience issue.You know when it's in D4 by shift position on console.

2. Does it take 200 miles or so for the ATU to acquire parameters and shift smoother and/or shift at the proper speeds?
I don't know for certain, but am doubtful.

3. Is DEX III ok for this car?
I used Dex III, but shifted to Honda ATF after readiing so many glowing reports. Shift quality is what is supposedly affected by Honda ATF.

4. Do you think she could have a weak shift solenoid or a defective Gear Position Sender? No, you checked and they are working. The D4 light is likely a fault in wiring from console to gauge panel.

5. Have you seen this problem before? If so what was the fix?
What problem? Surely you must have more than D4 light not working!

good luck

 

Thank-you for your reply TexasHonda. The reason D4 could be a problem is that it’s what the TCU Flashes when there is a problem. When you short out the 2 pin diagnostic port under the glove box of the passenger’s side it sequences a code by illuminating D4. I get no codes. D4 bulb is good because it lights up initially upon turning the key. So if it were a wiring problem I would expect the D4 light to be completely OFF or ON. The car does have the following symptoms:

1. When the car shifts into 3rd the RPM goes all the way up to 3500. Seems like the car revs to high going from 2nd to 3rd.

2. Daughter says car seems to be using much more gas then before this problem occurred. Could be caused by symptom #1.

3. Shifts kind of rough. Did Honda ATF make a difference when you switched?

If yes, can I do a double or triple flush of the trans? Which by this I mean I would drain the pan, add fluid, drive the car and repeat 2 or 3 times. So in other words can I mix Honda ATF with DEX III?

Thank-you, rsmith777

 

Thank-you for your reply TexasHonda. The reason D4 could be a problem is that it’s what the TCU Flashes when there is a problem. When you short out the 2 pin diagnostic port under the glove box of the passenger’s side it sequences a code by illuminating D4. I get no codes. D4 bulb is good because it lights up initially upon turning the key. So if it were a wiring problem I would expect the D4 light to be completely OFF or ON. The car does have the following symptoms:

1. When the car shifts into 3rd the RPM goes all the way up to 3500. Seems like the car revs to high going from 2nd to 3rd.

2. Daughter says car seems to be using much more gas then before this problem occurred. Could be caused by symptom #1.

3. Shifts kind of rough. Did Honda ATF make a difference when you switched?

If yes, can I do a double or triple flush of the trans? Which by this I mean I would drain the pan, add fluid, drive the car and repeat 2 or 3 times. So in other words can I mix Honda ATF with DEX III?

Thank-you, rsmith777

 

When you jump the connector, does the D4 light come on?

 

Alright, we have some problems to address.

First, your Accord may have an alternate way to extract codes. Pull back passenger side foot well carpet to expose the ECU/TCU housing. Look at upper side near center. There may be a small glass window through which you can see an LED (when blinking). Turn keyswitch to On and LED will blink the codes. My recollection is that is not necessary to short the service check connector, but my 90 Accord manual implies you do have to short the service check connector..

Looking at the D4 light issue. The transmission wiring diagram indicates that power comes from the dimmer control to power the D4 light and ground path is established through either the console shift position switch or through the TCU to enable D4 flashing. There could be alternate explanations, but the wiring diagram suggests that a fault must exist between the D4 light on the gauge panel and branching of the Grn/Blk wire to the shift position switch and to TCU. The startup flash of D4 light must be enabled through an alternate ground path, but I don't know for certain.

If you don't have a wiring diagram, you should download one of the 90-93 Accord manuals via the Online Manuals links in DIY forum to help.

Flaring of rpm on shifts may be corrected by adjusting the trans throttle cable (slight reduction of slack). Again shop manual is essential. Cars can be driven for years w/ a rpm flare, as long as you let up on throttle slightly to allow shift.

Shift quality is too subjective. The shifts in these trans was abrupt when correctly working, but I did not think they were rough.

Maybe some codes have be masked by the D4 light issue. Hopefully the workaround is functional.

I did not notice any improvement in shifting by going to Honda ATF, but was not unhappy w/ shift quality w/ Dexron III.

Fuel mileage things to inspect or replace: O2 sensor may cause loss of fuel efficiency w/ age w/o causing CEL, brake drag (check caliper pins and pads), tire pressures (32), air filter, spark plugs, spark plug wires, distributor cap, rotor. Check injectors/fuel rail connections for possible oring (dried out) leaks. A leak here can be difficult to see, but smell and feel are helpful. Remove vacuum reference line from fuel pressure regulator and smell for gas and replace if gas smell indicates ruptured FPR diaphragm.

good luck

 

how does your tranny fluid look and smell? the honda tranny fluid is a high friction modifier. and is compatable with dex . but to get the full effect you should do the three changes drive the car awhile in between changes. might help on the shifting if its a sluggish vlv body but usually it the 3rd shift clutch pack. there is about 3 or 4 clutch plates and about 4 or 5 pressure plates. they wear and that is one of the symptoms. but it also can still be the shift solenoid . they get lazy. my 94 had a weak alternator and when I replaced it the one volt made a difference in the shifting . strange but true.

and what texas honda said "Flaring of rpm on shifts may be corrected by adjusting the trans throttle cable (slight reduction of slack). Again shop manual is essential. Cars can be driven for years w/ a rpm flare, as long as you let up on throttle slightly to allow shift.

 

Thank-you for all your replies.

TexasHonda, The newer TCU does have the LED you're talking about but it does not blink either, jumper or no jumper. (No Codes) I will check the trans throttle cable when I can get the car back. Thanks for the tips on the manuals they will be most helpful also. I'll post again in the next few days when I can get my daughters car back.

poorman212, No the D4 light never comes on after initial key turn and does not come on with jumper in place.

hobieslug45, Fluid just changed no burn. DEX III

Thanks again, rsmith777

 

Sorry, IMO something is not right. Bulb check the D4 light comes on? Jump the connector and the D4 light will not come on?

 

I also think that if your going to use something other than the honda z tranny fluid you should use mercon-v this fluid exceeds all the dex/merc specs. I use to use this fluid when the old honda fluid was made by mobile. really **** fluid and didn't help the reputation of honda trannys. got 300k on this tranny mostly on mercon then honda fluid. fist tranny went at 150k using the old honda fluid .