builtcb7

Hello and thanks for taking the time to read this. Please forgive me but I've been looking for a few hours and I can't find the topic on my issue. I thought I saw it so I figured if I start a new thread someone can point me in the rite direction.

I have a 92 accord. Yesterday I was driving on the highway at 85mph and the car just started downshifting on me. Thought I was going to die but thank God no one was behind me. CEL has been on for a while but never did anything about it cause the car was running fine. I pulled the code and it only gave me code 12. EGR. I just replaced it so I can get it to finally turn off knowing it has nothing to do with shifting. I've had the car 9 years and the D4 light never came on. Still doesn't. I've always change the trans oil once a year with dex 3. I replaced the TCU and it ran great for about 10 minutes then did the same thing. I think it's because I had the battery disconnected for a long while. Donó. If I remove the TCU all together the car runs fine only from 2nd to 4th with no bucking at all. When I hook it back up it goes threw all gears but seams to want to downshift almost threw all gears. I removed both solenoids and all click when put to 12 volts. I can't get the D4 light to come on at all and also now when in park I hear clicking from the shifter. This never happened before. I step on the brake and the clicking stops. Please help and sorry again if I'm in the wrong place for this question. Thanks again.

somick

Did you just replace the EGR solenoid or did you clear the EGR passages as well?

Good luck,
Sam

builtcb7

Yes. I took it off cleaned it. It was getting stuck so I soaked it with pb blaster and it's all good. No CEL.

holmesnmanny

I don't know why everyone has this sick obsession with Dextron 3. Nothing will ever work better than Honda transmission fluid, whether automatic or manual.

Be that as it may, it's not likely the code 12 is the cause of your shifting issues but you can clean out the passages and see if it helps since the D4 light isn't coming on to help narrow down the issue. You can't just clean out the egr valve, you have to clean the passages as well. Since the ecu wasn't seeing lift on the egr valve it was throwing the code and since the egr valve was so caked up it's guaranteed the ports are clogged up too.

https://honda-tech.com/forums/honda-...d-faq-1664547/

It actually looks like the link to the cleaning page is down so I found another video on youtube.

builtcb7

thanks. I didn't do everything in the video. I don't have compressed air available to me rite now but I do have everything else. I'll try all thus in the morning.

I only use tge dex 3 cause that's what they have at auto zone. Maybe I'll start using the Honda fluids from now on.

MAD_MIKE

If the D4 lamp is no longer functioning you will need to replace that lamp or at least borrow '1' or '2' lamp so you can get the diagnostic codes from the TCU(D4 lamp).

I would recheck your work by the EGR valve. On the 90-93s there is a ground wire that attaches to the thermostat housing, if these are loose/corroded/broken you may have issues with the correct voltage signal to the ECU. Engine functionality/driveability will greatly affect how the transmission shifts. On that note, start back probing the various sensors, TPS, MAP, ECT to verify that they are properly grounded, have a proper ECU reference voltage(5V) and are sending out expected signal voltage back to the ECU. A common problem is the TPS will have a break in the trace, this open or incorrect voltage signal, will cause no upshift or an unexpected downshift. TPS can fault out, you may get 1-4 gear shift when at WOT but as soon as the pedal returns to its normal angle of cruise(where the break in teh circuit would most likely be) the trans downshifts back to 1st.

Since your Interlock is clicking, there may be a short in the wiring to the gear selector switch, or the switch itself may be faulty or dirty. This would also command a downshift or erratic shifting. If the TCU thinks you commanded a downshift via the switch shorting to a gear that was not selected, then that would also cause the downshift. If you have spilled anything near or on the console recently, take it apart and verify the switch is clean and no damage to the harness.

The transmission will shift 2 to 4 on its own when there is a fault in the system. There will be no lockup and this is a limp mode function.

Get that D4 lamp working first. If a code is present from the D4 lamp, post back here for further diagnostics.