The auto-trans problem might be associated w/ the Trans Control Unit (TCU). In some models there were faults. Check for any TCU codes by shorting the Service Check Connector and reading the D4 light flashes. This may provide a clue to your problem, particularly if it's electrical in nature.

good luck

 

Thanks - downloaded a manual and will try and get codes and post back here - feeling slightly more optimistic now with the fault being a bit intermittent, hopefully not as bad as first feared

 

OK shorted plug and got the following blinks on dash D4:-

16 short, 1 long, 4 short, 1 long

then this just repeats over and over. Checked manual from diy section and cant figure this out, seems to bear no relation to chart there - unless multiple faults? Can anyone help please, thanks

 

You might be getting codes 7, 9, 14. There should be a 2-sec pause between 7 and 9. Make sure you're reading correctly.

Try resetting the TCU by pulling the BackUp fuse 39( 7.5A) and driving for a few minutes, then rechecking codes. Disable short before driving.

If codes are displayed other than the 1-15 codes in the manual, its an indication of faulty TCU, which was suspected. You may need to locate a replacement TCU from a salvage yard.

Post back what happens after the reset.

good luck

 

Ah Ok thanks again, thought I had cocked it up somehow:-), will try again tomorrow and take note of pauses and come back to you.

Thanks for all your help so far TexasHonda

 

Ok checked the fault codes properly this time and get the following:-

1 - lockup control solenoid
3 - TP sensor
8 - shift control solenoid
14 - open circuit between ECM and d16 terminal
15 - mainshaft speed sensor

I would think it is quite unlikely that all these faults are genuine so do you think its worth changing TCM module as the next step?

 

All these codes suggests perhaps a wiring harness fault; pinched or damaged somehow. Any major work been done recently that might have damaged wiring?

Sometimes DTC's can be inter-related. I would suggest trying to determine if the code 14 is correct and fixing that. Once that is corrected, reset TCU and see what codes appear. It may be different.

good luck

 

tried to get to the TCM and ECU to check for continuity but failed at first hurdle - could not undo the 4 bolts on cover, my sockets did not have enough reach to clear the protruding studs!!! Will have to buy a long reach socket to fit - anybody know what size these bolts are? looks to be about 10mm does that sound about right (japanese cars are mm yes?)

 

Most all retaining nuts inside the cab are 10mm socket size. Use an open-end wrench to confirm size on one of them.

good luck

 

Finally managed to get multimeter and locate TCM and ECU

Continuity is good between between ECM and d16 terminal on TCM (fault 14) so does this mean its a faulty TCM?