Were you able to do all of the diagnostics that the shop manual suggests? You won't have that test harness, so you will have to backprobe the connections for the TCU and ECU.

If everything tests ok, then substitute the TCU.

 

How did you check continuity? Did you disconnect both ends and checking. Attempting to backprobe w/ connectors in place can be misleading.

If you haven't already, I would reset TCU (BackUp Fuse for 15 secs) and make sure same code/s come back.

It is rare for ECU or TCU to be bad, so you want to be sure.

If you're sure, time to find a replacement TCU.

good luck

 

TexasHonda
To check continuity I removed both plugs and checked from the pins. I was that hoping that as the fault identified by TCM is not present it would mean faulty TCM as this would be an eay fix (and cheaper than new autobox). Will reconnect everything and reset fuse to check codes again as you suggest - if the same codes are present what would you suggest as next step?

PAhonda
By backprobing do you mean putting plugs back in place and trying to check voltages at back of plugs? If so I can imagine this would be very difficult to do, would you have to remove some insulation to do it? i cant see any other way to do it.

 

Your test procedure confirms wiring is OK, but you could still have a faulty connector (unlikely but possible), or more likely an internal fault in the TCU.

Do perform the reset and see what codes pop-up. Sometimes electronics can be fixed by a simple reset.

If circuit fault code returns, I would pull the TCU, and using a good magnifying glass look for a fault (shorted circuit or damaged component) on the TCU. Some have had success w/ repairing their TCU. Othewise, the salvage yard is next stop to find a compatible replacement.

good luck

 

Thanks for your help (again!) will do as you suggest

 

plugged everything back in (didnt have to reset as battery was completely flat so had to remove and charge overnight), now getting fault codes:-
1,3+8

seems like 14+15 have disappeared?

Is it worth just getting a TCU from scrapyard? Seems unlikely to have 3 seperate faults still on system and two of them disappearing

EDIT - removed cover and did a visual check of circuit board but no obvious problems seen

 

Are these ECU or TCU codes. I don't see any TCU code 38, or is this TCU code 1, 3, 8?

regards

 

Yes codes
1
3
8

 

I'm at work now, but will respond this evening after reading my shop manuals.

regards

 

Thanks very much - really appreciate all your help