I have a 1991 Honda Accord EX automatic. I purchased a p06 auto ecu and had the ecu chipped. When I start the vehicle, it runs fine but the "s" light flashes. When you drive the vehicle, you have to manually change the gears and it only has 2nd and drive. It doesn't do this with the stock ecu. I'm lost as to what the problem may be. Any help??

 

Your chipped P06 and the Accords TCU aren't working together as they should. The S light flashing is telling you there is a Transmission Control Unit (TCU) error code. You can use the paperclip method for retrieving these error codes. reading the codes will give you a better look into what is going on.

 

What should I do to resolve the problem.

 

Codes 1, 2, 3, 7, 8, 10, and 14

 

Since it's a civic ecu would I need to use a civic tcu to communicate with the civic ecu?

 

Who chipped it and what software did the use? Not a lot of people out there that tune automatic Honda's properly.

Some tuning software does not allow the use of automatic TCU tuning.

 

3- TPS
10- ECT
14-FAS

There is no communication between ECU and TCU.
If the ECM was chipped/programed with AT use in mind, then the data stream should still be there. But if the ECM is a Civic, then the wire terminals may be changed between Civic and Accord.
Verify the terminals are correct for the Accord TCU, if not switch the pins around to match. Civic TCU may be correct, but whomever programmed/chipped the ECU for AT usage should have informed you of any changes.

 

Ecu pins or tcu pins?

 

If I'm not mistaken the OBD1 Civic ECU has an onboard TCU. So that being said I would imaging that the wires will not be going to the proper locations without a conversion harness or swapping some pins on the ECU. I have never tuned an automatic Accord so I am not 100%.

But I do know the following ECU/TCU pin locations;

OBD1 Civic ECU output for A/T
ATLSA = A19 (direct to lock up cont. Sol. A)
ATLSB = A17 (direct to lock up cont. Sol. B)
ATNP = B7 (Neutral / Park indicator on shift pos indicator and console switch)
ATD3 = B3 (D3 indicator on shift pos indicator and console switch)
ATD4 = B4 (D4 indicator on shift pos indicator and console switch)
SLU = D18 (direct to interlock control unit)

OBD1 Accord ECU output for A/T (These all connect to the Accords separate TCU)
AFSA = B3 (to TCU)
AFSB = B4 (to TCU)
ATNP = B7 (Neutral / Park shift position indicator)
FAS = A18 (to TCU)
VREF = D18 (to TCU)

Pretty sure this is why the ECU is not communicating with the Accord TCU.

 

so what exactly do I need to swap? I read your above post but Im not exactly sure what to swap?

 

Sorry boss, like I mentioned above. I have never tuned an auto Accord with a P06.

I have read that some have plugged a P06 in and it ran fine. Not sure how that works but I have been seeing that it was using Uberdata 1.66 software. Not sure if that is even used anymore.

Might want to try looking through cb7tuner.com. There is a thread there that talks about tuning automatics. However it makes no mention of having to swap ECU pins????? Have an auto and want to run a chipped ecu? - CB7Tuner Forums

Wish I could be more of a help to you.