I am the owner of a 1991 Honda Accord LX. The vehicle has 183,000 miles on it.
Approximately 1 year ago I replaced the lock up control solenoid and shift
solenoid (purchased rebuilt on line) along with servicing the TCU unit due to the flashing "S" and "check engine" light. This cleared the problem. The car recently had (less than a year ago) the EGR ports cleaned along with the installation of a O2 sensor. All was well until a month ago when I started getting the flashing "S" and "check engine" light again.The car is slipping somewhat in first gear with the other gears operating normal. Here's the catch- If I run the car for 20 minutes until it is totally warm, shut it off, turn it back on the flashing "S" and "check engine" light will disappear and the car with run perfectly fine. OBD1 diagnostics show code 6 and 12. Thanks in advance for your help.

 

Does your D4 lamp work?
Does the D4 or S lamp blink after the CEL has blinked? If so record those codes as well. TCU has its own set of codes separate from the ECU.

I take it the codes you posted were from the check engine lamp. If so...

6 is for ECT sensor.
Verify the wiring to sensor is undamaged and connected to the sensor.(located under distributor bolted to the cylinder head).
Verify the sensor is within spec.

12 is for EGR valve lift insufficient.
Verify vacuum hose to the EGR valve is unbroken and supplying vacuum to the EGR valve.
Verify when throttle is opened the EGR valve begins to open, if not the diaphragm may be damged/leaking and will need to be replaced.

If the engine is not running correctly, out of tune or damaged sensors, the TCU will not operate the transmission correctly. This greatly affects how the transmission functions, fix the engine issues and the transmission should operate normally.

 

Hi Mike-

Thank you VERY MUCH for your reply!!!

Sal Giosa