1991 Acura Integra S3 flashing constantly wont shift into 4

Hi 91integra_rs,

Retrieve the trouble code and let me know what it says.

RETRIEVING FAULT CODES

ATCU System Fault Codes
NOTE:
Always check LED light for stored fault codes, even if "S3" light is not blinking.

1. If fault code exists, "S3" light will blink when ignition is turned on. When ignition is turned off and then on again, "S3" light will not blink again for original fault code, but fault code will be stored in ATCU memory. Fault code will be displayed by LED light on ATCU whenever ignition is turned back on. If ATCU senses the original fault again, "S3" light will
blink to indicate the fault.

2. To retrieve fault code, access ATCU and note location of LED light on ATCU. See Fig. 9. The ATCU is located behind drivers side of instrument panel, above kickpanel.

3. Turn ignition on, and check if "S3" Slight and LED light are blinking. If light and LED light are blinking, go to Step 5. If "S3" light blinks, but LED light does not, check for defective No. 34 fuse (7.5 amp) in engine compartment fuse box.

4. If fuse is okay, check for open circuit in White/Yellow wire between No. 34 fuse and ATCU.

5. Count of blinks from LED light to obtain fault code. For example, if LED light blinks once, it indicates Fault Code No. 1. If LED light blinks 10 times, Fault Code No. 10 is indicated.