To pull the codes from your SR20DET ECU, follow these instructions...

1) Locate the screw hole on the side of your ECU.
2) Use a small flat head or philips head screw driver to turn it all the way counter clockwise which is diagnostic mode. Make sure you do not force the screw. It should turn very easily and will stop when it has been turned all of the way. It is maybe 1/2 -3/4 turn. Not much.
3) Make sure the ignition is on. The engine does not need to be running
4) Locate the red LED next to the screw hole on the ECU
5) Count the blinks. The long blinks with longer pauses in between represents the 10's and the short blinks with shorter pauses in between represents the 1's. I.E. 4 long blinks and 3 short blinks would be 43.
6) Document the codes. The ECU will cycle through all of the codes and then begin again.
7) When done return the ECU to normal operation mode.

Long Flash - 0.6 seconds on (the first digit)
Short Flash - 0.3 seconds on (the second digit)
Long Gap - 2.1 seconds off (used between codes)
Short Gap - 0.9 seconds off (used between digits)

The codes are as follows...
Code Meaning
11 - Camshaft Position Sensor
12 - Air Flow Meter
13 - Coolant Temperature Sensor
14 - Vehicle Speed Sensor
21 - Ignition Signal
25 - IACV - AAC Valve
26 - Boost Pressure Sensor
31 - ECM Fault
32 - Exhaust Gas Recirculation System
33 - Front EGO Sensor (O2-1 Sensor)
34 - Knock Sensor
35 - EGR Temperature Sensor
36 - EGR BPT Valve
37 - Closed Loop System
41 - Intake Air Temperature Sensor
43 - Throttle Position Sensor
54 - Signal from Auto Transmission
55 - Other Malfunction. CONSULT Terminal Required
63 - Cylinder 6 Misfire (?)
64 - Cylinder 5 Misfire (?)
65 - Cylinder 4 Misfire
66 - Cylinder 3 Misfire
67 - Cylinder 2 Misfire
68 - Cylinder 1 Misfire
71 - Random Misfire
72 - TW Catalyst System
76 - Fuel Injection System
77 - Rear EGO Sensor (O2-2)
82 - Crank Position Sensor
84 - Automatic Transmission Diagnostic Comms Line
95 - Crank Position Cog
98 - Coolant Temperature Sensor
103 - Park/Neutral Switch
105 - EGR Solenoid
111 - Inhibitor Switch
112 - Automatic Transmission Speed Sensor
113 - Automatic Transmission 1st Signal
114 - Automatic Transmission 2nd Signal
115 - Automatic Transmission 3rd Signal
116 - Automatic Transmission 4th Signal
118 - Automatic Transmission Shift Solenoid Valve A
121 - Automatic Transmission Shift Solenoid Valve B
123 - Automatic Transmission Overrun Clutch Solenoid Valve
124 - Automatic Transmission TOR Conv Solenoid Valve
125 - Automatic Transmission Line Pressure Solenoid
126 - Automatic Transmission Throttle Position Sensor
127 - Automatic Transmission Engine Speed Signal
128 - Automatic Transmission FluidTemperature Sensor