Way to check codes on your civic (EF, EG, EK, Gen-1 CRV).
If you go to passenger side kick panel and raise up the carpet u sould see your ecu. and above your ECU there will be a plug. It has 2 wires coming out of it. I take a spare piece of thin speaker wire and cut off both ends so that the actual copper of the wire is showion on both ends. i twist up both ends so that they are in a nice point. stick one end of the wire into the first socket on the plug. The other end of the wire into the other socket.

from hondaclub.com.ph

Turn your key to the ON position.. dont start your car. just to the ON position. Watch your check engine light on your cluster. it will flash.. 1 long flash is 10. the quick flashes are one. so if ur CEL goes !.....!!! that is a code 13. !....!....!!!!! code 25. then take the code #'s and hop on this thread and see what it is.

1 O2A - Oxygen sensor #1
2 O2B - Oxygen sensor #2
3 MAP - manifold absolute pressure sensor
4 CKP - crank position sensor
5 MAP - manifold absolute pressure sensor
6 ECT - water temperature sensor
7 TPS - throttle position sensor
8 TDC - top dead centre sensor
9 CYP - cylinder sensor
10 IAT - intake air temperature sensor
12 EGR - exhaust gas recirculation lift valve
13 BARO - atmospheric pressure sensor
14 IAC (EACV) - idle air control valve
15 Ignition output signal
16 Fuel injectors
17 VSS - speed sensor
19 Automatic transmission lockup control valve
20 Electrical load detector
21 VTEC spool solenoid valve
22 VTEC pressure valve
23 Knock sensor
30 Automatic transmission A signal
31 Automatic transmission B signal
36 traction control found on JDM ecu's
41 Primary oxygen sensor heater
43 Fuel supply system
45 Fuel system too rich or lean
48 LAF - lean air fuel sensor
54 CKF - crank fluctuation sensor
58 TDC sensor #2
61 Primary oxygen sensor
63 Secondary oxygen sensor
65 Secondary oxygen sensor heater
71 random misfire cylinder 1
72 random misfire cylinder 2
73 random misfire cylinder 3
74 random misfire cylinder 4
80 Exhaust Gas Recirculation insufficient flow detected
86 ECT Sensor (Engine Coolant Temperature) circuit range / performance problem
90 Evaporative Emission Control System leak detected in the fuel tank area
91 Fuel Tank Pressure Sensor low input
92 Evaporative Emission Control System insufficient purge flow