Sorry bro, your wrong...There is such a thing as an ECU trouble code...Here are all of the ECU codes for 4G ludes:

TROUBLE CODES

0 - ECU
1 - o2 Sensor
3 - MAP Sensor
5 - MAP Sensor
4 - Crankshaft Position Sensor
6 - Engine Coolant Temp Sensor
7 - Throttle Position Sensor
8 - TDC Position Sensor
9 - #1 Cylinder Sensor
10 - Idle Air Temp Sensor
12 - EGR Valve Lift Sensor
13 - Barometric Pressure Sensor
14 - Idle Air Control Sensor
15 - Ignition Output Sensor
16 - Fuel Injector
17 - Vehicle Speed Sensor
20 - Electrical Load Detector
21 - VTEC Solenoid Switch
22 - VTEC Pressure Switch
23 - Knock Sensor
30 - A/T Sig A
31 - A/T Sig B
41 - o2 sensor heater
43 - Fuel Supply System

you want me to list gear ratio compressions for 4g's too???:naughty:

Hope these help bro
Rezza