Civic L4-1590cc 1.6L SOHC (VTEC) (1992)
(BU) code used when the CHECK ENGINE warning light is on. Jump the service check connector, if no code is displayed (CHECK ENGINE
LIGHT stays on steady), the back-up system is in operation.
Self-diagnosis indicator, (CHECK ENGINE LIGHT) blinks (?), will follow associated systems.
Rough Idle
Check:
1. Electronic Air Control Valve (EACV) (14)
2. Idle Control System
a. Hoses and Connections
b. Electronic Air Control Valve (EACV)
3. Emission Control System
a. Exhaust Gas Recirculation (EGR) Control system (12)
b. Positive Crankcase (PCV) Ventilation System
4. Fuel Supply System
a. Injector Resistor
b. Fuel Injector
c. Contaminated Fuel
5. Manifold Absolute Pressure (MAP) Sensor (3)(5)
6. PGM-FI Control (ECU) Unit (BU)
NOTE:
After each symptom, the system that could be the source of the symptom are listed and should be checked in the order they are listed, beginning
with #1.
(BU) code used when the CHECK ENGINE warning light is on. Jump the service check connector, if no code is displayed (CHECK ENGINE
LIGHT stays on steady), the back-up system is in operation.
Self-diagnosis indicator, (CHECK ENGINE LIGHT) blinks (?), will follow associated systems.