2005 Honda Civic Owner's Manual - Page 199

Malfunction Indicator Lamp If the indicator comes on while driving, it means one of the engine's emissions control systems may have a problem. Even though you may feel no difference in your vehicle's performance, it can reduce your fuel economy and cause increased emissions. Continued operation may cause serious damage. If you have recently refueled your vehicle, the indicator coming on could be due to a loose or missing fuel fill cap. Tighten the cap until it clicks at least three times. Tightening the cap will not turn the indicator off immediately; it takes at least three days of normal driving. If the indicator comes on repeatedly, even though it may turn off as you continue driving, have the vehicle checked by your dealer as soon as possible. If your vehicle battery has been disconnected or gone dead, these codes are erased. It takes at least three days of driving under various conditions to set the codes again. To check if they are set, turn the ignition switch to ON (II), without starting the engine. The Malfunction Indicator Lamp will come on for 20 seconds. If it then goes off, the readiness codes are set. If it blinks 5 times, the readiness codes are not set. If possible, do not take your vehicle for a state emissions test until the readiness codes are set. Refer to State Emissions Testing for more information (see page 222 ). If you keep driving with the Malf unction Indicator Lamp on, you can damage your vehicle's emissions controls and the engine. Those repairs may not be covered by your vehicle's warranties. Readiness Codes Your vehicle has certain ''readiness codes'' that are part of the on-board diagnostics for the emissions systems. In some states, part of the emissions testing is to make sure these codes are set. If they are not set, the test cannot be completed. Taking Care of the Unexpected 201