2008 Jeep Wrangler Owner's Manual - Page 381

380 MAINTAINING YOUR VEHICLE Loose Fuel Filler Cap Message After fuel is added, the vehicle diagnostic system can determine if the fuel filler cap is possibly loose, improperly installed, or damaged. A "gASCAP" message will be displayed in the odometer. Tighten the gas cap until a clicking sound is heard. This is an indication that the gas cap is properly tightened. Press the odometer reset button to turn the message off. If the problem persists, the message will appear the next time the vehicle is started. This might indicate a damaged cap. If the problem is detected twice in a row, the system will turn on the "Malfunction Indicator Light." Resolving the problem will turn the "Malfunction Indicator Light." off. EMISSIONS INSPECTION AND MAINTENANCE PROGRAMS In some localities, it may be a legal requirement to pass an inspection of your vehicle's emissions control system. Failure to pass could prevent vehicle registration. For states that require an Inspection and Maintenance (I/M), this check verifies the Malfunction Indicator Light (MIL) is functioning and is not on when the engine is running, and that the OBD II system is ready for testing. Normally, the OBD II system will be ready. The OBD II system may not be ready if your vehicle was recently serviced, recently had a dead battery, or a battery replacement. If the OBD II system should be determined not ready for the I/M test, your vehicle may fail the test.