SEAL-O-RING 1171266 - Caterpillar

System Operation Description:Use this procedure under the following situation:The check engine lamp is suspected of operating incorrectly.Note: The check engine lamp is the only standard lamp on these engines. All other lamps are optional.The following background information is related to the following procedure:Check Engine Lamp The check engine lamp is used to provide the following functions:
Indicate the existence of an active diagnostic code.
Indicate driver alert status of the idle shutdown timer.
Display diagnostic flash codes.Power Up Lamp CheckAt powerup, the lamp will turn on for five seconds. The lamp will continue to flash if there is an active diagnostic code.Operation with an Active Diagnostic CodeWhile the engine is operating, the lamp will turn on for a minimum of five seconds when certain fault conditions exist. While these conditions exist, the lamp will operate in the following manner:
The check engine lamp will turn on for five seconds.
The check engine lamp will turn off for a short time.
The check engine lamp will turn on for another five seconds.The check engine lamp will continue to operate in this manner while the fault condition exists.Indication of the Driver Alert Status of the Idle Shutdown TimerDuring the final 30 seconds of the operation of the idle shutdown timer, the check engine lamp will begin to flash. The flashing of the check engine lamp indicates that an engine shutdown is near.Flashing Out Diagnostic Flash Codes The flash codes are two-digit representations of diagnostic codes. The PID-FMI diagnostic code should be used for troubleshooting. The PID is the Parameter Identifier. The FMI is the Failure Mode Identifier. A 110-03 is an example of a PID-FMI diagnostic code. Flash codes provide the operator with a visual warning that the Engine Control Module (ECM) has detected a problem with the engine. Flash codes are not as specific as diagnostic codes. Flash codes only indicate that a problem is occurring. Flash codes do not indicate the specific type of failure. For example, the flash code (27) is used for a 110-03 fault code and a 110-04 fault code. Flash codes should not be used for troubleshooting.Diagnostic flash codes that are active can be viewed at any time. To view a code, turn the cruise control On/Off switch to the OFF position. Hold the set/resume switch in either the SET position or the RESUME position until the lamp begins to flash. Then release the set/resume switch.The flash code is communicated by the blinking of the check engine lamp. The lamp will blink for the first digit of the flash code, and the lamp will pause for five seconds. Then, the lamp will blink for the second digit of the code.Some vehicles are equipped with a diagnostic enable switch. The diagnostic enable switch is used to flash the diagnostic codes by grounding the input of the diagnostic enable switch from P1-46 (Input 7) to P1-5 (sensor common).Electrical Connection of the Check Engine LampOne terminal of the check engine lamp requires a connection to battery voltage. The other terminal is wired to