SWITCH AS-PRESSURE 3E7688 - Caterpillar

System Operation Description:Use this procedure under the following situation:Use the following information in order to determine if the check engine lamp is operating incorrectly:The check engine lamp is the only standard lamp that is used.The following background information is related to the following procedure:Check Engine LampThe 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.
Read 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. If certain fault 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 90 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 an indication of a failure. Flash codes are not as specific as diagnostic codes. Flash codes only indicate that a failure has occurred. 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. 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 determined 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.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 terminal 46 to terminal 5 (sensor common). The customer parameter "Diagnostic Enable" must be programmed to "J1/P1:46" to use terminal 46 as an input for a diagnostic enable switch. A switch does not need to be connected to an ECM input in order to be used as a diagnostic enable switch.