GEAR 2056788 - Caterpillar

System Operation Description:Use this procedure under the following situation:Use this procedure to determine if one of the following switches is preventing normal operation of cruise control, idle set speed, or extended idle:
Cruise control on/off switch
Cruise control set/resume switchThe following switch circuits can also prevent the correct operation of the cruise control, idle set speed, or extended idle:
Service brake pedal position (switch 1)
Service brake pedal position (switch 2)
Clutch pedal position switch
Neutral switch
PTO on/off switch
Cruise control pause switchThe switches are described in the respective circuit tests.All of the following Customer Programmable Parameters can affect cruise control, idle set speed, and extended idle:
"Low Cruise Control Speed Set Limit"
"High Cruise Control Speed Set Limit"
"Idle Vehicle Speed Limit"
"Idle RPM Limit"
"Fast Idle RPM #1"
"Fast Idle RPM #2"
"Cruise/Idle/PTO Switch Configuration"
"Idle/PTO Bump rpm"
"Idle/PTO rpm Ramp Rate"
"PTO Vehicle Speed Limit"The vehicle speed calibration can also affect the cruise control, idle set speed, and extended idle if the vehicle speed calibration is incorrectly programmed. Refer to Troubleshooting, "Customer Specified Parameters".Cruise Control On/Off SwitchThis switch must be ON before cruise control or controlled idle can be activated. This switch is ON when the switch is closed. When the switch is closed the following terminals are connected:
J1/P1:59 (cruise control on/off switch)
J1/P1:5 (AP sensor/switch sensor common)This switch may not be connected to an input on the ECM. The parameter "Cruise Control On/Off Switch" determines the input to the ECM. If the parameter is programmed to "J1/P1:59" a switch must be connected to terminal 59. If the parameter is programmed to one of the J1939 options, the switch position will be transmitted to the ECM over the J1939 data link. If a problem is suspected with the J1939 data link, refer to Troubleshooting, "Powertrain Data Link Circuit - Test".Note: If the vehicle is programmed to use the dedicated PTO, the PTO on/off switch overrides the cruise control on/off switch. The PTO on/off switch overrides the cruise control on/off switch when the vehicle speed is within the range of the "PTO Vehicle Speed Limit" that is programmed.Set/Resume SwitchMomentarily pressing the set switch with the cruise control on/off switch in the ON position and the vehicle speed within the range of the programmed "Low Cruise Control Speed Set Limit" and the "High Cruise Control Speed Set Limit" will activate the cruise or controlled idle, and the ECM will maintain the current speed.[After a speed has been set and the speed is then disengaged with the brake, the clutch, the cruise control pause switch, or the on/off switch, the ECM will seek the previous set speed when the resume switch is toggled. This assumes that the vehicle speed is above the "Low Cruise Control Speed Set Limit" for cruise control or the vehicle speed is below the "Idle/PTO Vehicle Speed Limit" for the idle and the PTO.After a speed has been set, pressing and holding the set/resume switch in position will cause the engine to establish a new set speed. The system's reaction depends on the programming of the "Cruise/Idle/PTO Switch Configuration".When the set/resume switch