Probable Causes
The probable root causes are listed below:
• A clutch pedal position switch that is incorrectly adjusted
• Malfunctioning On/Off switch for cruise control and idle control
• Malfunctioning switch for Service Brake Pedal Position
• Malfunctioning Transmission Neutral Switch
• Vehicle Speed circuit problem
• Battery power or ground to the ECM
• Adaptive cruise control
Recommended Actions
Perform the following diagnostic procedures in order:
1. Connect Cat ET to the data link connector.
Check the Status Screen for the last item that caused the Kickout for the Cruise Control, the Idle Control or the PTO Control.
Note: Cat ET will only provide access to the last cause of the Kickout. If the ECM is powered down
and the ECM is powered up, the display on Cat ET will be blank. The ECM is powered down when the
ignition key switch is turned to the OFF position.
It may be necessary to take the vehicle for a test drive in order to repeat the problem. Check Cat ET before the ECM is turned off by the keyswitch.
If Cat ET indicates “Switch Turned Off”, go to Step 2.
If Cat ET indicates “Brake”, “Clutch” or “Neutral” go to Step 3.
If the Cat ET indicates “Bad Vehicle Speed”, “Vehicle Speed < Limit” or “Vehicle Speed >=
Limit” go to Step 4.
2. If Cat ET indicates “Switch Turned Off”, the ECM has detected an open circuit in the On/Off switch
circuit. This pertains to the cruise control, the idle control or the PTO. Perform the following tests in order:
a. Ensure that the operator has not actually turned off the Cruise Control On/Off Switch or
the PTO On/Off Switch.
b. Check the Status Screen on Cat ET while the switch is being used. If the problem is not
apparent check the switch and the wiring.
c. If the problem is related to the Cruise Control or Idle Control refer to Troubleshooting, “Cruise Control Circuit, Service Brake Pedal Position (Switch 1) Circuit, and Clutch Pedal Position Switch Circuit – Test”.
d. If the problem is related to the PTO refer to Troubleshooting, “PTO Switch Circuit – Test”.
3. If Cat ET indicates “Brake”, “Clutch” or “Neutral”, the ECM has detected an open circuit in the
switch circuit for the Service Brake, the switch circuit for the Clutch or the Transmission Neutral
switch circuit. Perform the following tests in order:
a. Ensure that the operator has not actually depressed the service brake pedal or the clutch pedal. Also ensure that the operator has not actually shifted the transmission to neutral.
b. Check the status screen on Cat ET while the service brake or the clutch is being used.
If the problem is not apparent check the switches. Check the service brake switch for
the air system. Ensure that the treadle valve is operating freely. A treadle valve that is not operating freely can cause pressure spikes.
Check the clutch switch adjustment and the return spring.
c. If the problem is related to the Cruise Control or Idle Control refer to Troubleshooting, “Cruise Control Circuit, Service Brake Pedal Position (Switch 1) Circuit, and Clutch Pedal Position Switch Circuit – Test”.
d. If the problem is related to the PTO refer to Troubleshooting, “PTO Switch Circuit – Test”.
4. If Cat ET indicates “Bad Vehicle Speed”, the vehicle speed signal is erratic or intermittent.
This relates to Cruise Control only.
If Cat ET indicates “Vehicle Speed < Limit”, the vehicle speed signal was lost at least briefly. This
pertains to Cruise Control only.
If Cat ET indicates “Vehicle Speed >= Limit”, the vehicle speed signal exceeded the programmed Idle/PTO Vehicle Speed Limit or the vehicle speed limit is erratic or intermittent. This pertains to Idle Control and PTO Control only.
Perform the following diagnostic procedure in order:
a. Inspect the Vehicle speed sensor for debris on the sensor. Inspect the vehicle speed circuit.
b. Check the vehicle speed that is displayed on the status screen on Cat ET while the vehicle is parked. Adjust the engine rpm up and down. Also check the vehicle speed while the vehicle is being driven in order to determine that the vehicle speed that is indicated by Cat ET does not vary significantly from
the vehicle speed that is indicated by the speedometer. If the problem is not apparent, refer to Troubleshooting, “Vehicle Speed Circuit – Test”.
c. Inspect both ECM connectors for moisture.
Refer to Troubleshooting, “Inspecting Electrical Connectors”.
5. A problem with the battery power, the ground to the ECM or the vehicle wiring can cause erratic engine rpm or other more severe problems. If this is a suspected cause, refer to Troubleshooting, “Ignition Key Switch Circuit and Battery Supply Circuit Test”.
6. Check for proper operation of the Adaptive Cruise Control.
a. Toggle the cruise control switch to the OFF position and to the ON position twice within
10 seconds. This will disable the Adaptive Cruise Control.
b. Attempt to set the cruise control. Operate the vehicle under the same conditions that caused the problem.
c. If the problem still exists, then the problem is not the Adaptive Cruise Control.
d. If the problem is fixed, refer to Eaton for the proper troubleshooting procedure.
