System Operation Description:
Use this procedure if one of the following switches is suspected of preventing normal operation of cruise control, idle set speed, or PTO operation:
• Cruise Control On/Off Switch
• Cruise Control Set/Resume Switch
• Cruise Control Pause Switch
The following switch circuits can also prevent the correct operation of the cruise control, idle set
speed or PTO operation:
• Service Brake Pedal Position (Switch 1)
• Service Brake Pedal Position (Switch 2)
• Neutral Switch
• PTO On/Off Switch
The switches are described in the respective circuit tests in Troubleshooting.
All of the following customer programmable parameters can affect cruise control, idle set speed, and PTO operation:
• “Adaptive Cruise Control Enable”
• “Low Cruise Control Speed Set Limit”
• “High Cruise Control Speed Set Limit”
• “Idle Vehicle Speed Limit”
• “Cruise/Idle/PTO Switch Configuration”
• “Idle/PTO Bump rpm”
• “Idle/PTO rpm Ramp Rate”
• “PTO Kickout Vehicle Speed Limit”
The vehicle speed calibration can also affect the cruise control, the idle set speed, and the PTO if the vehicle speed calibration is incorrectly programmed. Refer to Troubleshooting, “Customer Specified Parameters”.
Cruise Control On/Off Switch
This 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)
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 will override the cruise control On/Off switch if the vehicle speed is within the programmed range for the “PTO Kickout Vehicle Speed Limit” parameter.
Set/Resume Switch
While the cruise control On/Off Switch is in the ON position and the vehicle speed is within the range of the programmed “Low Cruise Control Speed Set Limit” and the “High Cruise Control Speed Set Limit”, momentarily pressing the set switch will activate the cruise or controlled idle, and the ECM will maintain the current speed.
Pressing the resume switch will cause the vehicle speed to ramp to the last cruise control set speed. 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 is momentarily pressed, the cruise set point will change one mph. The rate of change is dependent on the programmed “Idle/PTO Bump RPM” when an idle speed is set.
Cruise Control Pause Switch
The cruise control pause switch is used to temporarily disable cruise control. The cruise control cannot be set while the cruise control pause switch is in the On position.
Adaptive Cruise Control
The adaptive cruise control is a J1939 based option. A radar is used in order to detect vehicles. When a vehicle is detected the cruise control set speed is reduced in order to maintain a following distance. This option must be enabled with the electronic service tool. Customer passwords are required to enable this option.
If a problem is suspected with the adaptive cruise control, the feature can be disabled. Toggle the cruise control switch to the OFF position and to the ON position twice within 10 seconds.
The following background information is related to this procedure:
The kickout switch refers to the switch that is used to exit the cruise control, the PTO, or the idle set speed.
The operation of the Caterpillar electronic engine cruise control is similar to the operation of the cruise controls that are installed in automobiles. The operation of idle and PTO are similar to the operation of cruise except that the idle and the PTO govern engine rpm instead of vehicle speed.
Note: Idle in this procedure is an engine idle rpm above the programmed low idle rpm. Idle is set with the cruise control On/Off switch and the Set/Resume switch. Refer to Troubleshooting, “PTO Switch Circuit – Test” for additional information regarding the programmable options for the dedicated PTO.
Usage of Transmission Style Switches
The “Transmission Style” parameter determines the switches that will be used. The following switches can be used with being dependent on the parameter setting:
• Clutch Pedal Position
• Neutral
• Service Brake Pedal Position (Switch 1)
• Service Brake Pedal Position (Switch 2)
Refer to Table 3 for additional information.
If the “Transmission Style” parameter is programmed to one of the following options, the input for the clutch pedal position switch is not used:
• Automatic Options 1
• Automatic Option 2
• Automatic Option 3
• Automatic Option 4
A service brake pedal position (Switch 1) is required for all configurations. The service brake pedal position (Switch 1) connects to the ECM through connector P1:45. The service brake pedal position (Switch 2) connects to the ECM through connector P1:64. The clutch pedal position switch connects to the ECM through connector P1:22. The neutral switch connects to the ECM through connector P1:62.
Test Step 1. Check the Status of the Cruise Control On/Off Switch
A. Connect the electronic service tool to the data link connector.
B. Turn the key switch to the ON position.
C. Monitor the status for the “Cruise/Idle On-Off Switch” while the cruise control On/Off switch is cycled.
Expected Result:
The status for the “Cruise/Idle On-Off Switch” is “On” when the cruise control On/Off switch is in the On position. The status for the “Cruise/Idle On-Off Switch” is “Off” when the cruise control On/Off switch is in the Off position.
Results:
• OK – The cruise control On/Off switch is working properly. Proceed to Test Step 2.
• Not OK – The cruise control On/Off switch is not working properly. Proceed to Test Step 3.
Test Step 2. Check the Status of the Set/Resume Switch
A. Put the cruise control On/Off switch in the On position.
B. Monitor the status for the “Cruise Control Set/Resume/Accel/Decel Switch J1/P1:35 & 44” while the Set/Resume switch is cycled.
Expected Result:
The status for the “Cruise Control Set/Resume/Accel/Decel Switch J1/P1:35 & 44” is “Set Switch On” when the Set/Resume switch is in the Set position. The status for the “Cruise Control Set/Resume/Accel/Decel Switch J1/P1:35 & 44” is “Resume Switch On” when the Set/Resume switch is in the Resume position.
Results:
• OK – The cruise control Set/Resume switch is working properly. STOP.
• Not OK – The cruise control Set/Resume switch is not working properly. Proceed to Test Step 3.
Test Step 3. Determine the Configuration of the Cruise Control Switches
A. Determine if the wiring for the cruise control switches is wired directly to the ECM or through the J1939 data link.
B. Verify that the “Cruise Control On/Off Switch” and the “Cruise Control Set/Resume/Accel/Decel Switch” parameters are programmed to reflect the proper wiring.
Expected Result:
The cruise control switches are wired directly to the ECM.
Results:
• OK – The cruise control switches are wired directly to the ECM.
Repair: Verify that the “Cruise Control On/Off Switch” and the “Cruise Control Set/Resume/Accel/Decel Switch” parameters are programmed correctly.
Proceed to Test Step 4.
• Not OK – The cruise control switches are wired through the J1939 data link.
Repair: Verify that the “Cruise Control On/Off Switch” and the “Cruise Control Set/Resume/Accel/Decel Switch” parameters are programmed to “J1939 – Body Controller”, “J1939 – Cab Controller”, or “J1939 – Instrument Cluster”.
Refer to Troubleshooting, “Powertrain Data Link Circuit – Test”.
STOP.
Test Step 4. Inspect Electrical Connectors and Wiring
A. Thoroughly inspect the J1/P1 ECM connector, the firewall bulkhead connector and the terminals for the following switches in the connectors:
• J1/P1:5 (AP Sensor/Switch Sensor Common)
• J1/P1:35 & 44 (Set/Resume Switch)
• J1/P1:59 (Cruise Control On/Off Switch)
Refer to Troubleshooting, “Electrical Connectors – Inspect” for details.
B. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the switches.
Refer to Illustration 74.
C. Check the ECM connector (Allen Head Screw) for the proper torque of 6.0 N·m (55 lb in).
D. Check the harness and wiring for abrasion and pinch points from the sensor to the ECM.
Expected Result:
All connectors, pins and sockets should be completely coupled and/or inserted and the harness and wiring should be free of corrosion, abrasion or pinch points.
Results:
• OK – Proceed to Test Step 5.
• Not OK
Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.
Verify that the repair eliminates the problem.
STOP.
Test Step 5. Check the Switch Circuit at the ECM
A. Turn the key switch to the OFF position.
B. Fabricate a jumper wire 100 mm (4 inch) long.
Crimp a Deutsch pin to both ends of the wires.
C. Disconnect vehicle harness connector P1 from the ECM.
D. Connect a 140-2266 Cable (Seventy-Pin Breakout) between the J1 and P1 ECM connectors.
E. Install the jumper into the suspect switch socket of the breakout T. Connect the other end of the jumper to ECM connector P1:5 (AP Sensor/Switch Sensor Common) of the breakout T.
F. Turn the key switch to the ON position.
G. While the status for the suspect switch is being monitored on the status screen slowly remove the jumper from terminal 5 and slowly insert the jumper from terminal 5 (AP Sensor/Switch Sensor Common) of the breakout T.
Refer to Table 145.
Expected Result:
The switch status changes per the information in Table 145.
Results:
• OK – The ECM is functioning properly.
Repair: Remove the breakout T and reconnect the J1 and P1 ECM connectors.
Proceed to Test Step 6.
• Not OK – The ECM is not functioning properly.
Repair: Perform the following repair:
1. Temporarily connect a test ECM.
2. Remove the breakout T and reconnect the J1 and P1 ECM connectors.
3. If the problem is resolved with the test ECM, reconnect the suspect ECM.
4. If the problem returns with the suspect ECM, replace the ECM.
5. Verify that the repair eliminates the problem.
STOP.
Test Step 6. Insert a Jumper at the Suspect Switch
A. Turn the key switch to the OFF position.
B. Find the suspect switch in the vehicle.
C. Disconnect the wires from the suspect switch terminals.
D. Turn the key switch to the ON position.
E. While the status for the suspect switch is being monitored on the status screen connect the suspect switch wires and disconnect the suspect switch wires.
Refer to Table 146.
Expected Result:
The switch status changes per the information in Table 146.
Results:
• OK
Repair: Perform the following repair:
Replace the faulty switch.
Verify that the repair eliminates the problem.
STOP.
• Not OK – There is a problem in the harness between the switch and the ECM. Proceed to Test Step 7.
Test Step 7. Insert a Jumper at the Bulkhead Connector
A. Turn the key switch to the OFF position.
B. Fabricate a jumper wire 100 mm (4 inch) long.
Crimp a Deutsch pin on both ends of the wires.
C. Find the terminal for the suspect switch and the sensor common on the engine side of the bulkhead connector.
D. Insert the jumper wire between the two terminals in the engine side of the bulkhead connector.
E. Turn the key switch to the ON position.
F. While the status for the suspect switch is being monitored on the status screen remove the jumper wire between the two terminals, and insert the jumper wire between the two terminals.
Refer to Table 147.
Expected Result:
The switch status changes per the information in Table 147.
Results:
• OK – The problem is in the vehicle wiring between the bulkhead connector and the switch.
Repair: Perform the following repair:
Inspect the vehicle wiring and repair the vehicle wiring, as required. If the problem still exists with the wiring, send the vehicle to the OEM dealer.
STOP.
• Not OK – The problem is in the vehicle wiring between the bulkhead connector and the ECM.
Repair: Perform the following repair:
Inspect the vehicle wiring and repair the vehicle wiring, as required. If the problem still exists with the wiring, send the vehicle to the OEM dealer.
STOP.
