System Operation Description:
Use this procedure under the following situation:
The vehicle wiring and the ECM are suspected of not functioning properly for the features of dedicated PTO.
The following background information is related to this procedure:
INPUT 1
INPUT 1 is used for the circuit for the PTO On/Off Switch when the PTO configuration is programmed to Cab Switches, Remote Switches or Remote Throttle.
When the PTO On/Off circuit is on, the ECM will be in dedicated PTO mode.
When the ECM is in the dedicated PTO mode the engine retarder is disabled and the PTO Top Engine Limit (TEL) and the torque limit are activated. The engine may proceed directly to the PTO Engine rpm Set Speed if the parameter is programmed. If a PTO Switch ON Lamp is connected to the OUTPUT 1, the PTO Switch ON Lamp will turn on whenever the PTO On/Off circuit is on.
INPUT 2
The INPUT 2 is used for the PTO Set/Accel Switch when the PTO configuration is programmed to Remote Switches or Remote Throttle.
INPUT 3
The INPUT 3 is used for the PTO Resume/Decel Switch when the PTO configuration is programmed to Remote Switches or Remote Throttle.
The PTO Configuration Is Set To Cab Switches. When the PTO configuration is programmed to Cab Switches and the PTO On/Off switch is on, the following circuits can be used to interrupt a set rpm:
• Cruise Control Set/Resume Switch
• Service Brake Pedal Position Switch 1
• Service Brake Pedal Position Switch 2
• Clutch Pedal Position Switch
• Neutral Switch
The engine speed can be limited if the “PTO Configuration” is programmed to “Cab Switches” and the PTO On/Off switch is in the On position. The engine speed can be limited by setting the “PTO Cab Throttle RPM Limit” parameter:
• Low Idle
• PTO Top Engine Limit
• Top Engine Limit
The “PTO Configuration” is set to Remote Switches or Remote Throttle.
When the “PTO Configuration” is programmed to Remote Switches or Remote Throttle and the PTO On/Off switch is on, the following circuits are ignored:
• Service Brake Pedal Position Switch 1
• Service Brake Pedal Position Switch 2
• Clutch Pedal Position Switch
• Neutral Switch
• Cab Accelerator Pedal Position Sensor
• Cab Cruise Control Set/Resume Switch
A remote accelerator position sensor is connected to the INPUT 8 when the PTO configuration is programmed to Remote Throttle.
Test Step 1. Check the Status of the “PTO 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 of the “PTO On/Off Switch” while the PTO On/Off switch is moved to the On position and the Off position.
Expected Result:
The status of the “PTO On/Off Switch” is “On” when the PTO On/Off switch is in the On position. The status of the “PTO On/Off Switch” is “Off” when the PTO On/Off switch is in the Off position.
Results:
• OK – The PTO On/Off switch is working correctly.
Proceed to Test Step 2.
• Not OK – The PTO On/Off switch is not working correctly. Proceed to Test Step 3.
Test Step 2. Check Status of the Set/Resume Input
A. Turn the key switch to the ON position.
B. Check the “PTO Configuration” on the “Configuration” screen on the electronic service tool.
C. The “PTO Configuration” is programmed to “Cab Switches”.
Monitor the status of the “Cruise Control
Set/Resume/Accel/Decel Switch” while the cruise control Set/Resume switch is moved to the Set position and the Resume position.
D. The “PTO Configuration” is programmed to “Remote Switches” or “Remote Throttle”. Monitor the status of the “Remote PTO Set Switch” while the PTO Set switch is moved to the Set position and the Off position.
Monitor the status of the “Remote PTO Resume Switch” while the PTO Resume switch is moved to the Resume position and the Off position.
Expected Result:
The switch status is “Off” when the switch is in the Off position. The switch status is “Set Switch On” when the switch is in the Set position. The switch status is “Resume Switch On” when the switch is in the Resume position.
Results:
• OK – The Set/Resume switch is working correctly.
Repair: If the problem only occurs under certain conditions, check the programmable parameters.
Refer to Troubleshooting, “Dedicated PTO Parameters” for more information on parameters that could cause the PTO not to work.
STOP.
• Not OK – The Set/Resume switch is not working correctly. Proceed to Test Step 3.
Test Step 3. Determine the Configuration of the PTO Switches
A. Determine if the wiring for the PTO switches is wired directly to the ECM or through the J1939 data link.
B. Verify that the “PTO Configuration”, “PTO On/Off Switch”, “Remote PTO Set Switch”, and “Remote PTO Resume Switch” parameters are programmed to reflect the proper wiring.
Expected Result:
The PTO switches are wired directly to the ECM.
Results:
• OK – The PTO switches are wired directly to the ECM.
Repair: Verify that the “PTO Configuration”, “PTO On/Off Switch”, “Remote PTO Set Switch”, and
“Remote PTO Resume Switch” parameters are programmed to reflect the proper wiring.
Proceed to Test Step 4.
• Not OK – The PTO switches are wired through the J1939 data link.
Repair: Verify that the “PTO On/Off Switch”, “Remote PTO Set Switch”, and “Remote PTO Resume 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 connectors, and any connectors that are used by the PTO.
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 connections for the PTO.
Refer to Illustration 139.
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 1.
• Not OK
Repair: Perform the following diagnostic
procedure:
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 Inputs for the PTO On/Off Switch
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 wire.
C. Connect a 140-2266 Cable (Seventy-Pin Breakout) between the J1 and P1 ECM connectors.
D. Turn the key switch to the ON position.
E. Access the “PTO On/Off Switch” status on the electronic service tool.
F. While the status of the “PTO On/Off Switch” is being observed on the electronic service tool, install the jumper into terminal 56 (Input 1) and terminal 3 (Input Sensor Common #2) of the breakout T.
Refer to Illustration 140.
Expected Result:
The status of the “PTO On/Off Switch” is “Off” when the jumper wire is removed. The status of the “PTO On/Off Switch” is “On” when the jumper wire is installed.
Results:
• OK – The ECM is reading the proper state of the PTO On/Off switch. Proceed to Test Step 6.
• Not OK – The ECM is not reading the switch status change.
Repair: Perform the following diagnostic
procedure:
1. Temporarily connect a test ECM.
2. Ensure that the “PTO Configuration” of the test ECM matches the “PTO Configuration” of the suspect ECM.
3. Remove the breakout T and reconnect the J1 and P1 ECM connector.
4. If the problem is resolved with the test ECM, reconnect the suspect ECM.
5. If the problem returns with the suspect ECM, replace the ECM.
6. Verify that the repair eliminates the problem.
STOP.
Test Step 6. Check the Inputs for the Set/Resume Switch
A. Fabricate a jumper wire 100 mm (4 inch) long.
Crimp a Deutsch pin to each end of the wire.
B. Turn the key switch to the ON position.
C. The “PTO Configuration” is programmed to “Cab Switches”.
Access the status for the “Cruise Control Set/Resume/Accel/Decel Switch” on the electronic service tool.
Insert the jumper wire into terminal 5 and terminal 35 (Set Switch).
While the status for the “Cruise Control Set/Resume/Accel/Decel Switch” is monitored remove the jumper wire from terminal 35 (Set Switch) and insert the jumper wire into terminal 44 (Resume Switch).
Refer to Illustration 141.
D. The “PTO Configuration” is programmed to “Remote Switches” or “Remote Throttle”.
Access the status for the “Remote PTO Set Switch” and “Remote PTO Resume Switch” on the electronic service tool.
Insert the jumper wire into terminal 3 and terminal 58 (Set Switch).
While the status for the “Remote PTO Set Switch” and “Remote PTO Resume Switch” is monitored remove the jumper wire from terminal 58 (Set Switch) and insert the jumper wire into terminal 60 (Resume Switch).
Refer to Illustration 142.
Expected Result:
The switch status is “Off” when the jumper wire is not installed. The switch status is “Set Switch On” when the jumper wire is installed between the inputs for the set switch. The switch status is “Resume Switch On” when the jumper wire is installed between the inputs for the resume switch.
Results:
• OK – The input for the set switch and the resume
switch are functioning correctly.
Repair: Remove the breakout T and reconnect the J1 and P1 ECM connector.
Proceed to Test Step 7.
• Not OK – The ECM is not reading the switch status change.
Repair: Perform the following diagnostic
procedure:
1. Temporarily connect a test ECM.
2. Ensure that the “PTO Configuration” of the test ECM matches the “PTO Configuration” of the suspect ECM.
3. Remove the breakout T and reconnect the J1 and P1 ECM connector.
4. If the problem is resolved with the test ECM, reconnect the suspect ECM.
5. If the problem returns with the suspect ECM, replace the ECM.
6. Verify that the repair eliminates the problem.
STOP.
Test Step 7. Check the Switch for Proper Operation
A. Fabricate a jumper wire 100 mm (4 inch) long.
B. Turn the key switch to the ON position.
C. The “PTO Configuration” is programmed to “Cab Switches”.
Access the status for the “Cruise Control Set/Resume/Accel/Decel Switch” on the electronic service tool.
While the status for the “Cruise Control Set/Resume/Accel/Decel Switch” is monitored, insert the jumper wire across the terminals of the set switch. Remove the jumper wire from the set switch and insert the jumper wire across the terminals of the resume switch.
D. The “PTO Configuration” is programmed to “Remote Switches” or “Remote Throttle”.
Access the status for the “Remote PTO Set Switch” and “Remote PTO Resume Switch” on the electronic service tool.
While the status for the “Remote PTO Set Switch”
and “Remote PTO Resume Switch” is monitored,
insert the jumper wire across the terminals of the
set switch. Remove the jumper wire from the
set switch and insert the jumper wire across the
terminals of the resume switch.
Expected Result:
The switch status is “Off” when the jumper wire is not installed. The switch status is “Set Switch On” when the jumper wire is installed between the terminals for the set switch. The switch status is “Resume Switch On” when the jumper wire is installed between the terminals for the resume switch.
Results:
• OK – The switch is not operating correctly.
Repair: Replace the suspect switch.
Verify that the repair eliminates the problem.
STOP.
• Not OK – There is a problem in the wiring between the switch and the ECM.
Repair: Inspect the wiring between the switch and the ECM. Repair the wiring or replace the wiring.
Verify that the repair eliminates the problem.
STOP.
