C15 – PTO Switch Circuit – Test

System Operation Description:
Use this procedure under the following situation:

Use this procedure to determine that the vehicle wiring and the ECM are functioning properly for the features of Dedicated PTO.

The following background information is related to this procedure:

INPUT 1

J1/P1:56 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 switch is on, the ECM will be in Dedicated PTO mode.

When the ECM is in the Dedicated PTO mode the PTO Top Engine Limit (TEL) is 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 J1/P1:30 Output 1, the PTO switch on lamp will turn on whenever the PTO on/off circuit is on.

If the problem is with undetermined PTO kick outs, use the following procedure:

Operate the vehicle in PTO mode.

After the kick out, review the status parameter on the electronic service tool. The status parameter indicates the cause of the kick out. This must be performed before the ignition key switch is turned off. It is important to remember that the parameter will only indicate the last kick out since the ECM has been powered by the ignition key switch.

This parameter is blank when the ECM is first powered up. If this parameter is blank “Not Kicked Out” is indicated. This parameter remains blank until the ECM detects the use of the PTO mode. Also, this parameter remains blank until the ECM detects the disengagement of PTO mode. Refer to Table 151 in order to interpret the status parameter.

The following kick out status parameter is available:

• PTO kick out

PTO interlocks may also be connected in series with the PTO on/off switch. The interlocks are intended to prevent the PTO on/off circuit from activating unless certain conditions are met.

INPUT 2

J1/P1:58 Input 2 is used for the PTO set switch when the “PTO Configuration” is programmed to “Remote Switches” or “Remote Throttle”. The PTO set switch can also be used to increase engine rpm.

INPUT 3

J1/P1:60 Input 3 is used for the PTO resume switch when the “PTO Configuration” is programmed to “Remote Switches” or “Remote Throttle”. The PTO resume switch can also be used to decrease engine rpm.

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
• Cruise Control Pause Switch

When the “PTO Configuration” is programmed to “Cab Switches” and the PTO on/off switch is on, the accelerator pedal position sensor that is located in the cab can be limited to one of the following settings by using the “PTO Cab Throttle RPM Limit” parameter:

• Low idle
• PTO Top Engine Limit
• Top engine limit

The “PTO Configuration” Is Programmed 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
• Accelerator pedal position sensor
• Cruise control set/resume switch that is located in the cab

A remote accelerator pedal position sensor is connected to J1/P1:68 Input 8 when the “PTO Configuration” is programmed to “Remote Throttle”.

Note: The wiring for your particular application may be slightly different. The circuits for the sensor common are used interchangeably by the OEM of the vehicle. The following circuits are common within the ECM:

• J1/P1:18 (sensor common 1)
• J1/P1:3 (sensor common 2)
• J1/P1:5 (AP sensor/switch sensor common)

Test Step 1. Use the Electronic Service Tool to Check the Programming of the Parameter “Dedicated PTO Parameters”
A. Connect the electronic service tool to the data link connector.

B. Turn the ignition key switch to the ON position.

C. Access the “Dedicated PTO Parameters” on the electronic service tool. Note the programming of the parameter “PTO Configuration”.

Expected Result:
The “PTO Configuration” is programmed to “Cab Switches”, “Remote Switches”, or “Remote Throttle”.

Results:
• Yes – Proceed to Test Step 2.
• No – The Dedicated PTO features are not programmed for this engine. If PTO operation is desired, the “PTO Configuration” must be programmed to “Cab Switches”, “Remote Switches”, or “Remote Throttle”. STOP.

Test Step 2. Determine the Truck OEM Wiring Installation of the PTO

A. From the programming of the parameter for the “PTO Configuration”, review the truck wiring in order to determine the method of installation of the wiring. Talk to the driver about the use of the PTO.

B. Check the cab glove box for any information regarding the installation of the PTO. It is important to understand the location and the function of the interlock switches for the PTO.

C. Contact the installer of the components that are used for the PTO, if necessary.

D. Determine the schematic that most closely matches the installation. Review the schematics in this procedure for each of the options for the specific “PTO Configuration ”of the truck.

E. Record the “PTO Configuration”.

Expected Result:
The requirements for the installation and the application have been reviewed.

Results:
• OK – Proceed to Test Step 3.

Test Step 3. Inspect Electrical Connectors and Wiring

A. Thoroughly inspect ECM connector J1/P1, 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. The following connections should be tested if the connections are used:

• P1/J1:3
• P1/J1:5
• P1/J1:30
• P1/J1:35
• P1/J1:44
• P1/J1:56
• P1/J1:58
• P1/J1:60
• P1/J1:68

Refer to Illustration 146.

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 4.
• 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 4. Use the Electronic Service Tool to Check the Circuit for the PTO On/Off Switch

A. Turn the ignition key switch to the ON position.

B. For the input 1 (PTO on/off switch), access the electronic service tool status screens that display the following status parameters:
• “PTO Config”
• “PTO On/Off Switch”

C. Verify that each of the interlocks for the PTO are set. Then, while the electronic service tool status screen is being monitored move the PTO on/off switch to the ON position and move the PTO on/off switch to the OFF position.

An example of an interlock for the PTO would be a parking brake that is intended to allow the PTO to control the engine under specific conditions.

Expected Result:

Result 1 The status of the PTO on/off switch on the electronic service tool changes from “OFF” to “ON” when the PTO on/off switch is turned to the OFF position and the ON position, but the set/resume switch is not operating correctly.

Result 2 The status of the PTO on/off switch on the electronic service tool changes from “OFF” to “ON” when the PTO on/off switch is turned to the OFF position and the ON position. However, the remote accelerator is not operating correctly.

Result 3 The status of the PTO on/off switch on the electronic service tool does not change from “OFF” to “ON” when the PTO on/off switch is turned to the OFF position and the ON position.

Results:
• Result 1 – Proceed to Test Step 5.
• Result 2

Repair: Perform the following diagnostic procedure: Troubleshooting, “Remote PTO Accelerator Position Sensor Circuit – Test”

STOP.
• Result 3 – Proceed to Test Step 6.

Test Step 5. Use the electronic service tool to Check the Status of the Set/Resume Input

Note: The set/resume input increases the engine rpm and the set/resume input decreases the engine rpm.

A. Find the PTO set switch. If the “PTO Configuration” is programmed to “Cab Switches”, the cruise control set/resume switch will be used. If the “PTO Configuration” is programmed to “Remote Switches” or “Remote Throttle”, a dedicated PTO set switch will be used.

The “PTO Configuration” is programmed to “Cab Switches”.

Look at the status for the “Cruise Control Set/Resume Switch” parameter on the electronic service tool. The parameter is located on the same status screen as the idle switch.

B. Monitor the status screen of the electronic service tool. Perform the following procedure in order:

• Put the cruise control set/resume switch in the Set position.
• Release the cruise control set/resume switch from the Set position.
• Put the cruise control set/resume switch in the Resume position.
• Release the cruise control set/resume switch from the Resume position.

The “PTO Configuration” is programmed to “Remote Switches” or “Remote Throttle”.

View the status parameter on the electronic service tool for the “Remote PTO Set Switch” and the “Remote PTO Resume Switch”.

C. While the status screen of the electronic service tool for the switch is being monitored, perform the following procedure in order:

• Put the remote PTO set/resume switch in the Set position.
• Release the remote PTO set/resume switch from the Set position.
• Put the remote PTO set/resume switch in the Resume position.
• Release the remote PTO set/resume switch from the Resume position.

Expected Result:
When the “PTO Configuration” is programmed to “Cab Switches”, the status parameter for the cruise control set/resume switch on the electronic service tool behaves in the following manner:

• The status of the cruise control set/resume switch will display “OFF” when the set switch is released.
• The status of the cruise control set/resume switch changes from “OFF” to set switch “ON” when the switch is moved to the SET position.
• The status of the cruise control set/resume switch changes from set switch “ON” to resume switch “ON” when the resume switch is moved to the RESUME position.

When the “PTO Configuration” is programmed to “Remote Switches” or “Remote Throttle”, the status parameter for the remote PTO set switch behaves in the following manner:

• The status screen for the remote PTO set switch displays “OFF” when the remote PTO set switch is released.
• The status of the remote PTO resume switch displays “OFF” when the remote PTO resume switch is released.
• The status of the remote PTO set switch changes from “OFF” to set switch “ON” when the remote PTO set switch is moved to the SET position.
• The status of the remote PTO resume switch changes from “OFF” to resume switch “ON” when the remote PTO resume switch is moved to the RESUME position.

Results:
• Yes – The set circuit and the resume circuit are functioning correctly. The inputs for the PTO are functioning properly. Continue troubleshooting if the original condition is not resolved. STOP.

• No (programmed to “Cab Switches”) – The “PTO Configuration” is programmed to “Cab Switches”. Proceed to Test Step 7.

• No (programmed to “Remote Switches” or “Remote Throttle”) – The “PTO Configuration” is programmed to “Remote Switches” or “Remote Throttle”. Proceed to Test Step 8.

Test Step 6. Use the Electronic Service Tool to Check the Status of the PTO On/Off Switch

A. Turn the ignition 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. Disconnect vehicle harness connector P1 from the ECM.

D. Connect a breakout T to ECM connector J1 and connect P1 to the breakout T.

E. Connect the electronic service tool to the data link connector.

F. Turn the ignition key switch to the ON position.

G. Access the “PTO On/Off Switch” status on Cat ET.

H. While the switch status is being observed on the electronic service tool, install the jumper into the breakout T between J1/P1:56 (input 1) and J1/P1:3 (input sensor common 2).

The input 1 is the PTO on/off switch.
Refer to Illustration 147.

Expected Result:
The switch status of the “PTO On/Off Switch” on the electronic service tool behaves in the following manner:

• The switch status changes from “OFF” to “ON” when the jumper is in place.
• The switch status is “OFF” when the jumper is removed.

Results:
• Yes – The input 1 (PTO on/off switch) of the ECM is functioning correctly. The problem is in the switches of the vehicle or the problem is in the wiring of the vehicle.

Repair: Inspect the wiring. Select one of the
following options:
• Repair the wiring or replace the wiring.
• Send the vehicle to the OEM dealer for repair.

Verify that the repair eliminates the problem.
STOP.

• No – 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 all jumpers and replace all connectors.
4. Recheck the system for active diagnostic codes.
5. Repeat the test step.
6. If the problem is resolved with the test ECM, reconnect the suspect ECM.
7. If the problem returns with the suspect ECM, replace the ECM.
8. Verify that the repair eliminates the problem.

STOP.

Test Step 7. Use the Electronic Service Tool to Check the Status of the Cruise Control Set/Resume Switch

A. Turn the ignition 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. Disconnect vehicle harness connector P1 from the ECM.

D. Connect a breakout T to ECM connector J1 and connect P1 to the breakout T.

E. Connect the electronic service tool to the data link connector.

F. Turn the ignition key switch to the ON position, while the engine is off.

G. Access the status of the cruise control set/resume switch on the electronic service tool.

H. While the switch status is being observed on the electronic service tool, install the jumper into the breakout T in order to connect P1/J1:35 (Set) to P1/J1:5 (AP sensor/switch sensor common). Also, while the switch status is being observed on the electronic service tool remove the jumper from the breakout T in order to disconnect P1/J1:35 (Set) fromP1/J1:5 (AP sensor/switch sensor common).

I. While the switch status is being observed on the electronic service tool, install the jumper into the breakout T. This connects P1/J1:44 (resume) to P1/J1:5 (AP sensor/switch sensor common). Also, while the switch status is being observed on the electronic service tool, remove the jumper from the breakout T. This will disconnect P1/J1:44 (resume) from P1/1:5 (AP sensor/switch sensor common).

Refer to Illustration 148.

Expected Result:
The switch status of the cruise control set/resume
switch on the electronic service tool behaves in the
following manner:

• The switch status of the cruise control set/resume switch changes from “OFF” to set switch “ON” when the jumper is connected from P1/J1:35 (Set) to P1/J1:5 (AP sensor/switch sensor common).
• The switch status of the cruise control set/resume switch is “OFF” when the jumper is removed.
• The switch status of the cruise control set/resume switch changes from “OFF” to resume switch
“ON” when the jumper is connected from P1/J1:44 (switch resume terminal) to J1/P1:5 (AP sensor/switch sensor common).

Results:
• Yes – The input for the set switch and the input for the resume switch of the ECM are functioning correctly. The problem is in the switches of the vehicle or the problem is in the wiring of the vehicle.

Repair: Inspect the wiring. Select one of the following options:
• Repair the wiring or replace the wiring.
• Send the vehicle to the OEM dealer for repair.

Verify that the repair eliminates the problem.

STOP.

• No – 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 all jumpers and replace all connectors.
4. Recheck the system for active diagnostic codes.
5. Repeat the test step.
6. If the problem is resolved with the test ECM, reconnect the suspect ECM.
7. If the problem returns with the suspect ECM, replace the ECM.
8. Verify that the repair eliminates the problem.

STOP.

Test Step 8. Use the Electronic Service Tool to Check the Status of the Remote PTO Set Switch and the Remote PTO Resume Switch

A. Turn the ignition 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. Disconnect vehicle harness connector P1 from the ECM.

D. Connect a breakout T to ECM connector J1 and connect P1 to the breakout T.

E. Connect the electronic service tool to the data link connector.

F. Turn the ignition key switch to the ON position.

G. Access the “Remote PTO Set Switch” and “Remote PTO Resume Switch” status on the electronic service tool.

H. While the status of the “Remote PTO Set Switch” is being observed on the electronic service tool, install the jumper into the breakout T in order to connect J1/P1:58 (Input 2) to J1/P1:3 (Input sensor common 2). Also, while the switch status is being observed on the electronic service tool remove the jumper from the breakout T in order to disconnect J1/P1:58 (Input 2) from J1/P1:3 (Input sensor common 2).

I. While the status of the “Remote PTO Resume Switch” is being observed on the electronic service tool, install the jumper into the breakout T in order to connect J1/P1:60 (Input 3) to J1/P1:3 (Input sensor common 2). Also, while the switch status is being observed on the electronic service tool remove the jumper from the breakout T in order to disconnect J1/P1:60 (Input 3) from J1/P1:3 (Input sensor common 2). The J1/1:58 Input 2 is the set switch for the PTO and the J1/P1:60 Input 3 is the resume switch for the PTO.

Refer to Illustration 149.

Expected Result:
The switch status of the “Remote PTO Set Switch” on the electronic service tool behaves in the following manner:

• The switch status of the “Remote PTO Set Switch” is “OFF” when the jumper is removed.
• The switch status of the “Remote PTO Set Switch” changes from “OFF” to set switch “ON” when the jumper is connected from J1/P1:58 (Input 2) to J1/P1:3 (Input Sensor Common 2).
The switch status of the “Remote PTO Resume Switch” on the electronic service tool behaves in the following manner:

• The switch status of the “Remote PTO Resume Switch” is “OFF” when the jumper is removed.
• The switch status of the “Remote PTO Resume Switch” changes from “OFF” to resume switch “ON” when the jumper is connected from J1/P1:60 (Input 3) to J1/P1:3 (Input sensor common 2).

Results:
• Yes – Input 2 (“Remote PTO Set Switch”) and input 3 (“Remote PTO Resume Switch”) of the ECM are functioning correctly. The problem is in the switches of the vehicle or the problem is in the wiring of the vehicle.

Repair: Inspect the wiring. Select one of the following options:
• Repair the wiring or replace the wiring.
• Send the vehicle to the OEM dealer for repair.

Verify that the repair eliminates the problem.

STOP.

• No – 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 all jumpers and replace all connectors.
4. Recheck the system for Active diagnostic codes.
5. Repeat the test step.
6. If the problem is resolved with the test ECM, reconnect the suspect ECM.
7. If the problem returns with the suspect ECM, replace the ECM.
8. Verify that the repair eliminates the problem.

STOP.

 

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