C-10, C-12, 3406E, C-15, C-16 and C-18 Engines - Electronic PTO Installation and Application Caterpillar

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.

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

Operate the vehicle in PTO mode.

After the kickout, review the status on the Caterpillar Electronic Technician (Cat ET). The status on Cat ET indicates the cause. This must be performed before the ignition key switch is turned off. It is important to remember that the status will only indicate the last kickout since the ECM has been powered by the ignition key switch.

This status is blank when the ECM is first powered up. If this status is blank, "No Occurrence" is indicated. This status remains blank until the ECM detects the use of the PTO mode. Also, this status remains blank until the ECM detects the disengagement of PTO mode. Refer to table 1 in order to interpret the status screen.

The status is available for the following kickouts:

• PTO Kickout

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

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.

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:

• The "Input Sensor Common 1" is terminal 18.

• The "Input Sensor Common 2" is terminal 3.

• The "AP Sensor/Switch Sensor Common" is terminal 5.

Illustration 1	g00644420
This illustration is for the schematic for "cab switches" for "PTO configuration".

Illustration 2	g00644427
This illustration is for the schematic for "remote switches" for "PTO configuration".

Illustration 3	g00644448
This illustration is for the schematic for "remote throttle" for "PTO configuration".

Test Step 1. Check the Programming of the Dedicated PTO Customer Parameter

1. Connect Cat ET to the data link connector.

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

3. Access the "Dedicated PTO Parameters" on Cat ET. Note the programming of the "PTO Configuration" parameter.

Expected Result:

The PTO configuration is programmed to either Cab Switches, Remote Switches, or Remote Throttle.

Results:

• OK - Proceed to Test Step 2.

• Not OK - The dedicated PTO features are not programmed for this engine. If PTO operation is desired, the PTO configuration must be programmed to either Cab Switches, Remote Switches, or Remote Throttle. Stop.

Test Step 2. Determine the Setup for the PTO

1. From the programming of the "PTO Configuration" parameter, 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.

2. 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 PTO Interlocks that are used in the installation.

3. Contact the installer of the PTO component, if necessary.

4. 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.

5. 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

Illustration 4	g00713728
Terminal locations for ECM

1. 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.

2. 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:
   • Terminal 3

   • Terminal 5

   • Terminal 30

   • Terminal 35

   • Terminal 44

   • Terminal 56

   • Terminal 58

   • Terminal 60

   • Terminal 68

   Refer to Illustration 4.

3. Check the ECM Connector (Allen Head Screw) for the proper torque of 6.0 N·m (55 lb in).

4. 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. Check the Circuit for the PTO On/Off Switch

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

2. For the INPUT 1 (PTO On/Off Switch), access the status screens on Cat ET that display the following status parameters:
   • PTO Configuration

   • PTO ON/OFF Switch

3. Verify that each of the PTO Interlocks are set. Then, while the status screen is being monitored turn on the PTO On/Off switch and turn off the PTO On/Off switch.

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

Expected Result:

Result 1 When the PTO On/Off switch is turned on, the status of the PTO On/Off switch changes from "OFF" to "ON", but the Set/Resume switch is not operating correctly.

Result 2 When the PTO On/Off switch is turned on, the status of the PTO On/Off switch changes from "OFF" to "ON". However, the remote accelerator is not operating correctly.

Result 3 When the PTO On/Off switch is turned on, the status of the PTO On/Off switch does not change from "OFF" to "ON".

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. Check Status of the Set/Resume Input

Note: The Set/Resume input increases the engine rpm and the Set/Resume input decreases the engine rpm.

1. Find the PTO Set/Resume 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/Resume switch will be used.

   The "PTO Configuration" is programmed to Cab Switches.

   Look at the status of the "Cruise Control Set/Resume Switch" parameter on Cat ET. The parameter is located on the same status screen as the Cruise/Idle switch.

2. While the status screen for the switch is being monitored, 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 Cat ET for the "Remote PTO Set Switch" and the "Remote PTO Resume Switch".

3. While the status screen 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 Cat ET 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 of the "Remote PTO Set Switch" displays "OFF" when the set switch is released.

• The status of the "Remote PTO Resume Switch" displays "OFF" when the resume switch is released.

• The status of the "Remote PTO Set Switch" changes from "OFF" to "Set Switch ON" when the 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 resume switch is moved to the RESUME position.

Results:

• OK - The set circuit and the resume circuit are functioning correctly. The PTO Inputs are functioning properly. Continue troubleshooting if the original condition is not resolved. Stop.

• Not OK (Programmed to Cab Switches) - The PTO Configuration is programmed to Cab Switches. Proceed to Test Step 7.

• Not OK (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. Check the Status of the PTO On/Off Switch

Illustration 5	g00644480
ECM Breakout T-connector

1. Turn the ignition key switch to the OFF position.

2. Fabricate a jumper wire 100 mm (4 inch) long. Crimp a Deutsch pin to both ends of the wire.

3. Disconnect vehicle harness connector P1 from the ECM.

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

5. Connect Cat ET to the data link connector.

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

7. Access the "PTO On/Off Switch" status on Cat ET.

8. While the switch status is being observed on Cat ET install the jumper into the breakout T in order to connect terminal 56 (Input 1) to terminal 3 (Input Sensor Common #2).

   The Input 1 is the PTO On/Off Switch.

   Refer to Illustration 5.

Expected Result:

The switch status of the "PTO On/Off Switch" on Cat ET behaves in the following manner:

• The switch status is "OFF" when the jumper is removed.

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

Results:

• OK - 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.

• 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 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. Check the Status of the Cruise Control Set/Resume Switch

Illustration 6	g00713811
ECM Breakout T-connector

1. Turn the ignition key switch to the OFF position.

2. Fabricate a jumper wire 100 mm (4 inch) long. Crimp a Deutsch pin to each end of the wire.

3. Disconnect the P1 ECM connector from the ECM.

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

5. Connect Cat ET to the data link connector.

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

7. Access the status for the cruise control Set/Resume switch on Cat ET.

8. While the switch status is being observed on Cat ET install the jumper into the breakout T in order to connect terminal 35 (SET) to terminal 5 (AP Sensor/Switch Sensor Common). Also, while the switch status is being observed on Cat ET remove the jumper from the breakout T in order to disconnect terminal 35 (SET) from terminal 5 (AP Sensor/Switch Sensor Common).

9. While the switch status is being observed on Cat ET, install the jumper into the breakout T. This connects terminal 44 (Resume) to terminal 5 (AP Sensor/Switch Sensor Common). Also, while the switch status is being observed on Cat ET, remove the jumper from the breakout T. This will disconnect terminal 44 (Resume) from terminal 5 (AP Sensor/Switch Sensor Common).

   Refer to Illustration 6.

Expected Result:

The switch status of the cruise control Set/Resume switch on Cat ET behaves in the following manner:

• 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 "Set Switch ON" when the jumper is connected from terminal 35 (SET) to terminal 5 (AP Sensor/Switch Sensor Common).

• The switch status of the cruise control Set/Resume switch changes from "OFF" to "Resume Switch ON" when the jumper is connected from terminal 44 (Switch Resume Terminal) to terminal 5 (AP Sensor/Switch Sensor Common).

Results:

• OK - The set input and the resume input 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.

• 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 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. Check the Status of the "Remote PTO Set Switch" and the "Remote PTO Resume Switch"

Illustration 7	g00644513
ECM Breakout T-connector

1. Turn the ignition key switch to the OFF position.

2. Fabricate a jumper wire 100 mm (4 inch) long. Crimp a Deutsch pin to each end of the wire.

3. Disconnect vehicle harness connector P1 from the ECM.

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

5. Connect Cat ET to the data link connector.

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

7. Access the "Remote PTO Set Switch" and "Remote PTO Resume Switch" status on Cat ET.

8. While the remote PTO set switch status is being observed on Cat ET, install the jumper into the breakout T in order to connect terminal 58 (INPUT 2) to terminal 3 (Input Sensor Common #2). Also, while the switch status is being observed on Cat ET, remove the jumper from the breakout T in order to disconnect terminal 58 (INPUT 2) from terminal 3 (Input Sensor Common #2).

9. While the remote PTO resume switch status is being observed on Cat ET, install the jumper into the breakout T in order to connect terminal 60 (INPUT 3) to terminal 3 (Input Sensor Common #2). Also, while the switch status is being observed on Cat ET, remove the jumper from the breakout T in order to disconnect terminal 60 (INPUT 3) from terminal 3 (Input Sensor Common #2).

   The Input 2 is the set switch for the PTO and the Input 3 is the resume switch for the PTO.

   Refer to Illustration 7.

Expected Result:

The switch status of the "Remote PTO Set Switch" on Cat ET 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 terminal 58 (INPUT 2) to terminal 3 (Input Sensor Common #2).

The switch status of the "Remote PTO Resume Switch" on Cat ET 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 terminal 60 (INPUT 3) to terminal 3 (Input Sensor Common #2).

Results:

• OK - The Input 2 (Remote PTO Set) and the Input 3 (Remote PTO Resume) 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.

• 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 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.