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

Illustration 1	g00725429
The left side of the C-15 truck engine is shown. (1) Vehicle harness connector J1/P1 (2) Engine harness connector J2/P2 (3) Engine Control Module (ECM) (4) ECM side of vehicle harness connector P1 (5) Side view of vehicle harness connector P1 (6) Harness side of vehicle harness connector P1

Considerations for the Installation

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The switches labeled "PTO Interlock" in the schematics are redundant and should be added to ensure the engine is put in PTO mode only when the vehicle and operator are prepared for safe PTO operation. The interlocks must prevent operation of the engine PTO until the PTO operator is expecting it and is prepared. These switch(es) may be (parking brake switch or other switches) available as an interlock and are required for the application.

PTO Switch On Lamp

The PTO switch On lamp should be installed in the cab. If the PTO operating station is outside of the cab, a lamp should also be installed at the operating station. This lamp will provide an indication to the driver/PTO operator when the PTO On/Off circuit is ON. Refer to the appropriate diagrams for the application. The "PTO switch On lamp" parameter must be programmed to J1/P1:30 in order for Output 1 to illuminate the PTO switch On lamp when the PTO On/Off switch is in the ON position. If the "PTO Configuration" is programmed to Cab Switches, then refer to Illustrations 4 and 5. If the "PTO Configuration" is programmed to "Remote Switches", then refer to Illustrations 6 and 7. If the "PTO Configuration" is programmed to "Remote Throttle", then refer to Illustrations 8 and 9.

The "PTO Configuration" is Programmed to "Remote Switches" or to "Remote Throttle"

The components that follow are ignored when the PTO On/Off circuit is in the ON position. The "PTO Configuration" must also be programmed to "Remote Switches" or to "Remote Throttle": accelerator pedal position sensor for the cab, clutch switch, service brake switch and cruise control switches. A PTO Switch On lamp is recommended in both the cab and at the remote station in order to indicate when the PTO On/Off circuit is ON. The Parking Brake Switch and/or a Transmission Neutral Switch causes the engine to return to the "Low Idle Engine RPM". The engine will return to the "Low Idle Engine RPM" if someone tries to move the vehicle and the operator of the PTO is at the remote location. The "Idle/PTO Vehicle Speed Limit" should also be programmed to the minimum 1 km/h (1 mph) in order to cause the engine to return to low idle if the vehicle is moved.

Engine Shutdown Switch

If an engine shutdown switch is desired, then the switch should be connected to a Normally Closed Relay. Refer to Schematic 2 for an example. The actual location of the switch should be readily accessible to the operator of the PTO during PTO operation.

Schematic for the Engine Shutdown Switch

Illustration 2	g00627399
Schematic for the engine shutdown switch for a full feature system

PTO Interlocks for Transmission Driven PTO

Any PTO Configuration

Vehicles that use a transmission driven PTO require an additional Parking Brake Interlock Switch for the PTO On/Off circuit. The interlock will prevent PTO operation if the Parking Brake is not set.

Illustration 3	g00716284
Schematic for the PTO Interlock for transmission driven PTO

Installation for Three PTO Configurations

The "PTO configuration" provides three programmable options:

• "Cab switches"

• "Remote switches"

• "Remote throttle"

The information in this section provides details on the installation of the necessary components that are required for the various options for the "PTO configuration".

"Cab Switches" PTO Configuration

No splicing into the existing cab wiring is necessary. The Cruise Control Set/Resume Switch is used for PTO Operation, Cruise Control, and Extended Idle. The function of the Set position and Resume position is determined by the programming of the following parameters: "PTO Engine RPM Set Speed", "Cruise/Idle/PTO Switch Configuration" and "Idle/PTO Bump RPM"

The Set position becomes the RPM increase position and the Resume position becomes the RPM decrease position if the "PTO Engine RPM Set Speed" is programmed above 0 rpm. If the "PTO Engine RPM Set Speed" is programmed to 0 rpm, then the Set position can provide either the ACCEL or the DECEL function and the Resume position can provide either the DECEL function or the ACCEL function. A programmable bump rpm is determined by the "Idle/PTO Bump RPM" parameter.

Note: A Neutral Switch (Input 12, J1/P1 terminal-62) is required for PTO operation if the PTO Configuration is programmed to "Cab Switches" and the "Transmission Style" is programmed to one of the following options: "Automatic Option 3" and "Automatic Option 4".

Illustration 4	g00717912
"Cab Switches" for "PTO Configuration" (A) Set/Resume switch (B) PTO On/Off switch (C) PTO Switch On lamp (D) ECM side of vehicle harness connector J1 (E) Harness side of vehicle harness connector P1 (3) "Input sensor common 2" (30) "Output 1" (PTO Switch On lamp) (56) "Input 1" (PTO On/Off switch)

Illustration 5	g00716285
Schematic for "Cab Switches" for "PTO Configuration"

"Remote Switches" PTO Configuration

The Cruise Control Set/Resume switch that is in the cab is not used. "Remote switches PTO configuration" requires the installation of a remote set switch and the installation of a remote resume switch. While the PTO is in operation, all of the cab controls will be ignored.

The function of the Set position and Resume position is determined by the programming of the "PTO Engine RPM Set Speed", "Cruise/Idle/PTO Switch Configuration", and the "Idle/PTO Bump RPM" parameters.

The Set position becomes the RPM increase position and the Resume position becomes the RPM decrease position if the PTO Engine RPM Set Speed is programmed above 0 rpm. If the "PTO Engine RPM Set Speed" is programmed to 0 rpm, then the Set position can provide either the ACCEL or the DECEL function and the Resume position can provide either the DECEL function or the ACCEL function. A programmable bump rpm is determined by the "Idle/PTO Bump RPM" parameter.

Illustration 6	g00716286
"Remote Switches" for "PTO Configuration" (A) PTO On/Off Switch (B) The PTO Set/Resume switch may be located in the cab or in a remote location. The operation of the PTO Set/Resume switch is dependent upon the programming. (C) PTO Switch On lamp (D) PTO Switch On lamp (E) ECM side of the vehicle harness connector J1 (F) Harness side of the vehicle harness connector P1 (3) "Input sensor common 2" (30) "Output 1" (PTO switch On lamp) (56) "Input 1" (PTO On/Off switch) (58) "Input 2" (PTO set switch) (60) "Input 3" (PTO resume switch)

Illustration 7	g00716287
Schematic for "Remote Switches" for "PTO Configuration"

"Remote Throttle" PTO Configuration

The ECM monitors the Remote Accelerator Position Sensor when the PTO On/Off switch and the PTO Interlock switches are closed. The PTO Set switch can be used to set engine rpm and the PTO Resume switch is available to resume a previously set RPM. The switch will go to the ACCEL position or the switch will go to the DECEL position from the current set speed if the PTO Set switch is held in position or the PTO Resume switch is held in position. This is based on the programming for the customer specified parameter.

Illustration 8	g00716289
"Remote Throttle" for "PTO Configuration" (A) PTO Switch On lamp (B) PTO On/Off Switch (C) The PTO Set/Resume switch may be located in the cab or in a remote location. The operation of the PTO Set/Resume switch is dependent upon the programming. (D) PTO Switch On lamp (E) PTO accelerator assembly (F) ECM side of the vehicle harness connector J1 (G) Harness side of the vehicle harness connector P1 (3) "Input sensor common 2" (30) "Output 1" (PTO switch On lamp) (56) "Input 1" (PTO On/Off switch) (58) "Input 2" (PTO set switch) (60) "Input 3" (PTO resume switch) (68) "Input 8" (remote accelerator)

Illustration 9	g00716290
Schematic for the "Remote Throttle" for "PTO Configuration"

"Cab Switches" with Torque Limit Switch

When the Torque Limit switch is in the ON position, the "Torque Limit" is applicable. The "Torque Limit" is used when the "Torque Limit" has a programmed value and the PTO On/Off switch is in the ON position. The "Torque Limit" is operational when driving the vehicle and the PTO On/Off switch is in the OFF position. For example, this is useful when the transmission provides deep reduction gears that require reduced torque levels for the driveline. This feature should only be used for temporary protection of the equipment. To enable this feature, "Input 4" must be programmed to "Torque Limit Switch". The default is "None".

Illustration 10	g00716420
Configuration of the "Cab Switches" with torque limit switch (A) PTO Set/Resume switch (B) PTO On/Off Switch (C) PTO Switch On lamp (D) Torque limit switch (E) ECM side of the vehicle harness connector J1 (F) Harness side of the vehicle harness connector P1 (3) "Input sensor common 2" (7) "Input 4" (torque limit switch) (30) "Output 1" (PTO switch On lamp) (56) "Input 1" (PTO On/Off switch)

Illustration 11	g00716421
Schematic for the "Cab Switches" with torque limit switch

"Cab Switches" with Ignore Brake/Clutch Switch

The Ignore Brake/Clutch switch is intended for applications that require mobile use of the vehicle with a set engine rpm. The PTO will disengage if the brake is depressed or if the clutch is depressed. The Ignore Brake/Clutch switch prevents the clutch or the brake from disengaging the PTO set speed. This is useful for the following applications: fire truck, cement pavement and curb pouring operations. In order to enable this feature, "Input 5" must be programmed to "Ignore Brake/Clutch Switch". The default is "None".

Note: If the "Transmission Style" is programmed to "Automatic Option 3" or to "Automatic Option 4", then provisions must be taken in order to prevent the neutral switch from disengaging the PTO when the transmission is in gear.

Illustration 12	g00716434
Configuration of the "Cab Switches" with ignore brake/clutch switch (A) PTO Set/Resume switch (B) PTO On/Off Switch (C) PTO Switch On lamp (D) Ignore brake/clutch switch (E) ECM side of the vehicle harness connector J1 (F) Harness side of the vehicle harness connector P1 (3) "Input sensor common 2" (30) "Output 1" (PTO switch On lamp) (47) "Input 5" (ignore brake/clutch switch) (56) "Input 1" (PTO On/Off switch)

Illustration 13	g00716435
Schematic for "Cab Switches" with ignore brake/clutch switch

"Remote Switches" with Torque Limit Switch

The "Torque Limit" is used when the "Torque Limit" has a programmed value and the PTO On/Off switch is in the ON position. The diagrams illustrate the connection of a second switch in order to provide the "Torque Limit" under certain conditions. The "Torque Limit" is operational when driving and the PTO On/Off switch is in the OFF position. For example, this is useful when the transmission provides deep reduction gears that require reduced torque levels for the driveline. This feature should only be used for temporary protection of the equipment. To enable this feature, "Input 4" must be programmed to "Torque Limit Switch". The default is "None".

Illustration 14	g00716422
Configuration for "Remote Switches" with torque limit switch (A) PTO On/Off Switch (B) PTO Set/Resume switch (C) PTO Switch On lamp (D) PTO Switch On lamp (E) Torque limit switch (F) ECM side of the vehicle harness connector J1 (G) Harness side of the vehicle harness connector P1 (3) "Input sensor common 2" (7) "Input 4" (torque limit switch) (30) "Output 1" (PTO switch On lamp) (56) "Input 1" (PTO On/Off switch) (58) "Input 2" (PTO set switch) (60) "Input 3" (PTO resume switch)

Illustration 15	g00716424
Schematic for "Remote Switches" with torque limit switch

"Remote Switches" with Ignore Brake/Clutch Switch

All inputs from the cab are ignored when the "Remote Switches PTO Configuration" is programmed. The Ignore Brake/Clutch switch is used to ignore the following inputs: brake and clutch. The inputs are ignored while in idle mode. This is for applications that require mobile use of the vehicle with a set engine rpm that does not require the brake or clutch to disengage the idle set speed. To enable this feature, "Input 5" must be programmed to "Ignore Brake Clutch Switch".

If the PTO On/Off switch is OFF, then the ECM considers the closure of the ignore brake/clutch switch as a request to prevent the disengagement of the idle set speed. The vehicle speed must be below the programmable "Idle Vehicle Speed Limit" and an engine rpm must be set for the feature to be applicable. The ignore brake/clutch switch is not required when the PTO On/Off switch is in the ON position. All cab inputs are ignored.

Note: If the "Transmission Style" is programmed to "Automatic Option 3" or to "Automatic Option 4", then provisions must be taken in order to prevent the neutral switch from disengaging the idle set speed when the transmission is in gear.

Illustration 16	g00716427
Configuration for "Remote Switches" with ignore brake/clutch switch (A) PTO On/Off Switch (B) PTO Set/Resume switch (C) PTO Switch On lamp (D) PTO Switch On lamp (E) Torque limit switch (F) Ignore Brake/Clutch switch (G) ECM side of the vehicle harness connector J1 (H) Harness side of the vehicle harness connector P1 (3) "Input sensor common 2" (30) "Output 1" (PTO switch On lamp) (47) "Input 5" (Ignore Brake/Clutch switch) (56) "Input 1" (PTO On/Off switch) (58) "Input 2" (PTO set switch) (60) "Input 3" (PTO resume switch)

Illustration 17	g00716429
Schematic for "Remote Switches" with Ignore Brake/Clutch switch

Idle Shutdown is Disabled with the PTO Switch ON

The ECM will disable the Idle Shutdown Timer when the circuit for the PTO On/Off switch is in the ON position. This will prevent shutdowns that are unwanted when the PTO mode is active. The PTO Shutdown Timer can be used to shut down the engine. This shutdown can be used if the driver/operator is using the PTO mode in order to prevent idle shutdown. The PTO Shutdown Timer will shut down the engine but the PTO Shutdown Timer will not disable the ECM.

Note: It is critical that the operator of the PTO knows the arrangement. The operator must fully understand the setup of the PTO system. It is also critical that the operator of the PTO understands the operation of the system.

"Multiple Speed PTO Operation" That Uses The "PTO Engine RPM Set Speed Input A" and The "PTO Engine RPM Set Speed Input B"

The "Multiple Speed PTO Operation" that uses the "PTO Engine RPM Set Speed Input A" and the "PTO Engine RPM Set Speed Input B" is available for use with all three PTO configurations. The engine will operate at the programmed "PTO Engine RPM Set Speed A" when the PTO Engine RPM Set Speed Input A switch (Input 7) and the PTO On/Off switch are ON. The engine will operate at the "PTO Engine RPM Set Speed B" when the PTO Engine RPM Set Speed Input B switch (Input 19) and the PTO On/Off switch are ON. The "PTO Engine RPM Set Speed B" will not operate unless the PTO Engine RPM Set Speed A switch is OFF. The "PTO Engine RPM Set Speed Input A" and the "PTO Engine RPM Set Speed Input B" have priority over all of the other features that are used to control the engine speed during PTO operation. The exception is any circumstance that causes the PTO operation to be disabled.

Illustration 18	g00719704
Configuration for the "Multiple Speed PTO Operation" that uses the "PTO Engine RPM Set Speed Input A" and the "PTO Engine RPM Set Speed Input B" (A) PTO Set/Resume switch (B) PTO On/Off Switch (C) PTO Switch On lamp (D) PTO Engine RPM Set Speed B On/Off Switch (E) PTO Engine RPM Set Speed A On/Off Switch (F) ECM side of the vehicle harness connector J1 (G) Harness side of the vehicle harness connector P1 (3) "Input sensor common 2" (23) "Input 19 (PTO Engine RPM Set Speed B switch)" (30) "Output 1" (PTO switch On lamp) (46) "Input 7" (PTO Engine RPM Set Speed A switch) (56) "Input 1" (PTO On/Off switch)

Illustration 19	g00719705
Schematic for the "Multiple Speed PTO Operation" that uses the "PTO Engine RPM Set Speed Input A" and the "PTO Engine RPM Set Speed Input B"