On-Highway Engines Electronic PTO Installation and Application Guide Caterpillar

Use this procedure under the following situation:

The PTO shutdown is suspected of incorrect operation.

The following background information is related to this procedure:

PTO Shutdown Timer

A programmable parameter for the PTO shutdown timer is provided. This timer will shut down the engine when all of the following conditions are met:

• The PTO shutdown time that is programmed has expired.

• The Engine Control Module (ECM) is programmed to use dedicated PTO parameters.

• The PTO on/off switch is on and the ECM is in the dedicated PTO mode.

• The engine is not in the cold mode.

During the last 90 seconds of the PTO shutdown timer, the check engine lamp will begin flashing. If the vehicle is equipped with a PTO switch on lamp, the PTO switch on lamp will begin flashing during the last 90 seconds.

If the PTO shutdown timer is activated and the timer stops the engine, the following event code will be generated.

• 71-14 (47)

Note: Fuel rates are not monitored while the PTO shutdown timer is active. Shutdown will occur regardless of load. Unlike the idle shutdown timer, the PTO shutdown timer cannot be overridden by using the clutch pedal or the brake pedal.

The following note pertains to the heavy-duty engines ( C-10, C11, C-12, C13, 3406E, C15, C-15, C-16, and C-18).

Note: With OCT99 and newer software, an additional parameter can be programmed to allow the timer to be reset above a specified engine speed. When the parameter for the "PTO Shutdown Timer Maximum RPM" is programmed to a value below the top engine limit, the timer can be reset by increasing engine rpm above a programmed limit. The timer will stay reset until engine rpm drops below the programmed value. At this point, the timer will begin to count again. The factory default setting of 2120 rpm (top engine limit) disables this feature.

Test Step 1. Verify Activation of the PTO Shutdown Timer

1. Connect Caterpillar Electronic Technician (ET) to the data link connector.

2. Access the customer parameters on Cat ET. Access the following display screens in order:
   • "Service"

   • "Configuration"

   1. Record the programmed PTO shutdown time. The PTO shutdown time must be between 3 and 1440 minutes. If the PTO shutdown time is programmed to zero, the timer is disabled.

3. Start the engine. Allow the engine to warm up until the coolant temperature is 38 °C (100 °F). Allow the engine to operate at the programmed low idle and turn off any unnecessary accessory devices.

4. Ensure that all unnecessary loads are turned off.

5. Use the following procedure in order to check the operation of the PTO shutdown:

   1. Park the vehicle.

   2. Ensure that the PTO configuration is programmed to cab switches, remote switches or remote throttle.

   3. Ensure that the status of the PTO on/off switch is on.

   4. Observe the status of the PTO shutdown.

Note: The following note pertains to the heavy-duty engines ( C-10, C11, C-12, C13, 3406E, C15, C-15, C-16, and C-18). With OCT99 and newer software, a "PTO Shutdown Timer Maximum RPM" can be programmed in order to allow the timer to be reset by increasing engine RPM above the programmed limit. Ensure that the accelerator is not being depressed in order to increase rpm beyond the programmed limit.

Expected Result:

Result 1 The status of the parameter for PTO shutdown indicates "COUNTING".

Result 2 The ECM is not reading the proper conditions for activation of the timer.

Results:

• Result 1 - The ECM is reading the proper conditions for the activation of the PTO shutdown timer. Proceed to Test Step 2.

• Result 2 - The ECM is not reading the proper conditions for activation of the timer. Proceed to Test Step 3.

Test Step 2. Verify the Driver Alert Function of the PTO Shutdown

1. Verify that Cat ET is connected to the data link connector.

2. Use the following procedure in order to activate the PTO shutdown timer:

   1. Access the customer parameters on Cat ET. Access the following display screens in order:
      • "Service"

      • "Configuration"

   2. Record the programmed PTO shutdown time. The PTO shutdown time must be between 3 and 1440 minutes. If the PTO shutdown time is programmed to zero, the timer is disabled.

   3. Reprogram the PTO shutdown time to three minutes for this test.

3. Observe the following items during the 90 second period before the programmed shutdown time:
   • Check engine lamp

   • Status of the PTO shutdown timer

   • PTO switch on lamp

   While the engine is in the last 90 second period before the scheduled shutdown, the status should change from "COUNTING" to "DRIVER ALERT" and the check engine lamp and the PTO switch on lamp should flash rapidly.

   Note: A PTO switch on lamp is an optional feature and the PTO switch on lamp may not be installed.

4. Reprogram the PTO shutdown timer to the value that was recorded earlier for this test.

Expected Result:

Result 1 The driver alert function of the PTO shutdown operates in the manner that is described above.

Result 2 The PTO switch on lamp did not flash.

Result 3 The check engine lamp did not flash.

Results:

• Result 1 - The PTO shutdown timer is operating properly. Clear all diagnostic codes.STOP

• Result 2 - "PTO Switch On Lamp" did not flash during the driver alert.

  Repair: Perform the following diagnostic procedure: Troubleshooting, "PTO Switch ON Lamp Circuit - Test"

  STOP

• Result 3 - The check engine lamp did not flash during the driver alert.

  Repair: Perform the following diagnostic procedure:Troubleshooting, "Check Engine Lamp Circuit - Test"

  STOP

Test Step 3. Check the State of the Related Conditions When the Vehicle is Parked

1. Check the state of the following related conditions when the vehicle is parked:

   1. Ensure that the vehicle speed is 0 km/h (0 mph) on Cat ET or the dash display.

   2. Ensure that the engine is not in cold mode.

      Note: The status screen on Cat ET will indicate if the cold mode is active.

   3. Ensure that the PTO on/off switch is on.

Expected Result:

Result 1 Vehicle speed is not indicated as 0 km/h (0 mph).

Result 2 The status screen on Cat ET indicates that the engine is in the cold mode.

Result 3 The PTO on/off switch is not on.

Results:

• Result 1 - Vehicle speed is not indicated as 0 km/h (0 mph). Continue by testing the vehicle speed circuit.

  Repair: Perform the following diagnostic procedure: Troubleshooting, "Vehicle Speed Circuit - Test"

  STOP

• Result 2 - The status screen on Cat ET indicates that the engine is in the cold mode. The engine must not be in cold mode operation while this test procedure is being performed. Allow the engine to run until the coolant temperature exceeds 38 °C (100 °F). Troubleshoot and repair any related conditions. STOP

• Result 3 - The PTO on/off switch is not on. Continue by testing the circuit for the PTO on/off switch.

  Repair: Perform the following diagnostic procedure: Troubleshooting, "PTO Switch Circuit - Test"

  STOP