C9 Engine for the 816F Series 2 Landfill Compactor, the 815F Series 2 Soil Compactor, and the 814F Series 2 Wheel Dozer Caterpillar

Use this procedure to troubleshoot the electrical system if the diagnostic code in Table 1 is active or easily repeated.

The "Throttle Lock with Throttle Backup" allows the operator to maintain a desired engine speed without the use of the throttle pedal.

The throttle lock feature uses three switches and the right brake pedal for inputs to the engine ECM:

Throttle Lock Switch - This is a rocker switch that is used to enable the throttle lock feature. No diagnostics are performed on this switch input.

Right Brake Pedal - The right brake pedal switch is a double-pole single-throw switch. The switch is used to disengage the engine speed from the throttle lock's engine speed setpoint while the throttle lock feature is being used. When the right brake pedal is used to disengage the engine speed from the setpoint, the setpoint is stored in ECM memory. The engine speed can be reset to the setpoint by the operator's use of the resume switch. Two switch inputs are used to monitor the status of the right brake pedal. One input is normally open while the other input is normally closed. Diagnostic codes are available for the right brake pedal switch.

Set/Decel Switch - The Set/Decel switch can be used to establish the setpoint for the throttle lock feature. The switch can also be used to lower a setpoint that has already been established. The Set/Decel switch can be depressed in order to establish the setpoint for the throttle lock feature. The throttle pedal is used to establish the desired engine speed. The setpoint for the throttle lock may be viewed on the service tool status screen. When a setpoint is established, the operator may depress the Set/Decel switch in order to decrease the engine speed. When the switch is bumped, the engine speed will decrease by 20 rpm. Hold the switch in order to decrease the engine speed at a rate of 50 rpm per second. The operator may use the throttle pedal to increase the engine speed beyond the set point. No diagnostics are performed on this switch input.

Resume/Accel Switch - The Resume/Accel switch can be used to resume a previous set point. The Resume/Accel switch can also be used to increase an already established set point. If the right brake pedal has been used to disengage the engine speed from the setpoint for the throttle lock, the operator may press the Resume/Accel switch in order to resume the previous setpoint. The right brake pedal must be released in order to resume the setpoint. The previous set point will only exist if the right brake pedal or the engine retarder has been used to disengage throttle lock. When the resume switch is pressed, the desired engine speed will accelerate to the previous set point at a rate of 2000 rpm per second. The previous setpoint is cleared from memory if the throttle lock switch has been turned to the OFF position, or if the ECM has been powered down. Once a set point is established, the operator may depress the Resume/Accel switch in order to increase the engine speed by 20 rpm. The switch can be held in order to increase the engine speed at a rate of 50 rpm per second. No diagnostics are performed on this input.

The throttle lock feature also provides a throttle backup. If the throttle sensor fails, the engine speed will default to low idle. While the throttle lock feature is enabled, the Set/Decel switch and the Resume/Accel switch can be used to fully control the engine speed.

If a diagnostic code for the right brake pedal becomes active, the throttle lock feature will be disabled. The power must be cycled in order to enable the throttle lock feature. The engine will still respond to the throttle pedal.

Illustration 1	g01342126
Schematic for the throttle lock feature

Test Step 1. Inspect Electrical Connectors and Wiring

1. Turn the keyswitch to the OFF position.

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Illustration 2	g01343069
Locations of the ECM connectors for the throttle lock feature (1) J1/P1 ECM connectors (2) Machine interface connectors (25-Pin) (3) Machine interface connectors (20-Pin)

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Illustration 3	g01343057
Locations of the components in the cab of the machine for the throttle lock feature (4) Right brake pedal (5) Throttle pedal (6) Throttle lock switch (7) Set/decel switch (8) Resume/accel switch

2. Thoroughly inspect ECM connectors (1), machine connectors 2 and 3, the switch for right brake pedal (4), the sensor for throttle pedal (5), the throttle lock switch (6), the Set/Decel switch (7), and the Resume/Accel switch (8). Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.

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Illustration 4	g01342635
Terminal locations at the P1 ECM connector for the throttle lock switch (P1-5) Digital return (P1-35) Set/decel switch (P1-41) Throttle lock's on/off switch (P1-44) Right brake pedal switch (N/O) (P1-45) Right brake pedal switch (N/C) (P1-59) Resume/accel switch

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Illustration 5	g01343071
Terminal locations at the machine interface connector (25-Pin) (Terminal 2) Throttle lock's Set/Decel switch (Terminal 3) Throttle lock's Resume/Accel switch (Terminal 5) Throttle lock switch (on/off)

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Illustration 6	g01343072
Terminal locations at the machine interface connector (20-Pin) (Terminal 10) Right brake pedal switch (N/C) (Terminal 11) Right brake pedal switch (N/O) (Terminal 12) Digital return

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Illustration 7	g01342639
Terminal locations at the throttle lock's on/off switch (Terminal 2) Digital return (Terminal 3) Throttle lock (on/off)

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Illustration 8	g01342848
Terminal locations at the Set/Decel switch (Terminal A) Digital return (Terminal C) Set/decel

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Illustration 9	g01342868
Terminal locations at the Resume/Accel switch (Terminal A) Digital return (Terminal C) Resume/accel

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Illustration 10	g01342877
Location of the right brake pedal and terminal locations for the connector at the right brake pedal switch (Terminal A) Digital return (Terminal B) Right brake pedal switch (N/C) (Terminal C) Right brake pedal switch (N/O)

3. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connectors that are associated with the circuit.

4. Check the allen head screw for each of the ECM connectors for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.

5. Check the harness and wiring for abrasion and for pinch points.

Expected Result:

All connectors, pins and sockets are completely coupled and/or inserted and the harness and wiring are free of corrosion, of abrasion and of pinch points.

Results:

• OK - The harness and connectors appear to be OK. Proceed to Test Step 2.

• Not OK - There is a problem with the connectors and/or wiring.

  Repair: 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 2. Check for Active Diagnostic Codes

1. Connect Caterpillar Electronic Technician (ET) to the service tool connector.

2. Turn the keyswitch to the ON position. Start the engine.

3. Monitor the active diagnostic code screen on Cat ET. Check and record any active diagnostic codes. Look for the following diagnostic code:
   • 298-2

   Note: Wait at least 30 seconds in order for the diagnostic codes to become active.

Expected Result:

No diagnostic codes are active.

Results:

• OK - No diagnostic code is active. There may be a problem with one of the other switches in the circuit. Proceed to Test Step 4.

• Not OK - A 298-2 diagnostic code is active at this time. There is a problem with the right brake pedal switch. Proceed to Test Step 3.

Test Step 3. Short the Circuit at the Connector for the Right Brake Pedal Switch and Check the Switch Status on Cat ET

1. Disconnect the connector for the right brake pedal switch at the switch.

2. Fabricate a jumper wire that is long enough to create a short circuit across the harness connector for the right brake pedal switch. Crimp connector pins to each end of the jumper wire.

3. Install the jumper wire across terminal A (digital return) and terminal B (right brake pedal switch (N/C)) on the harness side of the connector for the right brake pedal switch.

4. Turn the keyswitch to the ON position.

5. Observe the status of the "Right Brake Pedal Switch" on Cat ET.

   Note: Wait at least 30 seconds in order for the status of the switch to change.

   The correct status of the switch is "Released".

6. Install the jumper wire across terminal A (digital return) and terminal C (right brake pedal switch (N/O)) of the harness side of the connector for the right brake pedal switch.

7. Observe the status of the "Right Brake Pedal Switch" on Cat ET.

   Note: Wait at least 30 seconds in order for the status of the switch to change.

   The correct status of the switch is "Depressed".

8. Turn the keyswitch to the OFF position. Restore the wiring to the original configuration.

Expected Result:

The correct status of the switch is observed.

Results:

• OK - The correct status of the switch is observed. There may be a problem with one of the other switches in the circuit. Proceed to Test Step 4.

• Not OK - The correct status of the switch was not observed during the test procedure. There is a problem in the wiring harness for the right brake pedal switch. There may be a problem with the ECM. Proceed to Test Step 7.

Test Step 4. Short the Circuit at the Connector for the Throttle Lock's On/Off Switch and Check the Switch Status on Cat ET

1. Disconnect the connector for the throttle lock switch at the switch.

2. Fabricate a jumper wire that is long enough to create a short circuit across the harness connector for the throttle lock switch. Crimp spade terminals to each end of the jumper wire.

3. Install the jumper wire across terminal 2 (digital return) and terminal 3 (throttle lock switch (on/off)) on the harness side of the connector for the right brake pedal switch.

4. Turn the keyswitch to the ON position.

5. Observe the status of the "Throttle Lock Switch" on Cat ET.

   Note: Wait at least 30 seconds in order for the status of the switch to change.

   The correct status of the switch is "On".

6. Remove the jumper wire from the connector terminals.

7. Observe the status of the "Throttle Lock Switch" on Cat ET.

   Note: Wait at least 30 seconds in order for the status of the switch to change.

   The correct status of the switch is "Off".

8. Turn the keyswitch to the OFF position. Restore the wiring to the original configuration.

Expected Result:

The correct status of the switch is observed.

Results:

• OK - The correct status of the switch is observed. There may be a problem with one of the other switches in the circuit. Proceed to Test Step 5.

• Not OK - The correct status of the switch was not observed during the test procedure. There is a problem in the wiring harness for the throttle lock's on/off switch. There may be a problem with the ECM. Proceed to Test Step 7.

Test Step 5. Short the Circuit at the Connector for the Throttle Lock's Set/Decel Switch and Check the Switch Status on Cat ET

1. Disconnect the connector for the Set/Decel switch at the switch.

2. Fabricate a jumper wire that is long enough to create a short circuit across the harness connector for the Set/Decel switch. Crimp connector pins to each end of the jumper wire.

3. Install the jumper wire across terminal A (digital return) and terminal C (Set/Decel switch) on the harness side of the connector for the Set/Decel switch.

4. Turn the keyswitch to the ON position.

5. Observe the status of the "Throttle Set/Decel Switch" on Cat ET.

   Note: Wait at least 30 seconds in order for the status of the switch to change.

   The correct status of the switch is "On".

6. Remove the jumper wire from the connector terminals.

7. Observe the status of the "Throttle Set/Decel Switch" on Cat ET.

   Note: Wait at least 30 seconds in order for the status of the switch to change.

   The correct status of the switch is "Off".

8. Turn the keyswitch to the OFF position. Restore the wiring to the original configuration.

Expected Result:

The correct status of the switch is observed.

Results:

• OK - The correct status of the switch is observed. There may be a problem with one of the other switches in the circuit. Proceed to Test Step 6.

• Not OK - The correct status of the switch was not observed during the test procedure. There is a problem in the wiring harness for the throttle lock's Set/Decel switch. There may be a problem with the ECM. Proceed to Test Step 7.

Test Step 6. Short the Circuit at the Connector for the Throttle Lock's Resume/Accel Switch and Check the Switch Status on Cat ET

1. Disconnect the connector for the Resume/Accel switch at the switch.

2. Fabricate a jumper wire that is long enough to create a short circuit across the harness connector for the Set/Decel switch. Crimp connector sockets to each end of the jumper wire.

3. Install the jumper wire across terminal A (digital return) and terminal C (Resume/Accel switch) on the harness side of the connector for the Resume/Accel switch.

4. Turn the keyswitch to the ON position.

5. Observe the status of the "Throttle Res/Accel Switch" on Cat ET.

   Note: Wait at least 30 seconds in order for the status of the switch to change.

   The correct status of the switch is "On".

6. Remove the jumper wire from the connector terminals.

7. Observe the status of the "Throttle Set/Decel Switch" on Cat ET.

   Note: Wait at least 30 seconds in order for the status of the switch to change.

   The correct status of the switch is "Off".

8. Turn the keyswitch to the OFF position. Restore the wiring to the original configuration.

Expected Result:

The correct status of the switch is observed.

Results:

• OK - The correct status of the switch is observed.

  Repair: The throttle lock's Resume/Accel switch appears to be operating properly at this time. Also, all of the other switches for the throttle lock feature appear to be operating properly at this time. There may be an intermittent problem in the harness or in one of the connectors. If an intermittent problem is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect".

  STOP

• Not OK - The correct status of the switch was not observed during the test procedure. There is a problem in the wiring harness for the throttle lock's Resume/Accel switch. There may be a problem with the ECM. Proceed to Test Step 7.

Test Step 7. Check for the Proper Operation of the ECM

1. Disconnect the J1/P1 ECM connectors.

2. Fabricate a jumper wire that is long enough to create a test circuit across the ECM connector.

3. Remove the wire from terminal location P1-5 (digital return) at the ECM connector. Install the jumper wire into this terminal location.

4. Perform the following procedure in order to test the circuit for the right brake pedal switch at the ECM:

   1. Fabricate two additional jumper wires that are long enough to create a test circuit across the ECM connector. Crimp connector sockets to one end of each of the jumper wires.

   2. Remove the wires from terminal locations P1-44 (right hand brake pedal (N/O)) and P1-45 (right hand brake pedal (N/C)) at the ECM connector. Install the jumper wires into these terminal locations.

   3. Connect the J1/P1 ECM connectors.

   4. Short circuit the jumper wires in terminal locations P1-5 and P1-45.

   5. Turn the keyswitch to the ON position.

   6. Observe the status of the "Right Brake Pedal Switch" on Cat ET.

      Note: Wait at least 30 seconds in order for the status of the switch to change.

      The correct status of the switch is "Released".

   7. Remove the short circuit.

   8. Short circuit the jumper wires in terminal locations P1-5 and P1-44.

   9. Observe the status of the "Right Brake Pedal Switch" on Cat ET.

      Note: Wait at least 30 seconds in order for the status of the switch to change.

      The correct status of the switch is "Depressed".

   10. Turn the keyswitch to the OFF position.

5. Perform the following procedure in order to test the circuit for the throttle lock's on/off switch at the ECM:

   1. Fabricate an additional jumper wire that is long enough to create a test circuit across the ECM connector. Crimp a connector socket to one end of the jumper wire.

   2. Remove the wire from terminal location P1-41 (throttle lock (on/off) switch) at the ECM connector. Install the jumper wire into this terminal location.

   3. Connect the J1/P1 ECM connectors.

   4. Short circuit the jumper wires in terminal locations P1-5 and P1-41.

   5. Turn the keyswitch to the ON position.

   6. Observe the status of the "Throttle Lock Switch" on Cat ET.

      Note: Wait at least 30 seconds in order for the status of the switch to change.

      The correct status of the switch is "On".

   7. Remove the short circuit.

   8. Do not allow the loose ends of the jumper wires to come into contact with any ground source during this portion of the test.

   9. Observe the status of the "Throttle Lock Switch" on Cat ET.

      Note: Wait at least 30 seconds in order for the status of the switch to change.

      The correct status of the switch is "Off".

   10. Turn the keyswitch to the OFF position.

6. Perform the following procedure in order to test the circuit for the throttle lock's Set/Decel switch at the ECM:

   1. Fabricate an additional jumper wire that is long enough to create a test circuit across the ECM connector. Crimp a connector socket to one end of the jumper wire.

   2. Remove the wire from terminal location P1-35 (Set/Decel switch) at the ECM connector. Install the jumper wire into this terminal location.

   3. Connect the J1/P1 ECM connectors.

   4. Short circuit the jumper wires in terminal locations P1-5 and P1-35.

   5. Turn the keyswitch to the ON position.

   6. Observe the status of the "Throttle Set/Decel Switch" on Cat ET.

      Note: Wait at least 30 seconds in order for the status of the switch to change.

      The correct status of the switch is "On".

   7. Remove the short circuit.

   8. Do not allow the loose ends of the jumper wires to come into contact with any ground source during this portion of the test.

   9. Observe the status of the "Throttle Set/Decel Switch" on Cat ET.

      Note: Wait at least 30 seconds in order for the status of the switch to change.

      The correct status of the switch is "Off".

   10. Turn the keyswitch to the OFF position.

7. Perform the following procedure in order to test the circuit for the throttle lock's Resume/Accel switch at the ECM:

   1. Fabricate an additional jumper wire that is long enough to create a test circuit across the ECM connector. Crimp a connector socket to one end of the jumper wire.

   2. Remove the wire from terminal location P1-59 (resume/Accel switch) at the ECM connector. Install the jumper wire into this terminal location.

   3. Connect the J1/P1 ECM connectors.

   4. Short circuit the jumper wires in terminal locations P1-5 and P1-59.

   5. Turn the keyswitch to the ON position.

   6. Observe the status of the "Throttle Res/Accel Switch" on Cat ET.

      Note: Wait at least 30 seconds in order for the status of the switch to change.

      The correct status of the switch is "On".

   7. Remove the short circuit.

   8. Do not allow the loose ends of the jumper wires to come into contact with any ground source during this portion of the test.

   9. Observe the status of the "Throttle Set/Decel Switch" on Cat ET.

      Note: Wait at least 30 seconds in order for the status of the switch to change.

      The correct status of the switch is "Off".

   10. Turn the keyswitch to the OFF position.

8. Turn the keyswitch to the OFF position. Restore the wiring to the original configuration.

Expected Result:

The status changes according to the test results that are given above.

Results:

• OK - There is either an open circuit or a short circuit in the wiring between the ECM and the switch.

  Repair: Use continuity checks in order to determine the location of the open or short. Refer to the machine's electrical schematic for the complete electrical circuit.

  STOP

• Not OK - The ECM is not responding to the inputs from the switch.

  Repair: The ECM detects the correct switch status. There is a problem with the ECM. Perform the following procedure:

  1. Temporarily connect a test ECM.

     Refer to Troubleshooting, "ECM - Replace".

  2. Recheck the circuit in order to ensure that the original problem has been resolved.

     If the problem is resolved with the test ECM, install the suspect ECM. If the problem returns with the suspect ECM, replace the ECM. Verify that the problem is resolved.

     If the problem is not resolved with the test ECM, install the original ECM. There is a problem in the wiring.

  STOP