D7 Track-Type Tractor Electrohydraulic Systems Relay - Test Caterpillar


Relay - Test
`
1.1. Machine ECM
2.1. Diagnostic Trouble Code Procedure
3.1. FMI 3
4.1. FMI 5
5.1. FMI 6

Machine ECM

The following is a list of diagnostic codes (DTCs) that are associated with the relay circuits of the machine.

Table 1
Machine ECM (MID 39) 
J1939  CDL  Code Description  System Response 
  444-3  Starter Motor Relay: Voltage Above Normal  Unable to crank the engine of the machine.
Starter will overheat. 
  444-5  Starter Motor Relay: Current Below Normal  Unable to crank the engine of the machine. 
  444-6  Start Motor Relay: Current Above Normal  Unable to crank the engine of the machine. 
  3467-6  Main Power Relay: Current Above Normal  The voltage is outside of the acceptable range, machine will not operate. 

A relay is a component that uses a small amount of electrical current to control the state of a circuit. The circuit is either opened or closed.



Illustration 1g06495752
Schematic of the relay circuits

Note: The preceding diagram is a simplified schematic of the connections for the relays. The schematic is electrically correct. However, not all the possible harness connectors are shown. Refer to the latest revision of the electrical schematic for the specific machine being serviced for the complete schematic.

Diagnostic Trouble Code Procedure

Table 2
Required Tools 
Tool  Part Number  Description  Qty 
T1  146-4080(1)  Digital Multimeter Group 
8T-3224 Needle Tip Group 
7X-1710 Multimeter Probe Group 
8T-8726 Cable Assembly (Three Pin) (3-Pin Breakout) 
T2  JERD2129  Cat® Electronic Technician (Cat ET) 
Windows-based PC 
538-5051 Communication Adapter Gp 
T3  6V-4148  Connector Repair Kit (Sure Seal) 
T4  190-8900  Connector Field Repair Kit (Deutsch) 
T5  175-3700  Connector Repair Kit Deutsch DT 
(1) This multimeter can use an RS232C cable to connect to a Laptop computer or Dataview tool gp for troubleshooting.

Prior to beginning this procedure, inspect the harness connectors that are involved in this circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean, secure, and in good condition. If a problem with a connection is found, correct the problem and verify that the diagnostic code is active before performing a troubleshooting procedure.

  1. Identify the active FMI code associated with the components.

  2. Determine which code is present and use the list below to determine which procedure to follow.

  • FMI 3 diagnostic code, proceed to "FMI 3".

  • FMI 5 diagnostic code, proceed to "FMI 5".

  • FMI 6 diagnostic code, proceed to "FMI 6".

FMI 3

Table 3
Check The Machine Harness For A Short 
Troubleshooting Test Steps  Values  Results 
1. Turn the key start switch and disconnect switch to the OFF position.

2. Disconnect the relay from the harness.

3. Disconnect the ECM machine harness connectors.

4. At the ECM machine harness connector, measure the resistance between the signal contact and all other contacts that are used in the ECM. 
Each resistance measurement is greater than 5KΩ.  Result: All resistance measurements are greater than 5K Ω.

Proceed to "Check If The Diagnostic Code Remains" Table 4.

Result: One or more readings are less than 5 Ω.

Repair: A short exists between the signal contact and the circuit with the low resistance. Repair or replace the machine harness.

Note: A resistance greater than 5 Ω but less than 5K Ω indicates a loose or corroded connection in the circuit. A resistance measurement greater than 5K Ω indicates an open in the circuit.

Proceed to "Check If The Diagnostic Code Remains" Table 4. 

Table 4
Check If The Diagnostic Code Remains 
Troubleshooting Test Steps  Values  Results 
1. Reconnect all harness connectors. Return machine to normal operating condition.

2. Turn the key start switch and the disconnect switch to the ON position.

3. Clear all diagnostic codes.

4. Operate the machine.

5. Stop the machine and engage the safety lock.

6. Check if the diagnostic code is active. 
The diagnostic code is no longer present.  Result: The diagnostic code does not exist currently. The initial diagnostic code may have been caused by poor electrical connection or short at one of the harness connections. Resume machine operation.

STOP.

Result: The diagnostic trouble code has not been corrected. If the diagnostic code has not been corrected after performing the procedure a second time, the ECM may require replacement.

Prior to replacing the ECM, always contact the Technical Communicator at your dealership for possible consultation with AVSpare. This consultation may effect repair time.

For more information refer to the "ECM - Replace" section if the ECM needs to be replaced.

STOP

FMI 5

Table 5
Check The Relay 
Troubleshooting Test Steps  Values  Results 
1. Turn the key start switch and disconnect switch to the OFF position.

2. Disconnect the relay from the wiring harness.

3. At the machine harness connector for the relay, place a jumper wire between the signal wire and the signal return.

4. Turn the key start switch and the disconnect switch to the ON position. Do not start the engine.

5. Observe the status of the diagnostic code. 
The diagnostic code changes from an FMI 5 to an FMI 6 after the jumper wire is installed.  Result: The harness is correct. The diagnostic code changes from an FMI 5 to an FMI 6 after the jumper wire is installed. The relay has failed.

Repair - Replace the relay.

Proceed to "Check If The Diagnostic Code Remains" 7.

Result: The diagnostic code remains active.

Proceed to "Check The Harness For An Open" Table 6. 

Table 6
Check The Harness For An Open 
Troubleshooting Test Steps  Values  Results 
1. Turn key start switch and disconnect switch to the OFF position.

2. Disconnect the machine harness connectors from the ECM.

3. The jumper wire remains installed.

4. At the ECM machine harness connector, measure the resistance between the signal contact and the return contact. 
The resistance is less than 5 Ω.  Result: The resistance is less than 5 Ω. The machine harness is correct.

Proceed to "Check If The Diagnostic Code Remains" 7.

Result: The resistance is greater than 5 Ω. The resistance measurement is not correct. There is an open circuit in the machine harness.

Repair: Repair or replace the machine harness.

Note: A resistance that is greater than 5 Ω but less than 5K Ω would indicate a loose connection or a corroded connection in the circuit. A resistance measurement that is greater than 5K Ω would indicate an open in the circuit.

Proceed to "Check If The Diagnostic Code Remains" 7. 

Table 7
Check If The Diagnostic Code Remains 
Troubleshooting Test Steps  Values  Results 
1. Reconnect all harness connectors. Return machine to normal operating condition.

2. Turn the key start switch and the disconnect switch to the ON position.

3. Clear all diagnostic codes.

4. Operate the machine.

5. Stop the machine and engage the safety lock.

6. Check if the diagnostic code is active. 
The diagnostic code is no longer present.  Result: The diagnostic code does not exist currently. The initial diagnostic code may have been caused by poor electrical connection or short at one of the harness connections. Resume machine operation.

STOP.

Result: The diagnostic trouble code has not been corrected. If the diagnostic code has not been corrected after performing the procedure a second time, the ECM may require replacement.

Prior to replacing the ECM, always contact the Technical Communicator at your dealership for possible consultation with AVSpare. This consultation may effect repair time.

For more information refer to the "ECM - Replace" section if the ECM needs to be replaced.
STOP

FMI 6

Table 8
Check The Relay 
Troubleshooting Test Steps  Values  Results 
1. Turn the key start switch and disconnect switch to the ON position.

2. Observe the status of the diagnostic code.

3. Disconnect the relay from the machine harness. 
The FMI 6 changes to FMI 5 when the relay is disconnected.  Result: FMI 6 changes to FMI 5 when the relay is disconnected. The harness is correct. The relay has failed.

Repair: Repair or replace the relay.

Proceed to "Check If The Diagnostic Code Remains" Table 10.

Result: The diagnostic code remains active.

Proceed to "Check The Return Circuit For A Short To Ground" Table 9. 

Table 9
Check The Return Circuit For A Short To Ground 
Troubleshooting Test Steps  Values  Results 
1. Turn key switch and disconnect switch to the OFF position.

2. The relay remains disconnected from the machine harness.

3. Disconnect the machine harness connectors from the ECM.

4. At the ECM machine harness connector, measure the resistance between the signal contact and all other contacts that are used in the ECM.
 
Each resistance measurement is greater than 5K Ω.  Result: Each resistance measurement is greater than 5K Ω. The machine harness is correct.

Proceed to "Check If The Diagnostic Code Remains" Table 10.

Result: Each resistance measurement is not greater than 5K Ω. A short circuit exists between the signal circuit and the circuit with the low-resistance measurement.

Repair: Repair or replace the machine harness.

Note: A resistance greater than 5 Ω but less than 5K Ω indicates a loose or corroded connection in the circuit. A resistance measurement greater than 5K Ω indicates an open in the circuit.

Proceed to "Check If The Diagnostic Code Remains" Table 10. 

Table 10
Check If The Diagnostic Code Remains 
Troubleshooting Test Steps  Values  Results 
1. Reconnect all harness connectors. Return machine to normal operating condition.

2. Turn the key start switch and the disconnect switch to the ON position.

3. Clear all diagnostic codes.

4. Operate the machine.

5. Stop the machine and engage the safety lock.

6. Check if the diagnostic code is active. 
The diagnostic code is no longer present.  Result: The diagnostic code does not exist currently. The initial diagnostic code may have been caused by poor electrical connection or short at one of the harness connections. Resume machine operation.

STOP.

Result: The diagnostic trouble code has not been corrected. If the diagnostic code has not been corrected after performing the procedure a second time, the ECM may require replacement.

Prior to replacing the ECM, always contact the Technical Communicator at your dealership for possible consultation with AVSpare. This consultation may effect repair time.

For more information refer to the "ECM - Replace" section if the ECM needs to be replaced.

STOP

Information System:

D7 Track-Type Tractor Electrohydraulic Systems ECM Location Code - Test
3512E Locomotive Engines DEF Injector and Mounting - Remove and Install
An Improved Rear Wiper Motor is Now Used on Certain Large Track-Type Tractors {7305}
New Software Is Now Used for Certain C175-16 and C175-20 Locomotive Engines {1920}
More Reliable HVAC Wiring Installation Procedure Is Now Used on Certain Compact Wheel Loaders {7304, 7320, 7332}
A New Cat</SUP> Object Detection Sensor Group (C5 Type) is Now Available for Certain Cat</SUP> Products {7347}
963 Track-Type Loader Machine Systems Joystick Control - Remove and Install - Left Hand
Engine May Overheat on Certain D5 Medium Track-Type Tractors {1386, 1900, 5057}
963 Track-Type Loader Systems Piston Pump Neutral - Test and Adjust
963 Track-Type Loader Systems Crossover Relief Valve - Test and Adjust - Hydrostatic Stall
963 Track-Type Loader Systems Charge Relief Valve - Test and Adjust
963 Track-Type Loader Systems Piston Pump and Motor Maximum Displacement - Test
Improved Piston Motor Groups are Now Used Certain 926M, 930M, 938K, and 938M Wheel Loaders {4351}
963 Track-Type Loader Power Train Track - Separate - SystemOne Track
963 Track-Type Loader Power Train Track - Connect - SystemOne Track
Drain Kit in the Fuel Priming Pump Group May Break on Certain Motor Graders and Wheel loaders {1258, 1260, 1261}
Procedure to Update the Differential Lock Jaws on Certain 620H and 620K Wheel Tractor-Scrapers {3006, 3030, 3159, 3258, 3264, 3284}
D7 Track-Type Tractor Electrohydraulic Systems Sensor Signal (Analog, Active) - Test
Track Guard May Interfere with the Track Link on Certain D5, D6, and D6 XE Track-Type Tractors with Heavy Duty Extended Life (HDXL) Undercarriage {4169, 4171, 4177, 7152}
C32 Engine for 777E Off-Highway Trucks Cylinder Head
C32 Engine for 777E Off-Highway Trucks Water Lines
Additional SMART Attachments Installation and Setup Information Is Now Available for Certain Work Tools {7620}
D7 Track-Type Tractor Electrohydraulic Systems Sensor Signal (Analog, Passive) - Test
Seat Suspension Group May Fail on Certain Track-Type Loaders {7324}