844K Wheel Dozer Caterpillar


ECM Location Code - Test

Usage:

844K K4Y

Transmission ECM

This test is associated with identifying the harness connection with a specific electronic control module. The control module is generally seeking a grounded or powered condition at specific pin locations on the wiring harness to confirm that the ECM is a match for the wiring harness.

The following is a list of codes associated with the ECM location code for the Transmission ECM.

Table 1
Transmission ECM (MID 81) 
DTC   Code Description  System Response 
1326-2  ECM Location Code: Data erratic, intermittent, or incorrect  The transmission control may be unable to communicate with other modules. 

The ECM location code is defined by wires going from the ECM location code pins on the ECM to ground. The combination of wires connected to ground corresponds with the software on the ECM. If the incorrect wires are connected to ground, or the incorrect version of the ECM software is installed a 1326-2 diagnostic code will occur.

Possible Causes for a DTC 1326-2 Diagnostic Trouble Code Are:

  • The wires for the location code are open or the wires are shorted.

  • The wrong software is installed on an ECM.


Illustration 1g03674381
Location Code Pin Graphic for Transmission ECM.

Note: The diagram above is a simplified schematic of the Transmission ECM connections. The schematic is electrically correct. However, not all of the possible harness connectors are shown. Refer to the latest revision of: Electrical Schematic , UENR4996, "844K Wheel Dozer (T4F) Electrical System Schematic". Electrical Schematic , UENR1697, "844K Wheel Dozer (LRC) Electrical System Schematic".

Implement ECM

This test is associated with identifying the harness connection with a specific electronic control module. The control module is generally seeking a grounded or powered condition at specific pin locations on the wiring harness to confirm that the ECM is a match for the wiring harness.

The following is a list of codes associated with the ECM location code for the Implement ECM.

Table 2
Implement ECM (MID 82) 
DTC   Code Description  System Response 
1326-2  ECM Location Code: Data erratic, intermittent, or incorrect  If the location code is incorrect the implement application will not run.
All solenoids will be OFF. 

The ECM location code is defined by wires going from the ECM location code pins on the ECM to ground. The combination of wires connected to ground corresponds with the software on the ECM. If the incorrect wires are connected to ground, or the incorrect version of the ECM software is installed a 1326-2 diagnostic code will occur.

Possible Causes for a DTC 1326-2 Diagnostic Trouble Code Are:

  • The wires for the location code are open or the wires are shorted.

  • The wrong software is installed on an ECM.


Illustration 2g03674382
Location Code Pin Graphic for Implement ECM.

Note: The diagram above is a simplified schematic of the Implement ECM connections. The schematic is electrically correct. However, not all of the possible harness connectors are shown. Refer to the latest revision of: Electrical Schematic , UENR4996, "844K Wheel Dozer (T4F) Electrical System Schematic". Electrical Schematic , UENR1697, "844K Wheel Dozer (LRC) Electrical System Schematic"

Diagnostic Trouble Code Procedure

Note: 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 2 diagnostic code, proceed to Table 3.

Table 3
FMI 2 Troubleshooting 
Troubleshooting Test Steps  Values  Results 
1. Verify Hardware And Software Part Numbers

A. Verify that the part numbers for the ECM are correct.

Note: Consult your Dealer for the correct part numbers. 

All part numbers are correct. 
OK - All part numbers are correct.

Proceed to Test Step 2.

NOT OK - All part numbers are NOT correct. The installed ECM has the wrong part number or incorrect configuration software.

Proceed to Test Step 6. 
2. The Location Code Should Match The Summary Screen

A. Check the Cat® Electronic Technician (Cat ET) Service Tool summary screen for the location code.
 

The location codes in Cat ET are correct. 
OK - The location codes in Cat ET are correct.

Proceed to Test Step 3.

NOT OK - The location code is NOT correct.

Repair: Verify that the software and hardware part numbers are correct. If the numbers are not correct, exit this procedure and correct the problem.

Proceed to Test Step 6. 
3. Inspect The Harness Connections

A. Turn the key start switch and the disconnect switch to the OFF position.

B. Inspect the harness connections that are related to the location code. Make sure that the connectors are clean and tight.

C. Verify that all connections in the circuit are clean, secure, and in good condition. 

The machine harness connections are tight and free of corrosion. 
OK - The machine harness connectors are tight and free from corrosion. All part numbers are correct.

Proceed to Test Step 4.

NOT OK - The machine harness connectors are in the need of repair.

Repair: Repair or replace the machine harness.

Proceed to Test Step 6. 
4. Check The Harness For A Short

A. The disconnect switch and the key start switch remain in the OFF position.

B. Disconnect the machine harness from the ECM.

C. At the ECM harness connector, measure the resistance between the location code contacts and all of the other contacts that are used for the ECM.

Note: Refer to the table above for the ECM location code connections. 

Each resistance is greater than 5K Ω. 
OK - The resistance is greater than 5K Ω. The harness circuit is correct.

Proceed To Test Step 5.

NOT OK - One or more readings less than 5 Ω. The short is between the location code and the circuit with the low resistance.

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 Test Step 6. 
5. Check The Harness For An Open

A. The disconnect switch and the key start switch remain in the OFF position.

B. The ECM harness connectors remain disconnected.

C. At the machine harness for the ECM, measure the resistance between the location code contacts and frame ground.

Note: Refer to the table above for the ECM location code connections. 

Each resistance is less than 5 Ω. 
OK - The resistance is less than 5 Ω. The harness circuit is correct.

Proceed To Test Step 6.

NOT OK - One or more readings greater than 5 Ω. The machine harness has failed.

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 Test Step 6. 
6. Check If The Diagnostic Code Remains

A. Reconnect all harness connectors. Return machine to normal operating condition.

B. Turn the key start switch and the disconnect switch ON.

C. Clear all diagnostic codes.

D. Operate the machine.

E. Stop the machine and engage the safety lock lever.

F. Check if the diagnostic code is active. 

The diagnostic code is no longer present. 
OK - The diagnostic code does not exist at this time. The initial diagnostic code may have been caused by poor electrical connection or short at one of the harness connections. Resume machine operation.

STOP.

NOT OK - 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 Caterpillar. This consultation may effect repair time.

Follow the steps in Troubleshooting, "ECM - Replace" if the ECM needs to be replaced.

STOP. 

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