The following is a list of Diagnostic Trouble Codes (DTCs) that are associated with the battery cable shields of the machine.
| Transmission ECM (MID 27) | ||
| DTC | Code Description | System Response |
| 3035-3 | Battery Cable Shield : Voltage Above Normal | A Warning Level 3 Will Be Generated. |
| 3035-4 | Battery Cable Shield : Voltage Below Normal | A Warning Level 3 Will Be Generated. |
About Battery Cable Shield Monitoring
Battery Cable Shield Monitoring is utilized on medium wheel loaders that have electrohydraulic (EH) steering. A battery cable shorted to ground can shut down an ECM. However, using a shielded battery cable system allows the system to detect battery cable insulation damage before power to the ECM is compromised. There are two circuits that run in parallel for battery cable shield monitoring:
- Coaxial Mesh
- Spiral Wire
The coaxial mesh is on the outside of the cable and will detect rubbing/chafing before the battery cable is damaged. When the coaxial mesh is damaged, a diagnostic trouble code will be activated by the Implement ECM.
The spiral wire around the battery cable is connected to the resistors in the circuit. This cable provides a good connection point for the resistors. The spiral wire is in direct contact with the mesh all around the battery cable. If there is damage to the mesh on one side, the spiral wire will identify the damage. The spiral wire is wrapped entirely around the cable. This damage could be the result of chaffing over a long period. The damage could also be the result of a nick in the shielding of the harness due to an impact. Diagnostics on the battery cable shield voltage will be inhibited in the following situations:
- Startup
- Shut down
- Engine Cranking
- Low system voltage diagnostics
- High system voltage diagnostics
Diagnostic Trouble Code (DTC) Root Causes
Possible causes for a 3035-3 DTC
ECM detects voltage above normal on the battery cable shield circuit, due to:
- The signal circuit has shorted to +battery.
- The signal wire is open.
- A resister has an open.
- The ECM has failed. A failure of the ECM is unlikely.
Possible causes for a 3035-4 DTC
The ECM detects voltage below normal on the battery cable shield circuit, due to:
- A short circuit between the shield and frame ground.
- The Implement ECM has failed. (ECM failure is unlikely.)
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| Illustration 1 | g03744600 |
|
Battery Cable Shield Monitor Circuit Schematic | |
Note: The diagram above is a simplified schematic of the Battery Cable Shield circuit. Refer to the latest revision of the Machine Electrical Schematic for complete circuit information, including harness connectors.
Diagnostic Trouble Code (DTC) Procedure
| Battery Cable Monitoring System | ||
| Connected Resisters | System Resistance to Ground | System Voltage |
| None | NA | 5.0 ± 0.1 VDC |
| 1 | 1500 ohms | 3.75 ± 0.1 VDC |
| 2 | 750 ohms | 3.0 ± 0.1 VDC |
| 3 (1) | 500 ohms | 2.5 ± 0.1 VDC |
| (1) | System resister #3 is only installed with the secondary steer attachment. |
Note: Two system resisters is the standard arrangement. A system resister #4 is used only in the battery cables for the optional cold weather (four batteries) attachment. This resistor cannot be used with the standard battery cables. Therefore, values for system resistance and voltage should be for two resisters (or for three resistors, if secondary steering is available).
Note: Poor connections can often be the cause of a problem in an electrical circuit. Prior to beginning this procedure, inspect the harness connectors that are involved in this circuit. Verify that the involved connections in the circuit are clean, secure, and in good condition. Check the wiring for pinch points or abrasions. Look for and repair areas that indicate wires are exposed. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing a troubleshooting procedure. Refer to Testing and Adjusting, "Electrical Connector - Inspect " section of this manual.
| Troubleshooting Test Steps | Values | Results |
|---|---|---|
| 1. Identify The Active Diagnostic Trouble Code (DTC) | DTC present | 3035-3 DTC, proceed to Test Step 2. 3035-4 DTC, proceed to Test Step 6. |
| Begin 3035-3 DTC Troubleshooting HERE | ||
| 2. Check The ECM Voltage Supply A. Turn the disconnect switch to the OFF position. B. Find and disconnect the shield resistor legs from the system until no resistors are connected to the ECM supply wire P835-GY(Grey). Turn keyswitch to ON position. Check the voltage between the ECM circuit and frame ground. |
The ECM circuit supply voltage is approximately 5.0 VDC |
OK - Voltage is 5.0 VDC. Proceed to Test Step 4. NOT OK - The voltage is not approximately 5.0 VDC. Proceed to Test Step 3. |
| 3. Check The ECM Voltage Supply At The ECM Pin Note: The shield resistor legs remain disconnected. A. Remove the P835-GY from the ECM harness connector with a wire removal tool. B. Turn Key start Switch to the ON position, insert the "spoon" type multimeter probe through the hole where the P835-GY wire was removed. Contact and measure the voltage at the ECM pin. |
The voltage is approximately 5 VDC. |
OK - Voltage is approximately 5 VDC. Proceed to Test Step 4. NOT OK - The voltage is not approximately 5 VDC. Repair: Ensure that you have the latest version of software for your specific ECM. Refer to Testing and Adjusting, "Electronic Control Module (ECM) - Flash Program" in this manual. If the voltage at the ECM pin is not approximately 5.0 VDC, the ECM may have failed. Prior to replacing an ECM, contact your dealer Technical Communicator (TC) for possible consultation with Caterpillar. This consultation may greatly reduce repair time and expense. If the ECM must be replaced, refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace" Proceed to Test Step 8. |
| 4. Check For A Short To Battery A. Turn the disconnect switch and the key start switch to the OFF position. B. At each resister leg that is disconnected, measure the resistance between the battery cable and the shield wire. |
Each resistance measurement between each leg and the shield wire is greater than 5000 ohms. |
OK - Each resistance measurement is greater than 5000 ohms. None of the resistance measurements are indicating a short to the battery cable. Proceed to Test Step 5. NOT OK - There is a short indicated between one of the battery cables and the corresponding shield. Proceed to Test Step 8. |
| 5. Check For An Open A. Turn the disconnect switch and the key start switch to the ON position. B. One at a time, connect one of the shield resister legs to the system. Check the system voltage when each resister leg is connected as compared to the voltage in Table 2. Repeat the steps until the resister leg is found where the voltage is not correct according to Table 2. An incorrect voltage measurement indicates the leg that contains the problem. |
The circuit voltage is comparable to Table 2 when each leg is connected. |
OK - When each leg is connected to the system, the voltage is close to what is listed in Table 2. Proceed to Test Step 8. NOT OK - When one of the legs is connected, the voltage does not compare to the voltage listed in Table 2. Verify that the resistance of the resistor is correct. Repair: Replace the resistor or the battery cable that has the shield that is causing the problem. Proceed to Test Step 8. |
| Begin 3035-4 DTC Troubleshooting HERE | ||
| 6. Check For A Short To Frame Ground A. Turn the disconnect switch and the key start switch to the OFF position. B. For each resister leg, check resistance between the shield wire and frame ground. |
The resistance is greater than 5000 ohms. |
OK - The resistance is greater than 5000 ohms. Proceed to Test Step 7. NOT OK - One or more resistance measurements are less than 5000 ohms. Repair: Repair or replace the cable with the low resistance Proceed to Test Step 8. |
| 7. Check The Voltage Between The ECM Circuit And Frame Ground A. At the ECM connector J1-30, remove the circuit wire from the harness connector. B. Turn the disconnect switch and the key start switch to the ONposition. C. With the multimeter probes, contact the ECM pin. Measure voltage between the contact J1-30 and a clean ground connection on the machine chassis. |
The voltage is approximately 5 VDC. |
OK - The voltage is approximately 5 VDC. Contact your Technical Communicator (TC) and indicate the tests that have been performed and the results that have been observed. Proceed to Test Step 8. NOT OK - The ECM has failed. ECM failure is unlikely. Repair: Verify that all possible causes of the diagnostic code have been investigated. If the diagnostic code remains active or is repeatedly activated and no cause can be found, flash the ECM with the latest version of software. Ensure that you have the latest version of software for your specific ECM. Refer to the Testing and Adjusting, "Electronic Control Module (ECM) - Flash Program" in this manual. If all possible causes of the problem have been investigated and no problem can be found, the ECM may have failed. Before replacing an ECM, contact your dealer TC for possible consultation with Caterpillar. This consultation may greatly reduce repair time and expense. If the ECM must be replaced, refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace" in this manual. Proceed to Test Step 8. |
| 8. Check If The Diagnostic Trouble Code (DTC) Remains A. Inspect the contacts of the harness connectors and clean the contacts. (1) B. Reconnect all harness connectors. C. Turn the disconnect switch and the key start switch to the ON position. D. Operate the machine. E. Check if the 3035 DTC is active. |
Diagnostic code is no longer present. |
OK - The DTC is no longer active. Repair: The initial DTC could have been caused by a poor electrical connection or a short at one of the harness connectors. Resume normal machine operation. STOP NOT OK - The DTC is active. Repair: A failure of the Machine ECM is unlikely. If the cause of the diagnostic code is not found, the ECM may have failed. Prior to replacing an ECM, contact your Technical Communicator (TC) for possible consultation with Caterpillar. This consultation may effect repair time. If the ECM requires replacement, refer to Troubleshooting, "ECM - Replace" in this manual. STOP |
| (1) | Refer to Testing and Adjusting, "Electrical Connector - Inspect " section of this manual. |