D6T XE Electrical & Hydraulic Troubleshooting Caterpillar

Power Transistor Drive and Feedback - Test

Usage:

D6 B72

The Power Inverter Control ECM controls 12 power transistors that are located inside the Power Inverter. These power transistors cannot be accessed inside the Power Inverter and are not serviceable.

The Power Inverter Control ECM continuously monitors the feedback signals from each of the power transistors via the Control Harness.

If the Power Inverter Control ECM is not receiving the correct feedback signal from any of the power transistors during machine operation, the ECM will disable operation of the power train.

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Illustration 1	g06092581
(J1) J1 Connector (J2) J2 Connector (A) Motor phase connection points (B) Generator phase connection points

Power Inverter Control ECM

The following is a list of Code Identifiers (CIDs) associated with the Power Transistors of the Power Inverter that are monitored by the ECM.

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Table 1
Power Inverter Control ECM
CID	Code Description	System Response
3430-14	Power Inverter Control Module: Special Instruction	Activated during machine operation or the Power Inverter Service Test. The Power Train will be disabled. Logs a Data Transport File

The following is a list of Event Identifiers (EIDs) associated with the Power Transistors of the Power Inverter that are monitored by the Power Inverter Control ECM.

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Table 2
Power Inverter Control ECM
EID	Code Description	System Response
2436	Drive Motor Phase A Power Positive #1 Signal Mismatch	Activated during machine operation or the Power Inverter Service Test. The Power Train will be disabled. The EID will be accompanied by a CID 3430-14. Logs a Data Transport File.
2438	Drive Motor Phase A Power Negative #2 Signal Mismatch
2440	Drive Motor Phase B Power Positive #1 Signal Mismatch
2442	Drive Motor Phase B Power Negative #2 Signal Mismatch
2456	Drive Motor Phase C Power Positive #1 Signal Mismatch
905	Drive Motor Phase C Power Negative #2 Signal Mismatch
2435	Generator Phase A Power Positive #1 Signal Mismatch	Activated during machine operation or the Power Inverter Service Test. The Power Train will be disabled. The EID will be accompanied by a CID 3430-14. Logs a Data Transport File.
2437	Generator Phase A Power Negative #2 Signal Mismatch
2439	Generator Phase B Power Positive #1 Signal Mismatch
2441	Generator Phase B Power Negative #2 Signal Mismatch
2457	Generator Phase C Power Positive #1 Signal Mismatch
928	Generator Phase C Power Negative #2 Signal Mismatch

These Power Inverter Control CIDs and EIDs are associated with the Power Inverter Control circuits that are under the control of the ECM. The Power Inverter Control ECM has detected a problem in one of the circuits between the Power Inverter Control ECM and the Power Inverter.

The conditions that can cause the Power Inverter Control ECM to activate the CID 3430 codes are:

An operational condition of the machine that exceeded an internal threshold of the Power Inverter.
A short or open circuit in the Control Harness, between the ECM and the Power Inverter, in the transistor signal or transistor feedback circuit.
An issue with the current sensor or voltage sensor circuitry between the ECM and the Power Inverter.
A malfunction of the current sensor or voltage sensor internal to the Power Inverter.
An issue with the temperature sensor internal to the Power Inverter.
Low system voltage at the Power Inverter.
A malfunction of the Power Inverter Control ECM.
A malfunction of the internal circuitry of the Power Inverter.

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Illustration 2	g06092741
Power Transistor connections

Diagnostic Trouble Code Procedure

This procedure should not require entry into any enclosures that contain hazardous voltage components and should not require any hazardous voltage connections to be disconnected. When an area that contains hazardous voltage components must be entered for a service procedure, the "Safe Shutdown Procedure for Electric Drive Tractors" procedure must be performed before any enclosures that contain hazardous voltage components are opened or before any hazardous voltage connectors are disconnected. Refer to the Troubleshooting, "Electrical Maintenance Guidelines" section of this manual. Perform the "Safe Shutdown Procedure for Electric Drive Tractors" procedure before any of the hazardous voltage areas are opened or before hazardous voltage connectors are disconnected.

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Table 3
FMI 14 Troubleshooting
Troubleshooting Test Steps	Values	Results
1. Collect Data Transport Files Additional engineering data is triggered by the following EIDs: 905, 928, 2435, 2436, 2437, 2438, 2439, 2440, 2441, 2442 A. Collect Data Transport files from the Power Inverter Control ECM. Refer to "Data - Transport" in this manual for instructions. B. Save the files on your computer for possible submission to Caterpillar.	Data Transport Files were successfully downloaded from the Power Inverter Control ECM and saved to your computer.	OK: Data Transport Files were successfully downloaded from the Power Inverter Control ECM and saved to your computer. Retain in the event a DSN ticket is submitted. Proceed to Test Step 2. NOT OK: Data Transport files were not successfully downloaded. Reattempt to collect Data Transport Files and then proceed to Test Step 2.
2. Check For Associated DTCs Involving The Power Inverter Control Phase Current Sensors	None of the following Power Inverter Control Phase Current Sensor DTCs are active: DTC 2792 DTC 2793 DTC 2794 DTC 2789 DTC 2790 DTC 2791	OK: No Power Inverter Control Phase Current Sensor DTCs are active. Proceed to Test Step 3. NOT OK: There are active Power Inverter Control Sensor DTCs. REPAIR: Resolve the problem causing these DTCs to activate. Refer to the Troubleshooting, "Current Sensor - Test." Proceed to Test Step 10.
3. Check For Associated DTCs Involving Power Inverter Control DC Power Bus Voltage Sensors	None of the following Power Inverter Control DC Power Bus Voltage Sensor DTCs are active: DTC 2934 DTC 2935	OK: No Power Inverter Control DC Power Bus Voltage Sensor DTCs are active. Proceed to Test Step 4. NOT OK: There are active Power Inverter Control DC Power Bus Voltage Sensor DTCs. REPAIR: Resolve the problem causing these DTCs to activate. Proceed to Troubleshooting, "Voltage Sensor - Test.". Proceed to Test Step 10.
4. Check For Associated DTCs Involving The Power Inverter Temperature Sensors	The following Power Inverter Temperature Sensor DTC is not active: DTC 2789	OK: No Power Inverter Temperature Sensor DTCs are active. Proceed to Test Step 5. NOT OK: There are active Power Inverter Sensor DTCs. REPAIR: Resolve the problem causing the DTC to activate. Proceed to Troubleshooting, "Sensor Signal (Analog, Passive) - Test (Power Inverter Temperature Sensor)". Proceed to Test Step 10.
5. Check For Associated EIDs Involving A Ground Fault	None of the following Ground Fault EIDs are active or recently logged: EID 715 EID 988	OK: No Ground Fault EIDs are active or recently logged. Proceed to Test Step 6. NOT OK: There are active or recently logged Ground Faults. REPAIR: Resolve the problem causing these DTCs to activate. Proceed to Troubleshooting, "Ground Fault- Test". After the Ground Fault is resolved, proceed to Test Step 10.
6. Check For Associated EIDs Involving The Power Inverter Control Phase Imbalance	EID 761 (Power Inverter Control Phase Imbalance) is not active or recently logged.	OK: No Power Inverter Control Phase Imbalance EIDs are active or recently logged. Proceed to Test Step 7. NOT OK: There are active or recently logged EIDs for Power Inverter Control Phase Imbalance. REPAIR: There are active or recently logged EIDs for Power Inverter Control Phase Imbalance. Proceed to Troubleshooting, "Event Codes" for EID 761. Proceed to Test Step 10.
7. Complete The Power Inverter Service Test By performing the service test, additional information and codes may be available that will help determine the specific problem. Record all results from the test.	The Power Inverter Service Test HAS been completed.	OK: The Power Inverter Service Test HAS been completed. Proceed to Test Step 8. NOT OK: The Power Inverter Service Test has not been completed. Proceed to Troubleshooting, "Power Inverter - Test" and complete the test. REPAIR: The Power Inverter Service Test will output an error to narrow down the potential causes of the DTC. Follow the Actions to Perform within Troubleshooting, "Power Inverter - Test" tables to further troubleshoot the DTC. The output of the Power Inverter Test may lead to the next step.
8. Check CatET For Other Active Or Recently Logged Codes	No other active or recently logged codes are present.	OK: No other active or recently logged codes are present. Proceed to Test Step 9. NOT OK: The Power Inverter Service Test created active or recently logged codes. REPAIR: Proceed to Troubleshooting, "Event Codes" to troubleshoot the active or recently logged codes. The results may lead to the next step.
9. Inspect Control Harness A. Turn the key switch and disconnect switch OFF. B. Ensure that the connectors have not been cross threaded and are properly installed. C. Check for brass shavings in the connector that may have been created by cross threading. The shavings can short pins together. D. Inspect and clean all the contacts of the harness connectors. Ensure that all the wires and sockets are secured in the connector. Ensure that the contacts are clean, dry, and in good condition. Ensure none of the pins at the ECM and Power Inverter are bent.	The Control Harness is free of damage, dirt, corrosion, and moisture. Each of the resistance measurements between the sensor contact and all the other contacts used in the harness is greater than 5 KΩ	OK: The Control Harness is free of damage, dirt, corrosion, and moisture. Each of the resistance measurements is greater than 5 KΩ. The resistance measurements indicate that the transistor circuit is not shorted to another circuit in the Control Harness. Proceed to Test Step 10. NOT OK: There is a contamination problem with the Control Harness. Or, at least one of the resistance measurements is less than 5 KΩ, indicating a short in the Control Harness. REPAIR: Clean all moisture, dirt, and corrosion from the harness. If the harness is damaged or has a short, replacement is necessary. The Control Harness is not serviceable. After the harness issue is fixed, repeat the Troubleshooting, "Power Inverter - Test" to ensure that the problem has been corrected.
10. Check If The Diagnostic Code Remains A. Reconnect all harness connectors. Return machine to normal operating condition. B. Turn the key switch and the disconnect switch ON. C. Clear all DTCs. D. Operate the machine. E. Stop the machine and engage the parking brake. F. Check if the DTC is active.	The DTC is no longer present.	OK: The DTC does not exist at this time. The initial DTC may have been caused by poor electrical connection or short at one of the harness connections. Resume machine operation. Proceed to Test Step 12. NOT OK: The DTC has not been corrected. If the DTC has not been corrected after performing the previous steps a second time, the ECM may need flashed with the latest software. Refer to Test Step 11.
11. Flash The Latest Software To The ECM The software program for the ECM causing this problem is unlikely. However, flash the latest version of ECM software to the ECM to eliminate this condition as a possible cause. A. To flash the latest software to the ECM, refer to Troubleshooting, "ECM Software - Install". B. Operate the machine. C. Stop the machine and engage the parking brake. D. Check if the DTC is active.	The DTC is no longer present. No new DTCs or EIDs have been activated.	OK: The DTC is no longer present. No new DTCs or EIDs have been activated. REPAIR: The latest software version flashed to the ECM has corrected the problem. Resume normal machine operation. NOT OK: The DTC has been activated again by the ECM. The new software program has not corrected the problem. Refer to Test Step 12.
12. Check The ECM Operation A. Obtain a spare ECM that can be substituted for the suspected ECM. The part number of the spare ECM must be the same part number as the suspected ECM. B. To replace the suspected ECM with another ECM that has the latest ECM software installed, refer to "ECM - Replace" in this manual. After completing the ECM replacement procedure, return to this procedure and proceed to the next step. C. After the spare ECM has been installed in place of the suspected ECM and the latest version of ECM software has been flashed, turn the key switch to the OFF position. D. Start the engine. Run the engine at low idle. E. Determine if the DTC is active.	The DTC is not active. No new DTCs or EIDs have been activated.	OK: The DTC is no longer active and no new DTCs or EIDs have been activated. REPAIR: The spare ECM that has been installed in place of the original ECM is operating correctly and no new problems have been detected. The ECM that was replaced appears to have been the cause of the problem. Return the ECM to your parts department for return to Caterpillar for evaluation. Resume normal machine operation. STOP. NOT OK: The DTC has been activated by the replacement ECM. The problem has not been corrected. REPAIR: The activation of the original DTC indicates that the original ECM was not causing the problem. Repeat this Check The ECM Operation test step and install the original ECM back in place of the spare ECM that was installed. If the DTC remains active or if the DTC is repeatedly activated and no cause can be found, contact the dealership Technical Communicator to consult with the Cat dealer Solutions Network (DSN). Indicate the steps that have been taken to try to find the cause of this problem. The DSN will contact qualified company personnel that can further recommend action to take to determine the cause of the problem. STOP.