C175-16 Locomotive Engine Caterpillar

Use this procedure to troubleshoot the electrical system if a problem is suspected with the Temperature Control Module (TCM). Also, use this procedure if one of the diagnostic codes in Table 1 is active.

Table 1

J1939 Code and Description	CDL Code and Description	Comments
4193–9 Engine Coolant Pump Outlet Temperature : Abnormal Update Rate	2854–9 Coolant Temperature Control Module : Abnormal Update Rate	The TCM cannot communicate with the engine ECM.
4193–14 Engine Coolant Pump Outlet Temperature : Special Instruction	2854–14 Coolant Temperature Control Module : Special Instruction	At startup, the ECM detected a mismatch between the engine software and the Temperature Control Module (TCM) hardware.
4193-19 Engine Coolant Pump Outlet Temperature : Data Error	2349-19 Engine Coolant Pump Outlet Temperature Sensor : Data Error	The coolant temperature control module reported that there is a problem with the circuit for the coolant temperature sensor. The problem is communicated to Electronic Control Module (ECM) via the CAN data link.

Illustration 1	g06081821

Table 2

Troubleshooting Test Steps	Values	Results
1. Check for Codes A. Connect Cat® Electronic Technician (ET) to the service tool connector. B. Look for active codes that are associated with the system for the event code.	Codes	Result: A -9 code is present. Proceed to Test Step 8. Result: A -14 code is present. Proceed to Test Step 5.
2. Check for Opens in the Engine Coolant Pump Outlet Temperature Sensor Wiring Harness A. Turn the keyswitch to the "OFF" position. B. Disconnect the Engine Coolant Pump Outlet Temperature Sensor wiring harness from the sensor. C. Disconnect the wiring harness connector from the Coolant Temperature Control Module. D. Measure the resistance between terminal 10 (SIGNAL) on the Coolant Temperature Control Module connector and terminal 1 (SIGNAL) on the Coolant Pump Outlet Temperature Sensor Connector. E. Measure the resistance between terminal 3 (RETURN) on the Coolant Temperature Control Module connector and terminal 2 (RETURN) on the Coolant Pump Outlet Temperature Sensor connector.	Open Circuit	Result: There were less than 10 Ohms of resistance between the Engine Coolant Pump Outlet Temperature Sensor circuit wires. Proceed to Test Step 3. Result: There were more than 10 Ohms of resistance on any one of the Engine Coolant Pump Outlet Temperatures Sensor circuit wires. Repair: There is an open in the wiring harness. Repair the wiring or replace the harness. Verify that the problem is resolved. Proceed to Test Step 10.
3. Check for Short Circuits in the Engine Coolant Pump Outlet Temperature Sensor Wiring Harness A. Turn the keyswitch to the "OFF" position. B. Disconnect the Engine Coolant Pump Outlet Temperature Sensor wiring harness from the sensor. C. Disconnect the wiring harness connector from the Coolant Temperature Control Module. D. Measure the resistance between terminal 10 (SIGNAL) on the Coolant Temperature Control Module connector and a good chassis ground. E. Measure the resistance between terminal 3 (RETURN) on the Coolant Temperature Control Module connector and a good known good chassis ground.	Short Circuit	Result: There were more than 100 K Ohms of resistance between the connector terminal and ground on both of the Engine Coolant Pump Outlet Temperature Sensor circuit wires. Proceed to Test Step 4. Result: There were less than 100 K Ohms of resistance between the connector terminal and ground on any one of the Engine Coolant Pump Outlet Temperatures Sensor circuit wires. Repair: There is a short circuit to ground in the wiring harness. Verify that the problem is resolved Proceed to Test Step 10.
4. Check for Short Circuits in the Engine Coolant Pump Outlet Temperature Sensor Wiring Harness A. Turn the keyswitch to the "OFF" position. B. Disconnect the Engine Coolant Pump Outlet Temperature Sensor wiring harness from the sensor. C. Disconnect the wiring harness connector from the Coolant Temperature Control Module. D. Measure the resistance between terminal 10 (SIGNAL) on the Coolant Temperature Control Module connector and all other pins in the Coolant Temperature Control Module connector. E. Measure the resistance between terminal 3 (RETURN) on the Coolant Temperature Control Module connector and all other pins in the Coolant Temperature Control Module connector.	Short Circuit	Result: There were more than 100 K Ohms of resistance between all the Engine Coolant Pump Outlet Temperature Sensor circuit wires. Repair: A failed Engine Coolant Pump Outlet Temperature Sensor has been detected. Replace the Engine Coolant Pump Outlet Temperature Sensor. Proceed to Test Step 10. Result: There were less than 100 K Ohms of resistance between any of the Engine Coolant Pump Outlet Temperatures Sensor circuit wires. Repair: There is a pin to pin short circuit in the harness. Repair the wiring or replace the harness. Verify that the problem is resolved. Proceed to Test Step 10.
5. Check the Part Number of the Component A. Locate the part number for the component that was identified by the "System Communication Status". Check to see if the part number is correct for the application.	Part Number	Result: The part number is incorrect for the application. Repair: Replace the component with the correct part number. Proceed to Test Step 10. Result: The part number is correct for the application. Proceed to Test Step 6.
6. Check for Incorrect Configuration Parameters A. Connect to Cat ET. B. Use Cat ET to verify that the correct parameters are being used.	Parameters	Result: The parameters are correct. Proceed to Test Step 7. Result: The parameters are not correct. Repair: Input the correct parameters. Refer to Troubleshooting, Configuration Parameters for additional information. If the problem is not resolved, proceed to Test Step 7.
7. Ensure that the latest Flash File Software is Installed in the ECM A. Connect Cat ET. B. Use Cat ET to verify that the correct flash file is being used.	Flash File	Result: The latest flash file is installed. Proceed to Test Step 10. Result: The latest flash file is not installed. Repair: Perform the following procedure: 1: Download the latest flash file from SIS Web. 2: Install the software into the ECM. Refer to Troubleshooting, ECM Software - Install for additional information. Proceed to Test Step 10.
8. Check the Resistance of the Data Link A. Remove electrical power from the engine. B. Measure the resistance of the data link between the following terminals on the 12-pin TCM wiring harness connector: -Pin 4 (CAN +) and Pin 6 (CAN-)	60±10 Ohms	Result: The resistance is less than 50 Ohms. Repair: There are more than 2 terminating resistors installed in the wiring harness or a short circuit has been detected. Repair or replace damaged components. Proceed to Test Step 10. Result: The resistance is 120±10 Ohms. Repair: There is a problem with a terminating resistor. Check the resistance on each terminating resistor. Replace the failed terminating resistor. Proceed to Test Step 10. Result: The resistance is greater than 130 Ohms. Repair: There is a problem with both terminating resistors or an open circuit has been detected. Determine the cause of the problem. Repair or replace damaged components. Proceed to Test Step 10. Result: The resistance is 60±10 Ohms. The terminating resistors are OK. Proceed to Test Step 9.
9. Check the Power and the Ground to the TCM A. Turn the breaker to the ON position. B. Measure the voltage between the following TCM wiring harness connector terminals: -Pin 1 (Battery +) and Pin 5 (Battery -)	Voltage	Result: The voltage is not equal to battery voltage. Repair: There is an open or short in the wiring circuit. Repair or replace the wiring circuit. Refer to the machine-specific schematic for wiring information. Proceed to Test Step 10. Result: The voltage is equal to battery voltage. Repair: Replace the TCM. Proceed to Test Step 10.
10. Check for codes A. Turn the keyswitch to the "On" position. B. Observe the "Active Diagnostic" screen on Cat ET. Wait at least 30 seconds for codes that may become active.	Diagnostic Codes	Result: The code did not return. Return the unit to service.

If the procedure did not correct the issue, contact your Cat Dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).