VALVE-AIR 5N2178 - Caterpillar

Illustration 1 g01320751
Connector locations for the temperature control module
(1) 8-pin connector for the motor assembly and the communications device
(2) 12-pin connector for the engine harness
Illustration 2 g02554619
Removing the inspection cover from the motor assembly
(3) Main shaft extension
(4) Plug and O-ring seal
Illustration 3 g01321224
Table 3
Troubleshooting Test Steps Values Results
7. Temperature Control Module
A. Perform the following procedure:
1. Visually inspect the wiring from the TCM to the coolant temperature sensor and from the temperature control module to the power supply. Visually inspect the 12-pin connector and the 8-pin connector at the temperature control module. Check for a tight connection at the connectors.
B. Check for proper operation of the electronic fluid temperature control:
1. Ensure that the keyswitch is in the OFF position. Turn the electrical disconnect to the OFF position.
2. Remove cover bolts (4) from the motor assembly. Remove the inspection cover from the motor.
3. Use the appropriate wrench to rotate the main shaft extension. Ensure that the shaft rotates freely. Rotate the shaft to ensure that the piston is not positioned at one of the ends stops of the valve.
4. Visually inspect main shaft extension (3) for rotation while you establish power to the ECM and to the keyswitch circuit. The shaft will rotate several times during the powerup sequence.
5. During the power-up sequence, listen for the valve to travel to the end stop. Listen for the piston to hammer the end stop to establish the valve position.
6. With the electrical disconnect in the ON position, disconnect the engine harness connector (12-pin connector) at the controller. Diagnostic codes related to the valve will be activated.
7. Use a wrench to rotate the main shaft extension to position the valve piston away from the end stop of the valve.
8. Connect the connector and observe the motor assembly. The valve will repeat the power-up sequence when the engine harness (power) is connected. While you connect the connector, check the main shaft extension for rotation. The valve will hammer at the end stop.
9. Turn the electrical disconnect to the OFF position. Replace the inspection cover and connect all connectors.
C. Disconnect the engine harness connector (12 pin) at the temperature control module.
D. Measure the voltage between terminal 1 (voltage supply) and terminal 5 (return) on the harness side of the 12-pin connector at the TCM. The supply voltage for the control module must be between 18 V and 32 V.
E. Restore the wiring to the original configuration.
The Connectors and Wiring, Operation of TCM, and 18 V - 32 V
Result: The Connectors and Wiring are OK.
Continue with this step.
Result: The Connectors and Wiring are NOT OK.
Repair: Repair or replace as necessary.
Continue with this step.
Result: The TCM is OK.
Continue with this step.
Result: The TCM is NOT OK.
Repair: If the piston binds during travel, disassemble and inspect the motor mount to determine the cause of the binding. Do not apply excessive force to the main shaft extension. Extensive damage to the shaft bearings may occur. Refer to Disassembly and Assembly, "Thermostatic Valve - Disassemble" for disassembly instructions.
Note: The TCM may be operated