TUBE 6L8881 - Caterpillar

Illustration 10 g01641533
Terminal locations for the electronic fluid temperature control at the harness connector for the TCM
(Terminal 1) +Battery
(Terminal 3) Return
(Terminal 5) −Battery
(Terminal 8) Keyswitch
(Terminal 10) Sensor signal
Illustration 11 g01765294
Terminal locations at the machine interface connector for the temperature sensor at the outlet of the coolant pump
(Terminal 28) Sensor signal
(Terminal 34) Return
Illustration 12 g01241538
Terminal locations at the temperature sensor at the outlet of the coolant pump
(Terminal 1) Sensor signal
(Terminal 2) Return
Table 2
Troubleshooting Test Steps Values Results
1. Check for an Active Diagnostic Code
A. Connect Cat ET to the service tool connector.
B. Restore the electrical power to the ECM.
C. Monitor the diagnostic codes on Cat ET. Check and record any diagnostic codes.
Note: Wait at least 30 seconds in order for the diagnostic codes to become active.
D. Determine if a diagnostic code has occurred several times.
Note: A diagnostic code that is logged several times is an indication of an intermittent problem. Most intermittent problems are the result of a bad connection between a socket and pin in the connector. An intermittent problem may also be caused by a poor connection between a wire and terminal.
E. Look for the following diagnostic codes that are active or logged:
- 168-3
- 168-4
- 2349-19
- 2854-9
- 4193-2
- 4193-3
- 4193-4
F. Remove the electrical power from the ECM.
Active Diagnostic Code
Result: No diagnostic codes are active.
Repair: There may be an intermittent problem in the harness or in a connector. If an intermittent problem is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct procedures for inspecting electrical connectors.
Result: A 168-3 or 168-4 diagnostic code is active.
The TCM has detected a problem with the supply voltage to the unit.
Proceed to Test Step 2.
Result: The 2854-9 diagnostic code is active.
The ECM detects a problem with data link communications for the TCM.
Proceed to Test Step 2.
Result: The 2349-19 diagnostic code is active.
The ECM is reporting that the TCM detects a problem in the circuit for the temperature sensor at the coolant pump.
Proceed to Test Step 4.
Result: A 4193-2, 4193-3, or 4193-4 code is active.
The TCM detects a problem in the circuit for the temperature sensor at the coolant pump.
Proceed to Test Step 4.
2. Check the Supply Voltage at the TCM
A. Disconnect the harness connector at the TCM.
B. Restore the electrical power to the ECM. Ensure that the keyswitch is in the ON position.
C. Use a multimeter to measure the supply voltage between terminal 1 (+Battery) and terminal 5 (−Battery) on the harness side of the connector.
D. Remove electrical power from the ECM.
18 V and 32 V
Result: The supply voltage is between 18 V and 32 V.
Proceed to Test Step 3.
Result: The supply voltage is not between 18 V and 32 V.
Check the condition of the 15 Amp fuse that is in the fuse panel in the cab of the machine.
3. Check for Keyswitch Power at the TCM
A. Ensure that the harness connector for the TCM has been disconnected.
B. Restore the electrical power to the ECM. Ensure that the disconnect switch is in the ON position.
C. Use a multimeter to measure the keyswitch power between