CORE AS-HYDRAULIC OIL COOLER 2508327 - Caterpillar

Table 1
Troubleshooting Test Steps    Values    Results    
1. Check The ECM For Power And Ground
At the ECM, measure the voltage from contact 1 to contact 2.     The voltage is system voltage.     OK - The voltage is system voltage. The power supply circuit to the ECM is correct.
STOP.
NOT OK-The voltage is not system voltage
Proceed to Test Step 2.    
2. Check The Fuse
Whenever the machine electronic components fail to function, check the appropriate fuse for the ECM.
A. Check the fuse for the ECM.    
The fuse is correct.     OK - The fuse is correct.
Proceed to Test Step 3.
NOT OK-The fuse is not correct.
Repair: Replace the blown fuse or reset the circuit breaker. Observe the machine for a recurrence of the problem. If the problem persists, the reason for the blown fuse must be isolated and corrected.
STOP.    
3. Check The Power Wire To The ECM
A. Turn the key start switch and the disconnect switch to the OFF position.
B. At the fuse, connect the lead from the multimeter to wire 133-RD.
C. At the ECM, connect the other lead from the multimeter to connector contact 1 and measure the resistance.    
The resistance is less than 5 ohms.     OK - The resistance is less than 5 ohms. The wiring circuit is correct.
Proceed to Test Step 4.
NOT OK-The resistance measurement is greater than 5000 ohms. The wiring has an open circuit.
Repair: Repair the wiring harness or replace the wiring harness.
STOP.    
4. Check The ECM Ground Connections
A. The keyswitch and the disconnect switch remain in the OFF position.
B. At the ECM, measure the resistance from connector contact 2 to frame ground.    
The resistance is less than 5 ohms.     OK -The resistance is less than 5 ohms. The ground circuit is correct. The ECM may have failed. This is unlikely. Perform this entire procedure again. If the problem remains, the ECM may need to be replaced. Contact your dealerships for possible consultation with Caterpillar. This consultation may greatly reduce repair time.
STOP.
NOT OK -The resistance is greater than 5000 ohms. The ground circuit has failed.
STOP.