SPRING 3967847 - Caterpillar

Illustration 1 g00850138
Typical air inlet shutoff solenoid
Table 3
Troubleshooting Test Steps    Values    Results    
7. Check the Supply Voltage to the Air Inlet Shutoff Solenoid
A. Connect Cat ET to the service tool connector.
B. Turn the key switch to the ON position.
C. Perform the "Air Inlet Shutoff Override" test in Cat ET.
D. Measure the voltage across the two terminals of the air inlet shutoff solenoid.
   
5 VDC    
Result:The voltage is within 5 VDC of battery voltage when the test is active. The ECM is properly controlling the relay for the air inlet shutoff solenoid, but the air inlet shutoff solenoid is not working.
Repair: Replace the air inlet shutoff solenoid. Verify that the repair eliminates the problem.
Result: The voltage is not within 5 VDC of battery voltage when the test is active. The air inlet shutoff solenoid is not receiving the correct signal.
Proceed to Test Step 8.
   
8. Check the Signal Voltage to the Relay
A. Connect Cat ET to the service tool connector.
B. Turn the key switch to the ON position.
C. Perform the "Air Inlet Shutoff Override" test in Cat ET.
D. Measure the voltage across the relay coil.
   
5 VDC    
Result: The voltage is within 5 VDC of battery voltage when the test is active.
The relay is receiving the signal from the ECM. Proceed to Test Step 9.
Result: The voltage is not within 5 VDC of battery voltage when the test is active.
The relay is not receiving the signal from the ECM. Proceed to Test Step 11.
   
9. Check the Power Supply to the Relay
A. Measure the voltage between the +Battery terminal of the relay and the engine ground.
   
5 VDC    
Result: The voltage is within 5 VDC of battery voltage. The relay is receiving power.
Proceed to Test Step 10.
Result: The voltage is not within 5 VDC of battery voltage. There is a problem in the wiring between the relay and the +Battery terminal.
Repair: Repair or replace the wiring harness. Verify that the repair eliminates the problem.
   
10. Check the Output Voltage of the Relay
A. Ensure that all of the circuits connectors are connected.
B. Turn the key switch to the ON position.
C. Perform the "Air Inlet Shutoff Override" test in Cat ET.
D. Measure the voltage from the output terminal on the relay to the engine ground.    
5 VDC    
Result: The voltage is within 5 VDC of battery voltage. There is a problem in the wiring between the relay and the air inlet shutoff solenoid.
Repair: Repair or replace the wiring harness. Verify that the repair eliminates the problem.
Result: The voltage is not within 5 VDC of battery voltage. The relay is not sending power to the air inlet shutoff solenoid.
Repair: Replace the relay for the air inlet shutoff. Verify that the repair eliminates the problem.
   
11. Check the Wiring for an Open Circuit
A. Turn the keyswitch to the OFF position for 2 minutes. The keyswitch must be off for two minutes to allow the DEF pump to purge, to reset the code, and to reset the