HOSE AS 2552757 - Caterpillar

electronic service tool and check for an active XXXX-3 diagnostic code for the suspect sensor.
Turn the keyswitch to the OFF position.
Reconnect the 40-pin connector.Results:
An XXXX-4 diagnostic code was active before disconnecting the 40-pin connector. An XXXX-3 diagnostic code became active after the 40-pin connector was disconnected - The fault is in the CEM harness.Repair: Repair the faulty wiring or replace the faulty wiring. Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.STOP
The XXXX-4 diagnostic code is still present - Leave the sensor disconnected. Proceed to Test Step 9.Test Step 9. Create an Open Circuit at the 31-Pin Connector
Turn the keyswitch to the OFF position.
Disconnect the 31-pin connector.
Turn the keyswitch to the ON position. Wait at least 30 seconds for activation of the diagnostic codes.Note: While the 31-pin connector is disconnected, diagnostic codes for the other components that are connected to the 31-pin connector will be active. Disregard the diagnostic codes for all the other components. Only address the 3485 and 2452 diagnostic codes.
Access the "Active Diagnostic Codes" screen on the electronic service tool and check for an active XXXX-3 diagnostic code for the suspect sensor.
Turn the keyswitch to the OFF position.
Reconnect the 31-pin connector.Results:
An XXXX-4 diagnostic code was active before disconnecting the 31-pin connector. An XXXX-3 diagnostic code became active after the 31-pin connector was disconnected. - The fault is in the harness between the 40-pin connector and the 31-pin connector.Repair: Repair the faulty wiring or replace the faulty wiring. Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault.STOP
The XXXX-4 diagnostic code is still present - Leave the sensor disconnected. Proceed to Test Step 13.Test Step 10. Create a Short Circuit at the Sensor Connector
Turn the keyswitch to the OFF position.
Disconnect the connector for the DPF inlet/ARD flame detection temperature sensor.
Fabricate a jumper wire that is 150 mm (6 inch) long.
For a 3485-3 diagnostic code, use the jumper to connect terminal 2 to terminal 3 on the sensor connector.For a 2452-3 diagnostic code, use the jumper to connect terminal 2 to terminal 4 on the sensor connector.
Turn the keyswitch to the ON position. Do not start the engine.
Access the "Active Diagnostic Codes" screen on the electronic service tool and check for an active XXXX-4 diagnostic code for the suspect sensor.
Remove the jumper. Reconnect the sensor.Results:
An XXXX-3 diagnostic code was active before installing the jumper. An XXXX-4 diagnostic code became active with the jumper installed. - There may be a fault in the sensor.Repair: Temporarily connect a new sensor to the harness, but do not install the new sensor in the DPF or the ARD. Use the electronic service tool in order to verify that the repair eliminates the fault and then permanently install the new sensor.Use the electronic service tool in order to clear all logged diagnostic codes.STOP
The XXXX-3 diagnostic code is still present - Proceed to Test Step 11.Test Step 11. Create a Short Circuit at the