TANK GP-FUEL 5257638 - Caterpillar

from the engine.
Connect the suspect sensor to the sensor connector.
Connect the vacuum pump test unit to the suspect sensor.
Connect the vacuum pump to the differential pressure gauge.
Turn the ECS to the ON position. The engine should be OFF.
Observe the pressure reading for the suspect sensor. The ET should display the barometric pressure in your area.
Use the vacuum pump to pull 5 kPa (0.7 psi) of vacuum on the differential pressure gauge.Note: The pressure gauge reading should remain constant until the vacuum is released.
Compare the readings on the ET and the pressure test kit.Expected Result:The ET should show constant pressure. The ET should show a 5 2 kPa (0.7 0.3 psi) drop in pressure.Results:
OK - The sensor is working correctly. Reset the system and note any active diagnostic codes. Stop.
Not OK - Proceed to test step 14.
Vacuum Leak - Repair: Check for leaks. If no leaks are found there is an internal leak in the suspect pressure sensor. Replace the sensor and calibrate the sensor. Reset the system and note any active diagnostic codes. Stop.Test Step 12. Install a Jumper Wire.
Connect the suspect sensor.
Remove the suspect sensor signal wire from the ECM. Remove the suspect ground wire from the ECM.
Use a wire with socket terminals at each end. Connect the jumper wire at the ECM between the sensor signal and the ground.
Turn the ECS to the ON position. The engine should be OFF.
The CID-FMI should change from 03 to 04 when the jumper is in place.Expected Result:The diagnostic code should change from a FMI of 03 to an FMI of 04.Results:
OK - There is a problem with the wiring between the ECM and the suspect sensor.Repair: Repair the connectors and/or wiring or replace the connectors and/or wiring. Stop.
Not OK - Replace the ECM.Repair: Refer to Troubleshooting, "Replacing the ECM". Stop.Test Step 13. Create an Open at the ECM.
Turn the ECS to the OFF/RESET position.
Disconnect the suspect sensor signal wire from the ECM connector.
Turn the ECS to the ON position. The engine should be OFF.
Check if the CID-FMI has changed from 04 to 03.Note: Disconnecting the Atmospheric Pressure Sensor will cause several sensor diagnostic codes to become active. Troubleshoot the original code. Reset the system. Delete the logged diagnostic codes when you are finished.Expected Result:The CID-FMI should change from 04 to 03 when the sensor signal wire is disconnected.Results:
OK - The diagnostic code has changed from a FMI of 04 to an FMI of 03.Repair: Repair the connectors and/or wiring or replace the connectors and/or wiring. Stop.
Not OK - Replace the ECM.Repair: Refer to Troubleshooting, "Replacing the ECM". Stop.Test Step 14. Check the Voltage at the Sensor Connector.
Turn the ECS to the OFF/RESET position.
Measure the analog sensor voltage. Turn the ECS to the ON position. The engine should be OFF.
Measure the voltage between pin