Is it possible the air filter or intake pipes have become plugged with snow? Event code is for low intake air pressure. Also check for a hose blown or burst from the intake back to the turbocharger.
Below are the details for each code. The event code should be checked first. If the other codes are active, they will have an * or the letter A with the code. If they do, the dealer will need to check the engine electronics. If not, they are old codes and you do not need to worry about them.
1785-21 Intake Manifold Pressure Sensor data drifted low 5 V Sensor Supply Circuit - Test
3511-21 Engine Exhaust Gas Recirculation Outlet Pressure Sensor data drifted low 5 V Sensor Supply Circuit - Test
Follow this check list to see if it can help you find the problem. If you need more help, please feel free to ask. I will be glad to help all I can.
E1045-2 Low Intake Manifold Pressure - Derate Intake Manifold Air Pressure Is Low
Intake Manifold Air Pressure Is Low
The Electronic Control Module (ECM) monitors the intake manifold air pressure. The following events are associated with low intake manifold air pressure:
E1045-2 Low Intake Manifold Pressure - Derate This parameter is a variable value that is calculated by the ECM. The resulting value is dependent on the operating conditions of the engine.
Intake air filter
Air intake system
Intake Air Filter
Check the air filter restriction indicator, if equipped.
Ensure that the air filter is clean and serviceable.
If necessary, replace the air filter element. Refer to the Operation and Maintenance Manual, "Engine Air Cleaner Element - Replace".
Check that the fault has been eliminated.
If the fault has not been eliminated, proceed to "Air Intake System".
Air Intake System
Check the air intake system for the following defects:
Damage to the air intake ducts and hoses
Loose connections and air leaks
Make all necessary repairs to the engine.
Ensure that the repairs have eliminated the fault.
If the fault has not been eliminated, proceed to "Wastegate Regulator".
Use the electronic service tool to check for diagnostic trouble codes that relate to the wastegate regulator. Rectify the cause of any related codes. Refer to Troubleshooting, "Diagnostic Trouble Codes".
Ensure that any repairs have eliminated the fault.
If the fault has not been eliminated, proceed to "Turbocharger".
Note: The turbocharger that is installed on the engine is a nonserviceable item. If any mechanical fault exists, then the turbocharger must be replaced.
Check that the compressor housing for the turbocharger is free of dirt and debris.
Check that the turbine housing for the turbocharger is free of dirt, debris, damage, and oil deposits.
Check that the turbine wheel rotates freely in the turbocharger. Make sure that the compressor wheel rotates with the turbine wheel.
If necessary, replace the turbocharger. Refer to Disassembly and Assembly, "Turbocharger - Remove" and Disassembly and Assembly, "Turbocharger - Install".
Check that any repairs have eliminated the fault. If the fault is still present, contact the Technical Communicator at a Cat dealer.