NUT 7X0851 - Caterpillar

Use this procedure in order to troubleshoot a high altitude derate.Probable Causes
Diagnostic codes
Atmospheric pressureRecommended Actions
Note: The procedures have been listed in order of probability. Complete the procedures in the order of the listed test steps.
Table 1
Troubleshooting Test Step    Value    Result    
1. Check for Active Codes and Logged Codes
A. Establish communication between Caterpillar Electronic Technician (ET) and the Electronic Control Module (ECM).
B. Monitor the diagnostic codes on Cat ET. Check for active or logged diagnostic codes. Specifically check for codes that could be associated to atmospheric pressure.
Note: Wait at least 30 seconds in order for diagnostic codes to become active.
C. If the histograms contain derates and no diagnostic codes are present, then the engine is operating normally.
   
Codes
    Result: A code is active or logged.
Repair: Troubleshoot any codes before continuing with this procedure.
Verify that the repair eliminated the problem.
Result: A code is not active or logged.
Proceed to Test Step 2.
   
2. Check the Atmospheric Pressure
A. The engine is being operated in an environment with low atmospheric pressure.
   
Atmospheric Pressure
   
Result: The ECM automatically compensates for engine operation in lower atmospheric pressure. This condition occurs at high altitudes.
The atmospheric pressure is specific for the engine and for the engine rating. The default settings for atmospheric pressure are programmed at the factory.
Refer to Troubleshooting, "Configuration Parameters " for additional information.
   If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).