How to Retrieve and Clear Fault Codes on a Case CX210 Excavator

[MikePhua]

Introduction to the CX210 Diagnostic Interface
The Case CX210 (and CX210C/CX210B models) features a built-in diagnostic system accessible via the instrument panel. It displays current and past fault codes related to engine, hydraulics, sensors, and safety systems. The interface is operated through the Travel Mode, Work Mode, Auto Mode, and Buzzer Stop switches located on the dash.
Accessing the Diagnostic Screens

• Simultaneously press the Travel Mode and Work Mode switches for about 3 seconds to enter the diagnostic menu. This toggles between the standard display and CHK, DIAG, HR, and RST screens .
  
• Use the Auto Mode switch to move between sections like CHK (current conditions), DIAG (fault codes), HR (history), and RST (settings) .
  
• Press the Buzzer Stop switch to scroll down vertically within a screen’s lines .
  

Understanding the Diagnostic Screens

• CHK Screens (CHK1–CHK6): Show live sensor data such as hydraulic pressures (P1, P2), engine RPM, coolant temperature, oil temperature, and indicator of output transistor faults like TR1, TR2, TR3—commonly used to detect short circuits .
  
• DIAG Screens:
  • DIAG1: Current engine fault codes
    
  • DIAG2: Past engine fault codes
    
  • DIAG4: Current machine (excavator systems) fault codes
    
  • DIAG5: Past machine fault codes (e.g. hydraulic sensors, CAN errors) .
    
• HR Screens (HR1–HR12): Store operating hours segmented by mode (engine, travel, work) and temperature bins for coolant, fuel, and hydraulic oil .
  
• RST Screens: Parameters such as auto-idle timing, maximum RPM for hammer mode, altitude compensation settings, and auto power boost can be adjusted or reset here .
  

Erasing Fault Codes and History

• Navigate to DIAG2 or DIAG5, then press and hold the Work Mode switch for about 10 seconds. A buzzer will sound. Turning off the key switch finalizes the reset and clears the codes/history from those screens .
  

Fault Code Examples and Sources
Some common codes (shared across CX210/CX240/CX300 series) are:

• P0193: Fuel Rail Pressure Sensor Circuit High
  
• P0091: Fuel Rail Regulator Control System Low Input
  
• U0101: Lost Communication with Transmission Controller (TCM)
  
• P0113: Intake Air Temperature Sensor High Input
  
• P0335: Crankshaft Position Sensor Circuit Fault
  
• P0087–P0092: Fuel pressure or rail sensor anomalies
  These follow standard powertrain (P) and body (B/U) code convention for CASE machines .
  

Self-Test: Transistor Output (CHK Self-Check)

• Hold the One-Touch Idle button, turn the key switch ON, then release. The controller energizes TR circuits, sounding the buzzer if over-current (short circuit) is detected. TR1–TR3 codes appear in CHK5 or CHK6 screens for diagnostics. Leaving the key on and pressing Travel longer than 10 seconds enters CHK6 display. Turning off the key clears these warnings .
  

Case Scenario: Limp Mode Diagnosis
One owner experienced limp mode with codes:

• 2456, 0101, 0091, 0193, 0000
  

Community input identified those as:

• P0193 (High fuel rail pressure)
  
• P0091 (Fuel rail regulator low input)
  
• U0101 (Lost communication with TCM)
  
• P2456 (DPD differential pressure sensor learning position error) .
  

Terminology Explained

• Fault Code (DTC): Diagnostic Trouble Code indicating a specific system fault.
  
• CHK Screens: Show real-time system status like pressures, temperature, RPM.
  
• DIAG Screens: Historic and live fault code memory for engine and machine systems.
  
• HR Screens: Historical operation metrics and temperature logs.
  
• RST Screens: Configuration and parameter reset menus.
  
• TR1–3 Circuits: Transistor outputs for safety checks—short detection.
  
• One-Touch Idle: Button that holds engine at idle RPM for diagnostics.
  

Summary of Navigation and Use

• Simultaneously press Travel + Work Mode to enter diagnostics.
  
• Use Auto Mode to select CHK/DIAG/HR/RST group.
  
• Scroll with Buzzer Stop or Travel key as indicated.
  
• To erase codes/history, press Work Mode for 10 seconds on DIAG2 or HR1, then switch the key off.
  

Conclusion
By accessing the built-in diagnostic interface using the combination of Travel, Work Mode, Auto Mode, and Buzzer Stop switches, operators can view live system conditions, retrieve stored fault codes, and even reset historical logs. Understanding how to interpret CHK and DIAG screens lets technicians quickly pinpoint sensor or communication faults. For example, codes like P0193 or U0101 give immediate insight into sensors or bus communication errors, enabling targeted repairs and quicker return to service.