MCS Control Panel Diagnostic Trouble Codes
The MCS control panel is able to display Diagnostic Trouble Codes (DTC's). If a fault generates a DTC, the relevant lamp status will trigger an alarm in the controller which will be shown on the LCD display. To interrogate a code, press and hold the log button. The Diagnostic Messages (DM) section will display the code with the relevant Suspect Parameter Number (SPN) and Failure Mode Indicator (FMI). For a list of possible codes, refer to Troubleshooting, "Diagnostic Trouble Codes (MCS Control Panel Diagnostic Trouble Codes)".
Engine Diagnostic Trouble Codes
The engine Electronic Control Module (ECM) can detect faults in the electronic system and with engine operation. A self-diagnostic check is also performed whenever power is applied to the ECM. For a list of possible codes, refer to Troubleshooting, "Diagnostic Trouble Codes (Engine Diagnostic Trouble Codes)".
When a fault is detected, a diagnostic trouble code (DTC) is generated. Each DTC has a lamp status assigned to the code, according to the severity. The possible lamps include Malfunction Indicator (MIL), Amber warning (AWL), Red Stop (RSL) and Protection (Protect). The DTC's conform to the SAE J1939 standard.
Diagnostic Trouble Code - When a fault in the electronic system is detected, the ECM generates a diagnostic trouble code. The diagnostic trouble code indicates the specific fault in the circuitry.
Diagnostic codes can have two different states:
- Active
- Logged
Active Code - An active diagnostic code indicates that an active fault has been detected by the control system. Active codes require immediate attention. Always service active codes prior to servicing logged codes.
Logged Code - Many generated codes are stored in the permanent memory of the ECM. The codes are logged for 100 operating hours unless a code is cleared by use of the electronic service tool.
Logged codes may not indicate that a repair is needed. The fault may have been temporary. The fault may have been resolved since the logging of the code. If the system is powered, an active diagnostic trouble code may be generated whenever a component is disconnected. When the component is reconnected, the code is no longer active. Logged codes may be useful to help troubleshoot intermittent faults. Logged codes can also be used to review the performance of the engine and the electronic system.