Perform a comprehensive diagnostic scan of all vehicle control modules using an OBD-II scan tool to identify stored fault codes, pending codes, and system readiness status on the 2014 Ram 2500 with 6.7L Cummins Diesel engine.

Warnings

Tools required

Preparation

1. Park vehicle on level ground and set parking brake
2. Turn ignition OFF and ensure all accessories are off
3. Allow vehicle to sit for at least 2 minutes to allow modules to enter sleep mode before beginning scan
4. Verify battery voltage is at least 12.4V for accurate diagnostics
5. Gather vehicle service history and any customer concerns related to warning lights or driveability issues

Procedure

1. 1

   Locate OBD-II Diagnostic Port
   The OBD-II diagnostic port is located under the driver's side dashboard, to the left of the steering column near the hood release. Remove any trim panels if necessary to access the port. Inspect the port for damage, corrosion, or bent pins.
2. 2

   Connect Scan Tool
   Plug the OBD-II scan tool firmly into the diagnostic port until it is fully seated. Ensure the connection is secure. Turn the ignition to the ON/RUN position without starting the engine. The scan tool should power up and establish communication with the vehicle.
3. 3

   Identify Vehicle and Engine
   Allow the scan tool to automatically identify the vehicle or manually input 2014 Ram 2500 with 6.7L Cummins Diesel engine. Verify the VIN matches the vehicle being serviced. Confirm the scan tool recognizes all available control modules including ECM, TCM, ABS, airbag, and body control modules.
4. 4

   Perform Global System Scan
   Initiate a complete vehicle scan to interrogate all control modules. This may take 3-5 minutes depending on scan tool speed. Monitor the scan progress and note any modules that fail to communicate. Document the total number of systems scanned and any communication errors.
5. 5

   Retrieve and Document Fault Codes
   Review all stored diagnostic trouble codes (DTCs), pending codes, and permanent codes from all modules. For each code, document the code number, description, freeze frame data, and failure occurrence count. Pay special attention to Cummins-specific codes in the ECM and transmission codes in the TCM. Note any manufacturer-specific codes that may not be generic OBD-II codes.
6. 6

   Check System Readiness Monitors
   Access the OBD-II readiness monitor status to determine which emission-related monitors have completed their self-tests. For diesel engines, verify the status of the Comprehensive Component Monitor, Fuel System Monitor, and Misfire Monitor if applicable. Note any monitors showing 'Not Ready' status which may indicate recent code clearing or incomplete drive cycles.
7. 7

   Review Live Data Parameters
   Access live data stream from the ECM and observe critical engine parameters with engine OFF/ignition ON: coolant temperature sensor reading, intake air temperature, boost pressure, fuel rail pressure sensor, throttle position, and all oxygen/NOx sensor readings. Compare readings to known good values for a cold engine at rest. Start the engine and monitor live data at idle for 2-3 minutes, observing fuel pressure (typically 5,000-6,000 psi at idle), coolant temperature rise, turbo boost (should be near 0 psi at idle), and EGR valve operation.
8. 8

   Check Diesel Exhaust Fluid System
   Access the DEF system data to verify DEF tank level reading, DEF quality status, DEF heater operation if ambient temperature is cold, and DEF injector performance. Check for any SCR (Selective Catalytic Reduction) system codes or NOx sensor faults. Verify the calculated range until DEF service is required matches the dash display.
9. 9

   Review Diesel Particulate Filter Status
   Check DPF regeneration history including last regeneration date/mileage, total regeneration count, DPF soot load percentage, and DPF pressure differential readings. A high soot load (above 80%) or frequent regeneration requests may indicate underlying issues. Review any active regeneration inhibit conditions.
10. 10

    Document Transmission Data
    Access transmission control module and review transmission fluid temperature, current gear selection, shift adapts, clutch pressure readings, and any transmission-specific codes. For the 68RFE transmission, check line pressure and verify proper communication between ECM and TCM.
11. 11

    Scan ABS and Chassis Systems
    Review ABS module for wheel speed sensor codes, brake system faults, and traction control issues. Check four-wheel drive system module for transfer case codes, shift motor position, and 4WD engagement faults. Verify all wheel speed sensors are reading 0 mph with vehicle stationary.
12. 12

    Create Diagnostic Report
    Save or print a complete diagnostic report from the scan tool including all retrieved codes, freeze frame data, and module information. If scan tool supports it, save a snapshot of the vehicle configuration and current parameters for future reference. Organize findings by priority: Critical faults requiring immediate attention, pending codes that need monitoring, and informational data.
13. 13

    Disconnect Scan Tool
    Turn the ignition OFF. Disconnect the scan tool from the OBD-II port. Inspect the port once more to ensure no pins were damaged during the procedure. Reinstall any trim panels that were removed for access.

Reassembly

1. Ensure OBD-II port area is clean and accessible for future diagnostics
2. Return ignition key and inform customer of findings
3. Update service records with diagnostic scan results and any codes found

Verification

• Confirm scan tool successfully communicated with all expected control modules (minimum 15-20 modules on this vehicle)
• Verify all fault codes and freeze frame data have been properly documented
• Review diagnostic report for completeness and accuracy before presenting findings
• If codes were present, develop diagnostic plan based on code priority and customer concerns
• Verify no new communication errors or codes were set during the scan procedure

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