Test Procedure
- RA1 PRELIMINARY DIAGNOSIS FOR DIAGNOSTIC TROUBLE CODE (DTC) P0420 OR P20EE
Are DTCs P0420, P20EE or P24FE present?
Yes No GO to RA2. Unable to duplicate the condition. CHECK for a loose connection, and damaged or corroded terminals. WIGGLE the harness attempting to recreate the concern. REPAIR as necessary.
RETURN to SYMPTOM CHARTS for further direction. - RA2 CHECK FOR OTHER DTCS
- Check for self-test DTCs.
Are any other DTCs present?
Yes No DISREGARD the current diagnostic trouble code (DTC) at this time. DIAGNOSE the next DTC. GO to DIAGNOSTIC TROUBLE CODE (DTC) CHARTS AND DESCRIPTIONS . GO to RA3. - RA3 CHECK FOR LEAKS IN THE EXHAUST SYSTEM
- Visually inspect the fuel vaporizer system for leaks or a plugged fuel vaporizer glow plug.
- Visually inspect the oxidation catalytic converter (OC) and the exhaust gas temperature (EGT) sensors for the following:
- correct connection at the exhaust tube fittings
- correct connection at the sensors exhaust ports
- leaks, cracks, or punctures
Is a concern present?
Yes No REPAIR as necessary.
Clear the PCM DTCs. REPEAT the self-test.GO to RA4. - RA4 CHECK THE FUEL AND REDUCTANT QUALITY
- Verify the fuel level, grade, and quality is sufficient to support normal operation of the engine. Refer to DIAGNOSTIC PROCEDURES and carry out the Sufficient Clean Fuel Test.
- Check with the customer to verify the use of ultra low sulfur diesel fuel.
- Check the reductant fluid level and quality. Refer to ENGINE CONTROL COMPONENTS , Selective Catalytic Reduction (SCR) Catalyst for additional information.
Is a concern present?
Yes No REPAIR as necessary. ADVISE the customer of the correct fuel type required for this vehicle.
Clear the PCM DTCs. REPEAT the self-test.GO to RA5. - RA5 IDENTIFY THE CUSTOMER'S DRIVING HABITS NOTE: Some vehicle operating conditions may cause a high temperature condition before the OC. This condition limits the amount of temperature increase that occurs across the OC and may cause the DTC to set.
- Ignition OFF.
- Check with the customer for the following conditions:
- excessive trailer weight
- steep uphill grade operation
- high engine load operation
- high ambient temperature operation
Is the vehicle consistently operated under high load or high temperature conditions?
Yes No ADVISE the customer of the conditions that may cause the DTC.
Clear the PCM DTCs. REPEAT the self-test.GO to RA6. - RA6 CHECK FOR EXCESSIVE ENGINE OIL CONSUMPTION
- Carry out the oil consumption test. For additional information on excessive engine oil consumption. Refer to the appropriate Engine System - General Information article, Excessive Engine Oil Consumption.
Is a concern present?
Yes No PAIR as necessary.
Clear the PCM DTCs. REPEAT the self-test.INSTALL a new OC. REFER to the appropriate Exhaust System article.
CARRY OUT the diesel particulate filter manual regeneration with the scan tool. REFER to SCAN TOOL SETUP AND FUNCTIONALITY .
CARRY OUT the Diesel Particulate Regeneration System DPF Parameter Reset function on the scan tool. REFER to RESETTING THE DIESEL PARTICULATE FILTER PARAMETER . CARRY OUT the Reset And Clear The Specified Function Oxidation Catalyst and the Initialize Selective Catalytic Reductant SCR Learning on the scan tool. REFER to CLEAR THE CONTINUOUS DIAGNOSTIC TROUBLE CODES (DTCS) AND RESET THE EMISSION MONITORS INFORMATION IN THE POWERTRAIN CONTROL MODULE (PCM) . CARRY OUT the Drive Cycle Procedure. REFER to DRIVE CYCLES .
Clear the PCM DTCs. REPEAT the self-test.