Emissions Inspection

This procedure guides you through performing an emissions inspection on a 2007 Ram 3500 with the 5.9L Cummins diesel engine, including visual checks of emissions control components and diagnostic system verification.

Warnings

Tools required

Preparation

1. Ensure vehicle has been driven recently to reach normal operating temperature for OBD-II readiness monitors
2. Park vehicle on level ground and engage parking brake
3. Allow engine and exhaust system to cool completely
4. Have vehicle registration and previous inspection records available for reference

Procedure

1. 1

   Connect OBD-II scan tool
   Locate the OBD-II diagnostic port under the driver's side dashboard, typically near the steering column. Plug in the scan tool and turn the ignition to the ON position without starting the engine. Wait for the scan tool to establish communication with the vehicle's ECM.
2. 2

   Check for diagnostic trouble codes
   Scan for any stored or pending diagnostic trouble codes (DTCs). Record all codes found. Pay special attention to emissions-related codes in the P0xxx range. Verify that the Malfunction Indicator Lamp (MIL/Check Engine Light) is not illuminated on the instrument cluster.
   ℹ️Any stored emissions-related DTCs will typically result in inspection failure
3. 3

   Verify OBD-II readiness monitors
   Check the readiness status of supported OBD-II monitors using the scan tool. On the 2007 heavy-duty Cummins (over 8500 lbs GVWR), the OBD-II monitor set is limited and many monitors are reported as 'Not Supported', which is acceptable. Verify that the supported applicable monitors show 'Ready' status per local requirements.
   ℹ️Most jurisdictions allow one non-continuous monitor to be 'Not Ready' on 2007 models, but requirements vary by state
4. 4

   Inspect fuel cap and evaporative system
   Remove and inspect the fuel cap for damage, cracks, or a worn seal, and reinstall securely. Check the fuel filler neck for damage or corrosion. Note that diesel applications do not use a gasoline-style evaporative (EVAP) emissions system, so no EVAP lines or sealed-cap 'click' verification apply. Inspect fuel supply and return lines for leaks or damage.
   ⚠Diesel fuel vapors are present; avoid open flames
5. 5

   Inspect exhaust system for leaks
   Visually inspect the entire exhaust system from the turbocharger outlet to the tailpipe. Check all connections, flanges, and welded joints for signs of exhaust leaks (soot deposits, rust stains, or damaged gaskets). Pay special attention to the exhaust manifold-to-turbo connection and downpipe connections. If necessary, raise vehicle to inspect underside components.
   ⚠Exhaust components may still be hot even after cooling period; verify temperature before touching
6. 6

   Check catalytic converter presence and condition
   The 2007 5.9L Cummins Ram 3500 was not factory-equipped with a catalytic converter or exhaust aftertreatment device. If your jurisdiction requires verification, confirm the vehicle's original emissions configuration against the underhood emissions label rather than requiring a catalytic converter. Inspect the exhaust system for any aftermarket modifications or removed factory emissions components.
7. 7

   Inspect EGR system components
   Locate the Exhaust Gas Recirculation (EGR) valve on the intake side of the engine. Check that the EGR valve is present and all vacuum lines or electrical connectors are attached. Inspect the EGR cooler and connecting pipes for leaks, damage, or excessive carbon buildup. Verify the EGR valve mounting bolts are secure.
   ℹ️EGR system is a critical emissions component; missing or disconnected parts will result in inspection failure
8. 8

   Inspect crankcase ventilation system
   Check the crankcase ventilation system including the breather filter/separator typically located on the driver's side valve cover. Verify all hoses are connected and not cracked or deteriorated. Check for excessive oil leakage around connections which could indicate system blockage or failure.
9. 9

   Verify turbocharger operation and condition
   Visually inspect the turbocharger housing for cracks or oil leaks. Check that all intake and exhaust connections are secure. While this is primarily a visual check, note any obvious mechanical damage or signs of excessive oil consumption that could affect emissions.
   ℹ️Turbocharger boost control affects emissions; damaged wastegate or boost control solenoid may cause excessive smoke
10. 10

    Check air intake system
    Inspect the air filter housing and verify a clean air filter is installed. Check all intake ducting from the air filter to the turbocharger inlet for cracks, holes, or loose clamps. Verify the intake air temperature sensor is connected. Damaged or disconnected intake components can affect emissions and engine performance.
11. 11

    Visual smoke and emissions check
    If permitted by inspection protocol, start the engine and observe exhaust smoke from the tailpipe. Normal operation should produce minimal visible smoke after initial startup. Excessive black smoke indicates incomplete combustion, white smoke may indicate coolant intrusion, and blue smoke indicates oil burning. Document any abnormal smoke conditions.

Reassembly

1. Ensure fuel cap is properly reinstalled and tightened until it clicks
2. Disconnect scan tool and verify OBD-II port dust cover is reinstalled if equipped
3. Lower vehicle if raised and remove jack stands

Verification

• Confirm no diagnostic trouble codes are present in ECM memory
• Verify Check Engine Light (MIL) is not illuminated with ignition on
• Confirm all required OBD-II readiness monitors show 'Ready' status per local requirements
• Verify no visible exhaust leaks or excessive smoke during engine operation
• Ensure all emissions control components are present, connected, and undamaged
• Document inspection results and any advisory items for vehicle owner

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

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