Visual and functional inspection of emissions control systems to verify compliance with environmental regulations and proper operation of catalytic converter, oxygen sensors, EVAP system, and PCV system.

Warnings

Tools required

Preparation

1. Park vehicle on level surface and allow engine and exhaust system to cool completely
2. Verify vehicle has been driven through complete drive cycle and all readiness monitors show ready status
3. Ensure fuel tank is between 1/4 and 3/4 full for EVAP system testing
4. Gather vehicle registration and previous inspection records if available

Procedure

1. 1

   Connect OBD-II Scanner and Check Readiness
   Locate OBD-II diagnostic port under driver side dashboard below steering column. Connect scanner with ignition OFF. Turn ignition to ON position without starting engine. Check for diagnostic trouble codes (DTCs) and verify all emissions readiness monitors show READY status. Record any pending or stored codes.
   ℹ️All monitors except EVAP and O2 sensor heater must be ready for inspection pass in 2014-2016 models; all monitors must be ready for 2017-2019 models
2. 2

   Inspect Gas Cap and Fuel Filler
   Open fuel door and remove gas cap. Inspect cap gasket for cracks, deterioration, or damage. Check that cap clicks at least 3 times when tightened. Inspect fuel filler neck for damage or corrosion. Use flashlight to check for contamination or blockage.
3. 3

   Inspect EVAP Canister and Hoses
   Locate charcoal canister mounted under vehicle near fuel tank on driver side. Visually inspect canister body for cracks or damage. Check all vacuum hoses connected to canister for cracks, disconnections, or deterioration. Verify canister vent filter is not clogged with debris or mud.
4. 4

   Inspect Purge Valve
   Locate EVAP purge valve on driver side of engine near intake manifold. Inspect electrical connector for corrosion or damage. Check vacuum hoses to purge valve for cracks or loose connections. Listen for clicking sound from valve during engine start-up indicating proper operation.
5. 5

   Inspect PCV System
   Locate PCV valve in valve cover on passenger side of engine. Check that PCV valve hose connects securely to intake manifold. Inspect hose for cracks or oil saturation indicating deterioration. With engine running at idle, disconnect PCV hose from valve cover and verify vacuum suction is present.
   ⚠Engine will run rough when PCV hose is disconnected; reconnect immediately after verifying suction
6. 6

   Inspect Oxygen Sensors
   Locate upstream oxygen sensor in exhaust manifold and downstream sensor after catalytic converter on underside of vehicle. Inspect sensor wiring harnesses for damage, melting, or chafing against exhaust components. Verify electrical connectors are securely attached and show no corrosion. Check that sensors are not loose in threads.
7. 7

   Inspect Catalytic Converter
   Visually inspect catalytic converter from underneath vehicle for external damage, dents, or road debris impact. Check for signs of overheating such as discoloration or warped heat shields. Listen for internal rattling indicating substrate damage. Verify all mounting hardware is secure and heat shields are properly attached.
8. 8

   Inspect Exhaust System for Leaks
   Inspect entire exhaust system from manifold to tailpipe for cracks, holes, or separation at joints. Check exhaust manifold gasket area for evidence of leaks (black soot deposits). Verify all exhaust hangers are intact and system is not contacting body or frame. Pay special attention to flex pipe section forward of catalytic converter.
9. 9

   Inspect Air Intake System
   Open hood and inspect air filter housing for proper sealing and secure mounting. Check air intake ductwork from air box to throttle body for cracks, disconnections, or aftermarket modifications. Verify mass airflow (MAF) sensor electrical connector is secure. Inspect air filter element for excessive dirt or oil contamination.
10. 10

    Perform Functional Test
    Start engine and allow to reach normal operating temperature. Observe scanner data for oxygen sensor switching (upstream should switch rapidly between rich/lean), catalyst efficiency above 95%, and proper fuel trim values (short and long term trims within ±10%). Rev engine to 2500 RPM and verify no excessive smoke from tailpipe. Check that check engine light (MIL) is not illuminated.
    ℹ️Blue smoke indicates oil burning, black smoke indicates rich condition, white smoke indicates coolant burning - all require further diagnosis

Reassembly

1. Disconnect OBD-II scanner and return diagnostic port cover to closed position
2. Ensure gas cap is properly installed and clicks at least 3 times when tightened
3. Close hood and fuel door securely

Verification

• Confirm no diagnostic trouble codes are present and all readiness monitors show READY status
• Verify check engine light (MIL) illuminates during key-on engine-off and extinguishes after engine start
• Confirm no visible smoke from exhaust during idle or acceleration
• Verify no fuel odor present indicating EVAP system leaks
• Test drive vehicle and confirm smooth operation with no hesitation or performance issues

More procedures for this vehicle