Catalytic Converter - California

Replace the California-spec catalytic converter assembly on a 2012-2017 Toyota Camry 2.5L I4, including removal and reinstallation of oxygen sensors and exhaust connections.

Warnings

Tools required

Parts

• California-spec catalytic converter assembly × 1 — Use CARB-compliant OEM or approved aftermarket
• Exhaust flange gasket (manifold to cat) × 1 — Use OEM specification
• Exhaust flange gasket (cat to mid-pipe) × 1 — Use OEM specification
• Exhaust hanger isolators × 2 — Replace if damaged

Preparation

1. Ensure engine and exhaust system are completely cold to the touch
2. Park vehicle on level surface, engage parking brake, and place wheel chocks behind rear wheels
3. Raise front of vehicle with floor jack and support securely on jack stands rated for vehicle weight
4. Spray all exhaust flange bolts and oxygen sensor threads with penetrating oil and let soak for 15-30 minutes
5. Disconnect negative battery terminal to prevent oxygen sensor fault codes during replacement

Procedure

1. 1

   Remove engine splash shield and heat shields
   Remove the plastic engine splash shield from underneath the vehicle using 10mm socket. Remove any heat shields covering the catalytic converter using 10mm socket, noting mounting locations for reassembly.
   Torque spec

   Heat Shield Bolts10 Nm (7 lb-ft)
2. 2

   Disconnect upstream oxygen sensor
   Locate the upstream (pre-cat) oxygen sensor on the exhaust manifold side of the catalytic converter. Disconnect the electrical connector by pressing the release tab. Using a 22mm oxygen sensor socket, carefully unthread the sensor in a counterclockwise direction. Remove sensor completely and inspect threads for damage.
   ⚠Use steady, even pressure when removing oxygen sensor. If sensor is seized, apply more penetrating oil and heat cycle may be necessary.
   Torque spec

   O2 Sensor45 Nm (33 lb-ft)
3. 3

   Disconnect downstream oxygen sensor
   Locate the downstream (post-cat) oxygen sensor on the outlet side of the catalytic converter. Disconnect the electrical connector. Using the 22mm oxygen sensor socket, remove the sensor in a counterclockwise direction. Set aside with upstream sensor.
   Torque spec

   O2 Sensor45 Nm (33 lb-ft)
4. 4

   Support catalytic converter
   Position a floor jack or suitable support under the catalytic converter to prevent it from falling when fasteners are removed. Ensure support is stable and positioned to allow removal of converter once fasteners are loosened.
5. 5

   Remove upper exhaust flange connection
   Locate the two-bolt flange connection between the exhaust manifold and catalytic converter inlet. Using 14mm socket, remove both flange bolts and spring washers. Separate the flange connection slightly and remove the old gasket. Inspect manifold flange surface for damage or warping.
   Torque spec

   Exhaust Flange Bolts45 Nm (33 lb-ft)
6. 6

   Remove lower exhaust flange connection
   Locate the two-bolt flange connection between the catalytic converter outlet and the front exhaust pipe. Using 14mm socket, remove both flange bolts and spring washers. Separate the flange connection and remove the old gasket.
   Torque spec

   Exhaust Flange Bolts45 Nm (33 lb-ft)
7. 7

   Disconnect exhaust hangers
   Locate the rubber exhaust hanger isolators supporting the catalytic converter assembly. Using a prying motion, disconnect the hangers from their mounting points. Note hanger positions for reassembly.
   Torque spec

   Hanger Bolts20 Nm (15 lb-ft)
8. 8

   Remove catalytic converter
   Carefully lower the catalytic converter assembly from the vehicle using the support jack. Guide oxygen sensor wiring through any mounting clips as converter is removed. Inspect removed converter for physical damage, internal rattling, or substrate failure.
9. 9

   Clean and prepare mounting surfaces
   Using a wire brush, thoroughly clean both flange surfaces on the exhaust manifold and front pipe. Remove all old gasket material, carbon deposits, and corrosion. Ensure flange surfaces are flat and free of debris. Inspect studs for damage or excessive corrosion.
10. 10

    Install new catalytic converter
    Position new California-spec CARB-compliant catalytic converter into place using support jack. Verify correct orientation with upstream side toward manifold. Install new flange gasket at manifold connection and align converter inlet flange. Do not fully tighten fasteners yet.
    ℹ️Verify the new converter displays proper CARB Executive Order number and is legal for sale and use in California.
11. 11

    Install lower flange connection
    Install new flange gasket between catalytic converter outlet and front exhaust pipe. Align flange holes and install both flange bolts with spring washers. Apply anti-seize compound to bolt threads before installation. Hand-tighten bolts, then torque to specification in a cross-pattern.
    Torque spec

    Exhaust Flange Bolts45 Nm (33 lb-ft)
12. 12

    Install upper flange connection
    Ensure new gasket is properly seated at manifold connection. Install both flange bolts with spring washers. Apply anti-seize compound to bolt threads. Hand-tighten bolts, then torque to specification in a cross-pattern.
    Torque spec

    Exhaust Flange Bolts45 Nm (33 lb-ft)
13. 13

    Reconnect exhaust hangers
    Reinstall exhaust hanger isolators to their mounting points. Replace any torn or damaged rubber isolators with new parts. Ensure converter is properly supported and aligned with no binding or stress on connections.
    Torque spec

    Hanger Bolts20 Nm (15 lb-ft)
14. 14

    Install oxygen sensors
    Apply a thin coat of anti-seize compound to the threads of both oxygen sensors, being extremely careful not to get any compound on the sensor tip or element. Thread each sensor by hand into their respective bungs until hand-tight. Using 22mm oxygen sensor socket and torque wrench, tighten both sensors to specification. Reconnect both electrical connectors ensuring they click securely.
    ⚠Apply anti-seize ONLY to sensor threads, never to the sensor element. Contamination will cause sensor failure and false readings.
    Torque spec

    O2 Sensor45 Nm (33 lb-ft)
15. 15

    Reinstall heat shields and splash shield
    Reinstall all heat shields in their original positions and secure with fasteners. Torque heat shield bolts to specification. Reinstall engine splash shield and secure all mounting fasteners.
    Torque spec

    Heat Shield Bolts10 Nm (7 lb-ft)

Reassembly

1. Reconnect negative battery terminal
2. Lower vehicle from jack stands
3. Start engine and allow to reach operating temperature while monitoring for exhaust leaks at all connection points
4. Check for proper oxygen sensor operation using scan tool if available

Verification

• Inspect all flange connections for exhaust leaks while engine is running - no visible smoke or hissing sounds should be present
• Verify no exhaust odor is present in cabin during operation
• Check that catalytic converter is not contacting frame, body panels, or suspension components
• Use scan tool to verify both oxygen sensors are reporting proper voltages and switching patterns
• Confirm no check engine light or catalyst-related diagnostic codes are present
• Test drive vehicle to verify normal operation and no exhaust noise or vibration
• Re-check all fastener torque values after initial heat cycle if possible

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