Catalytic Converter System Acura TL IV

Scheme 1

DTC P0420: Rear Bank Catalyst System Efficiency Below Threshold (Bank 1); DTC P0430: Front Bank Catalyst System Efficiency Below Threshold (Bank 2)

Note. Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ) If some of the DTCs listed below are stored at the same time as DTC P0420 and/or P0430*, troubleshoot those DTCs first, then recheck for DTC P0420 and/or P0430* P0137, P0138, P0157, P0158 Secondary HO2S (Sensor 2) P0141, P0161 Secondary HO2S (Sensor 2) heater Poor quality fuel can cause these DTCs Information marked with an asterisk (*) applies to the front bank (Bank 2)

1. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode
2. Clear the DTC with the HDS
3. Start the engine Hold the engine speed at 3,000 rpm without load (in P or N) until the radiator fan comes on, then let it idle
4. Test-drive under these conditions Engine coolant temperature (ECT SENSOR 1) above 158°F (70°C) A/T in D, M/T in 4th Vehicle speed between 45-75 mph (72-120 km/h) for 5 minutes or more with cruise control set Vehicle speed between 55-75 mph (88 - 120 km/h) for 10 seconds, then decelerate (with throttle fully closed) Repeat this 3 times or more Maintain the vehicle speed at 55 mph (88 km/h) for 5 minutes or more with cruise control set
5. Monitor the OBD STATUS for DTC P0420 and/or P0430* in the DTCs MENU with the HDS Does the screen indicate EXECUTING? YES -Go to step 6 NO -If the screen indicates OUT OF CONDITION, go to step 4 and recheck If the screen indicates PASSED, intermittent failure, the system is OK at this time If the screen indicates FAILED, go to step 8 and recheck
6. Continue test driving until a result comes on
7. Monitor the OBD STATUS for DTC P0420 and/or P0430* in the DTCs MENU with the HDS Does the screen indicate FAILED? YES -Go to step 8 NO -If the screen indicates PASSED, intermittent failure, the system is OK at this time If the screen indicates EXECUTING, keep driving until a result comes on If the screen indicates OUT OF CONDITION, go to step 4 and recheck
8. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the ON mode
9. Replace the WU-TWC For DTC P0420, replace the rear WU-TWC (Bank 1) (see «REAR (BANK 1)»(/acura/tl/iv-2008-2011/remont/auxiliary-emission-control-systems/#catalytic-converter-system) ) For DTC P0430, replace the front WU-TWC (Bank 2) (see «WARM UP TWC REMOVAL/INSTALLATION»(/acura/tl/iv-2008-2011/remont/auxiliary-emission-control-systems/#catalytic-converter-system) )
10. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode
11. Reset the PCM with the HDS
12. Do the PCM idle learn procedure (see «PCM IDLE LEARN PROCEDURE»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#idle-control-system__pcm-idle-learn-procedure) )
13. Test-drive for about 10 minutes, continually changing the vehicle speed
14. Check the DATA MONITOR CONDITION B1 (B2)* in the DATA LIST with the HDS Is the condition OK? YES -Go to step 15 NO -Go to step 13 and recheck
15. Test-drive under these conditions Engine coolant temperature (ECT SENSOR 1) above 158°F (70°C) A/T in D, M/T in 4th Vehicle speed between 55-75 mph (88 - 120 km/h) for 10 seconds, then decelerate (with throttle fully closed) Repeat this 3 times or more Maintain the vehicle speed at 55 mph (88 km/h) for 5 minutes or more with cruise control set
16. Continue test driving until a result comes on
17. Check for Pending or Confirmed DTCs with the HDS Is DTC P0420 and/or P0430* indicated? YES -Check the fuel quality, then go to step 1 NO -Go to step 18
18. Monitor the OBD STATUS for DTC P0420 and/or P0430* in the DTCs MENU with the HDS Does the screen indicate PASSED? YES -Troubleshooting is complete If any other Pending or Confirmed DTCs were indicated in step 17, go to the indicated DTCs troubleshooting NO -If the screen indicates FAILED, check the fuel quality, then go to step 1 If the screen indicates EXECUTING, keep driving until a result comes on If the screen indicates OUT OF CONDITION, go to step 15

Scheme 2

1. Remove the No 2 the ignition coil and the ignition coil heat insulator
2. Remove the front A/F sensor (Sensor 1) (see «A/F SENSOR REPLACEMENT»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#pgm-fi-system__af-sensor-replacement) ) and the front secondary HO2S (Sensor 2) (see «SECONDARY HO2S REPLACEMENT»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#pgm-fi-system__secondary-ho2s-replacement) )
3. Remove the exhaust pipe A mounting nuts (front WU-TWC side), J35Z6 engine (see «EXHAUST PIPE AND MUFFLER REPLACEMENT»(/acura/tl/iv-2008-2011/remont/mechanical/#intake-manifold-and-exhaust-system__exhaust-pipe-and-muffler-replacement) ), J37A4 engine (see «EXHAUST PIPE AND MUFFLER REPLACEMENT»(/acura/tl/iv-2008-2011/remont/mechanical/#intake-manifold-and-exhaust-system__exhaust-pipe-and-muffler-replacement) )
4. Remove the EGR pipe (see «EGR VALVE REPLACEMENT»(/acura/tl/iv-2008-2011/remont/auxiliary-emission-control-systems/#egr-system) )
5. Remove the A/C condenser fan assembly (see «FAN, FAN MOTOR, AND SHROUD REMOVAL AND INSTALLATION»(/acura/tl/iv-2008-2011/remont/cooling-system-mechanical/#cooling-system) ) and the radiator upper bracket/cushion (see «FAN, FAN MOTOR, AND SHROUD REMOVAL AND INSTALLATION»(/acura/tl/iv-2008-2011/remont/cooling-system-mechanical/#cooling-system) )
6. Remove the front WU-TWC bracket, then carefully remove the front WU-TWC
7. Carefully install the front WU-TWC with a new gasket and new self-locking nuts Tighten the nuts in a crisscross pattern in two or three steps
8. Install the parts in the reverse order of removal

Scheme 3

1. Remove the strut brace (see «FRAME BRACE REPLACEMENT»(/acura/tl/iv-2008-2011/remont/frames-subframes-crossmembers/#frame) )
2. Remove the rear A/F sensor (Sensor 1) (see «A/F SENSOR REPLACEMENT»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#pgm-fi-system__af-sensor-replacement) ) and the rear secondary HO2S (Sensor 2) (see «SECONDARY HO2S REPLACEMENT»(/acura/tl/iv-2008-2011/remont/testing-diagnostics/#pgm-fi-system__secondary-ho2s-replacement) ).
3. Remove the P/S heat shield (see step 14 on «REMOVAL»(/acura/tl/iv-2008-2011/remont/electronic-steering/#power-steering-system) )
4. Remove exhaust pipe A, J35Z6 engine (see «EXHAUST PIPE AND MUFFLER REPLACEMENT»(/acura/tl/iv-2008-2011/remont/mechanical/#intake-manifold-and-exhaust-system__exhaust-pipe-and-muffler-replacement) ), J37A4 engine (see «EXHAUST PIPE AND MUFFLER REPLACEMENT»(/acura/tl/iv-2008-2011/remont/mechanical/#intake-manifold-and-exhaust-system__exhaust-pipe-and-muffler-replacement) ).
5. Remove the intermediate shaft (see «INTERMEDIATE SHAFT REMOVAL»(/acura/tl/iv-2008-2011/remont/axle-shafts/#drivelineaxle) )
6. Remove the rear WU-TWC bracket, then carefully remove the rear WU-TWC
7. Carefully install the rear WU-TWC with a new gasket and new self-locking nuts Tighten the nuts in a crisscross pattern in two or three steps
8. Install the parts in the reverse order of removal

Scheme 4

1. Raise the vehicle on a lift
2. Remove the exhaust pipe hangers (A)
3. Remove the under floor TWC (B)
4. Remove the converter cover (C)
5. Install the parts in the reverse order of removal with new gaskets (D) and new self-locking nuts (E)

Scheme 5

Scheme 6

1. Raise the vehicle on a lift
2. Remove the exhaust pipe hangers (A)
3. Remove the under-floor TWC (A)
4. Remove the converter cover (B)
5. Install the parts in the reverse order of removal with new gaskets (C) and new self-locking nuts (D) and(E)

See also:
• GENERAL TROUBLESHOOTING INFORMATION
• PCM IDLE LEARN PROCEDURE
• A/F SENSOR REPLACEMENT
• SECONDARY HO2S REPLACEMENT
• EXHAUST PIPE AND MUFFLER REPLACEMENT
• EGR VALVE REPLACEMENT
• FAN, FAN MOTOR, AND SHROUD REMOVAL AND INSTALLATION
• FRAME BRACE REPLACEMENT
• REMOVAL
• INTERMEDIATE SHAFT REMOVAL
• REAR (BANK 1)