Home ReviewsRefund
Home/Acura/RL/Acura RL II (2004-2008)/Repair manual/Auxiliary Emission Control Systems/Catalytic Converter System
Contents Wiring diagrams Section: Auxiliary Emission Control Systems All sections

Catalytic Converter System Acura RL II

Auxiliary Emission Control Systems 3 illustrations ~795 words

Scheme 60

Scheme 60: Component Location Index
Scheme 60: Component Location Index

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, P2270, P2271, P2272*, P2273*: 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 ON (II).
  2. Clear the DTC with the HDS.
  3. Start the engine. Hold the engine speed at 3,000 RPM without load (in Park or neutral) 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) Transmission in D position Vehicle speed between 45 mph (72 km/h) and 75 mph (120 km/h) for 5 minutes or more with cruise control set 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 - Go to step 4 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 OFF.
  9. Replace the WU-TWC (see «WARM UP TWC REMOVAL/INSTALLATION»(/acura/rl/ii-2004-2008/remont/auxiliary-emission-control-systems/#catalytic-converter-system) ).
  10. Turn the ignition switch ON (II).
  11. Reset the PCM with the HDS.
  12. Do the PCM idle learn procedure (see «PCM IDLE LEARN PROCEDURE»(/acura/rl/ii-2004-2008/remont/engine-control-systems/#idle-control-system__pcm-idle-learn-procedure) ).
  13. Start the engine. Hold the engine speed at 3,000 RPM without load (in Park or neutral) until the radiator fan comes on, then let it idle.
  14. Test-drive for about 10 minutes, continually changing the vehicle speed.
  15. Check the CATA MONITOR CONDITION in the DATA LIST with the HDS. Is the temperature OK? YES - Go to step 16. NO - Go to step 13 and recheck.
  16. Test-drive under these conditions: Engine coolant temperature (ECT SENSOR 1) above 158°F (70°C) Transmission in D position Vehicle speed at 55 mph (88 km/h) for 5 minutes or more with cruise control set
  17. 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 18. NO - Go to step 16 and recheck.
  18. Continue test-driving until a result comes on.
  19. Check for Temporary DTCs or DTCs with the HDS. Is DTC P0420 and/or P0430' indicated? YES - Check for poor connections or loose terminals at the secondary HO2S (sensor 2) and the PCM, then go to step 1 . NO - Go to step 20.
  20. 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 Temporary DTCs or DTCs were indicated in step 19 , go to the indicated DTCs troubleshooting. NO - If the screen indicates FAILED, check for poor connections or loose terminals at the secondary HO2S (Sensor 2) and the PCM, 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 16 .

Scheme 61

Scheme 61: FRONT
Scheme 61: FRONT
  1. Remove the condenser fan shroud (see «RADIATOR AND FAN REPLACEMENT»(/acura/rl/ii-2004-2008/remont/cooling-system-mechanical/#cooling-system) ).
  2. Disconnect the front air fuel ratio (A/F) sensor connector and front secondary heated oxygen sensor (secondary HO2S) connector.
  3. Remove the front WU-TWC.
  4. Install the front WU-TWC, and tighten the nuts in a crisscross pattern in two or three steps.
  5. Install the parts in the reverse order of removal.

Scheme 62

Scheme 62: REAR
Scheme 62: REAR
  1. Remove the intermediate shaft (see «INTERMEDIATE SHAFT REMOVAL»(/acura/rl/ii-2004-2008/remont/axle-shafts/#drivelineaxle) ).
  2. Disconnect the rear air fuel ratio (A/F) sensor connector and rear secondary heated oxygen sensor (secondary HO2S) connector.
  3. Remove the rear WU-TWC bracket, then remove the rear WU-TWC.
  4. Install the rear WU-TWC, and tighten the nuts in a crisscross pattern in two or three steps.
  5. Install the parts in the reverse order of removal.

More articles — Engine