Engine Controls - MIL ON/DTC P0420 Set

12-052

September 14, 2012

Applies To:
2006-07 Accord L4 - KL only

2006-07 Accord L4 (KL only): MIL Comes On With DTC P0420

SYMPTOM

The MIL is on, and DTC P0420 (catalyst system efficiency below threshold) is stored.

PROBABLE CAUSE

The ECM/PCM software may misinterpret sensor inputs as a deteriorated catalytic converter.

CORRECTIVE ACTION

Update the ECM/PCM software, and check the three- way catalytic converter.

WARRANTY CLAIM INFORMATION





The normal warranty applies.

Failed Part: P/N 37820-RAD-L81

Defect Code: 03214

Symptom Code: 03203

Skill Level: Repair Technician

SOFTWARE VERSION

HDS Software Version: 3.003.006 or later.

HDS Control Module (CM) Update:

Database Update 14-MAR-2012 or later.

NOTE:
To avoid an incorrect repair that would not be covered under warranty, use the software version listed above or a later version.





The updated PGM-FI software program IDs and P/Ns are listed below. If the HDS and MVCI is loaded with the latest software, and it displays No Update Needed during the update, the software for this service bulletin is already installed.

REPAIR PROCEDURE

1. To determine whether the vehicle is a KL model:

Online, click on Service, and select Vehicle Information, then VIN Inquiry. Enter the VIN, then under Vehicle Information check the Emission Type.

2. Update the ECM/PCM. Refer to Service Bulletin 01-023, Updating Control Units/Modules.

3. Clear the DTC with the HDS, and leave the HDS connected.

4. Start the engine. Hold the engine speed at 3,000 rpm without load (in neutral) until the radiator fan comes on, then let it idle. Verify that the ECT sensor is above 158°F (70°C).

5. Test-drive the vehicle in 5th gear, between 45 and 65 mph, for at least 5 minutes, with the cruise control set, to warm up the catalytic converter.

6. Monitor the OBD STATUS for DTC P0420 in the DTCs MENU with the HDS while driving.

Does the screen indicate PASSED?

YES - The vehicle is OK at this time.

NO - If the screen indicates EXECUTING, keep driving until a result appears. If the screen indicates OUT OF CONDITION, continue driving under the conditions noted in step 4. If the screen indicates FAILED, replace the three-way catalytic converter.

NOTE:
In most cases, DTC P0420 is caused by the ECM software. In rare cases, the three-way catalytic converter needs to be replaced.





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