Millenia S V6-2.3L DOHC (Miller cycle) (2000)
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Oxygen Sensor: All Technical Service Bulletins
Engine Controls - MIL ON/O2 Sensor DTC's Stored
01-003/01
MIL ON - DTCs P0420, P0421, P0430, P0431
APPLICABLE MODEL(S)/VINs:
All 1997-2000 Millenia S.
DESCRIPTION
Some vehicles may exhibit MIL illumination with DTC(s) P0420/0421 or P0430/0431 stored in memory with no driveability concerns present. This
condition may be caused by an overly sensitive rear oxygen sensor(s), which falsely indicates an emissions concern and a DTC to be stored.
Customers having this concern should have their vehicle repaired using the following procedure.
REPAIR PROCEDURE
1.
Verify customer concern.
2.
Confirm FFD and stored DTC(s).
^
If DTCs P0420/0421 or P0430/0431 are indicated, proceed to STEP 4.
^
If any DTCs are indicated other than P0420/0421 or P0430/0431, perform the appropriate repair for those DTC(s) according to the appropriate
troubleshooting section of the Workshop Manual and proceed to STEP 3.
3.
Reconfirm FFD and stored DTC(s).
^
If DTCs P0420/0421 or P0430/0431 are now present, proceed to STEP 4.
^
If no DTC(s) are present, return vehicle to customer.
4.
Replace rear 02 sensor only on the side that the MIL and DTC indicates. Refer to EXHAUST SYSTEM REMOVAL/INSTALLATION [KJ] in
the Workshop Manual section 01-15B.
^
DO NOT replace both left and right side 02 sensors at the same time unless stored DTC (s) indicate both sides have concern.
^
DTC(s) P0420/0421 indicates right side 02 sensor. DTC(s) P0430/0431 indicates left side (closest to radiator) 02 sensor.
5.
Confirm the switching ratio of the W-U TWC is greater than 2 to 1, by using the NGS tester and monitoring according to 2000 Workshop Manual
section 01-16B.
^
If inversion ratio is greater than 2 to 1, repair is completed, proceed to STEP 7.
^
If inversion ratio is less than 2 to 1, proceed to STEP 6.
6.
Replace W-U TWC according to EXHAUST SYSTEM REMOVAL/INSTALLATION [KJ] in the Workshop Manual section 01 - 15B.
7.
Verify repair.
PARTS INFORMATION
