Amanti V6-3.8L (2007)
Oxygen Sensor: All Technical Service Bulletins
Engine Controls - Runs Rough/Hesitation/MIL ON
Model: Sedona[VQ], Amanti[GH], Sorento[BL]
Group: Fuel System(14)
Number: KT2008051302
Date: Tuesday, May 13, 2008
Area N. America
Subject:
Sedona (VQ), Amanti (GH) or Sorento (BL) O2 Sensor (HO2S) Codes (Engine - 041)
Description
Some customers of 2006 - 2007 Sedona (VQ), 2007 Amanti (GH), or 2007 Sorento (BL) may experience a concern of a check engine light (MIL) being
ON, which may be accompanied by engine hesitation and/or rough uneven engine running. This concern may be related to a faulty O2 sensor (HO2S).
This TSB addresses faulty HO2S, which may be the cause of the customer concern, and describes when repair is necessary.
NOTICE:
Do NOT erase fault codes until Freeze Frame data has been recorded! A printed copy of the Freeze Frame data must be attached to the workshop
copy of the repair order.
Description
Some vehicles equipped with Lambda engines may have a faulty upstream HO2S that may cause misfire to occur. To a lesser extent, some similarly
equipped engines may have a faulty downstream HO2S, however this will not cause misfire. To conclusively determine when a HO2S is faulty and
causing misfire to occur, you need to closely examine the engine managements "Freeze Frame" data.
In the affected vehicles, for an upstream HO2S to have caused misfire, "Freeze Frame" data will typically show approximately -20% (negative 20%) or
more Short and/or Long Term Fuel Trim on one bank and P0300 - P0306 code(s). In explanation, the faulty upstream HO2S falsely commands
Short/Long Term Fuel Trim to reduce the fuel mixture (lean) on one bank, which then results in misfire.
NOTICE:
A downstream HO2S will not falsely affect Short/Long Term Fuel Trim enough to cause misfire to occur.
Be aware that a faulty upstream O2 sensor may cause a downstream O2 sensor (on that same bank) to set codes. A downstream HO2S should only be
replaced when a downstream HO2S code set, and is not accompanied by an upstream HO2S code or "Freeze Frame" data showing approximately -20%
(negative 20%) or more Short and/or Long Term Fuel Trim.
NOTICE:
When a downstream HO2S sets code,s, it may be correctly responding to a lean condition caused by negative Short and/or Long Term Fuel Trim,
which may have been caused by a faulty upstream HO2S on that same bank.
