Rainier AWD L6-4.2L VIN S (2005)
Cowl Moulding / Trim: All Technical Service Bulletins
Ignition System - MIL ON/Misfire DTC's In Wet Weather
Bulletin No.: 06-06-04-048B
Date: January 12, 2007
TECHNICAL
Subject:
4.2L LL8 Engine - Flashing and/or MIL/SES Light, Rough Idle, Misfire(s) DTC(s) P0300, P0301, P0302, P0303, P0304, P0305, P0306 (Install AIP
Seal)
Models:
2004-2007 Buick Rainier
2002-2007 Chevrolet TrailBlazer
2002-2007 GMC Envoy
2002-2004 Oldsmobile Bravada
2005-2007 Saab 9-7X
with Vortec(TM) 4.2L Inline 6 Cylinder Engine (VIN S - RPO LL8)
Supercede:
This bulletin is being revised to add the new part numbers for the Spark Plugs and Ignition Coils. Please discard Corporate Bulletin Number
06-06-04-048A (Section 06 - Engine/Propulsion System).
Condition
Some customers may comment that, after severe weather that includes large amounts of rain in a short period of time, the engine has a rough idle and/or
flashing MIL/SES light. Upon further investigation, there may be the following DTC(s): P0300, P0301, P0302, P0303, P0304, P0305 or P0306.
This condition can be aggravated if the vehicle is parked nose down on an incline during this type of weather. The customer may also comment on repeat
occurrences of this condition because water may be passing over the Air Intake Plenum (AIP).
Cause
The dripping rain water onto the engine cam cover will collect at the coil(s) and may seep past the coil(s) into the spark plug(s) well of the cylinder head
and may affect the operation of the spark plug(s) and coil(s), causing the misfire(s).
Correction
Before replacing the AIP seal, refer to Misfire diagnostics in SI to determine if water intrusion was the cause of the misfire.
Diagnostic Aids for Misfire
Refer to SI for Base Engine Misfire without Internal Engine Noises.
If no trouble found (NTF) using SI document on Base Engine Misfire without Internal Engine Noises, then refer to SI for Misfire DTC(s).
If Misfire diagnostic leads to the removal of the coil(s) and spark plug(s), refer to the following SI Documents:
Air Cleaner Outlet Resonator Replacement
Ignition Coil Replacement Removal Procedure
Spark Plug Replacement
Coil(s) damage from water intrusion will have a film of white chalk build-up on the outside and inside of the spark plug boot to ignition coil(s) assembly.
If present, remove the spark plug(s) and inspect for similar build-up on the outside of the spark plug(s).
If NTF with the coil(s) and spark plug(s), continue on with the Misfire Diagnostic in SI.
Replace any coil and spark plug that has been diagnosed to be damaged from water intrusion. To prevent a reoccurrence, follow repair information
outlined in this bulletin to replace the AIP seal.
