Ascender 2WD L6-4.2L (2003)
Spark Plug: Customer Interest
Ignition System - SES Lamp ON/DTC P0300 Set/Misfire
TSB SB04-01-S002
Service Engine Soon/Check Engine Light
Illuminated, Misfire or Roughness, DTC
P0300 Set (Replace Spark Plugs)
Light Duty ASCENDER 2003 Bulletin Engine 06/01/04
Service Engine Soon/Check Engine Light Illuminated, Misfire or Roughness, DTC P0300 Set (Replace Spark Plugs)
ISSUE DATE: JUNE 2004
Affected Vehicles
2003-2004 Isuzu Ascender (US/UT) models equipped with 4.2L engines (RPO: LL8) built within the VIN breakpoints shown.
Service Information
Condition:
Some owners may comment on engine roughness, misfire or illumination of the Service Engine Soon/Check Engine Light.
Possible Cause:
Upon investigation, the technician will find a DTC P0300, some of these vehicles may have been built with spark plugs that misfire. If a spark plug
misfires, it could result in illumination of the Service Engine Soon Light/Check Engine Light and/or engine misfire and roughness.
Correction:
Use P0300 diagnostics in the Service Manual to identify the source of the concern. If the concern is determined to be a spark plug, replace the spark plug
and inspect for date code.
NOTE:
There will be a 6-digit number stamped on the spark plug. The first 3 digits are the date code.
Service Procedure
Inspect the spark plug for a date code (see figure 1).
203 = Date Code
3 = Year
1 = Line
1 = Shift
^
If the date code on the spark plug is 154, 155, or 156, REPLACE ALL OF THE SPARK PLUGS.