BULLETIN NUMBER:
WB11-X-001A

IMPORTANT SERVICE
INFORMATION FOR:

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SERVICE MANAGER

ISSUE DATE:
OCTOBER 2023

SERVICE ADVISOR
WARRANTY PERSONNEL

GROUP:
ENGINE

CONTROL MODULE REPROGRAMMING – ISUZU POLICY - ENGINE AND
TRANSMISSION SERIAL NUMBERS
AFFECTED VEHICLES
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All Isuzu N-Series
All GMC and Chevrolet W-Series
All Isuzu F/H-Series
All GMC and Chevrolet C/T-Series equipped with Isuzu diesel
engines.

This bulletin supersedes warranty bulletin WB11-X-001. This bulletin is being
revised to update content. Please disregard previous bulletin WB11-X-001.
INFORMATION
POLICY
The following information is provided to clearly explain Isuzu’s policy for control module
(engine, transmission, antilock brake, instrument panel, body control, power interface,
etc.) reprogramming. Control module calibrations are regularly updated for many
reasons. These reasons may include, but are not limited to: model year change, software
corrections, certification compliance, product improvement and specific application
requirements. However, the mere existence of a newer control module calibration does
not necessarily mean that warranty coverage exists or that the calibration must be
installed. It is not our policy to update control modules, under warranty or after warranty,
based solely on the availability of a newer calibration file. Below are our guidelines for
reprogramming control modules.
1. Acceptable reasons for reprogramming a control module:
a. Control module replacement – Some replacement control modules require
reprogramming at time of installation. This also requires DSPM
authorization.
b. Service bulletin direction – In certain cases a service bulletin may be
released identifying a specific complaint that can be addressed by
reprogramming a control module. This type of reprogramming may only be
performed if the customer complains of the specific condition outlined in the
bulletin.
c. Campaign – Specific vehicles may be flagged under a campaign for control
module reprogramming. Refer to IVIS to confirm affected vehicle.

Reprogramming a control module for any reasons other than the ones listed
above is not warrantable. Warranty claims submitted that do not comply
with this policy will result in a warranty claim chargeback.
SERIAL NUMBERS
Certain control modules require the serial number information to be programmed into
them for proper component recognition and operation. Below are images of serial number
plates and their locations to help technicians identify the correct serial number when they
are required for programming.

Engine Serial Number Requirements (ESN)
1. Diesel vehicles over 14K GVW -- MY2014 and later.
a. A 4HK1 ESN is 6 characters long.
2. The ESN is programmed into the ECM for Gasoline and KL8/LC8 (Alternative
Fuel Capable) 2013MY and later.
a. An ESN is not required but is programmed into the ECM on 12K GVW
vehicles.
b. An ESN is required to be programmed into the ECM on 14.5K GVW
vehicles.
c. The Factory Installed ESN is 15 or 16 characters long, depending on the
Model Year
3. 6.0L remanufactured engine ESNs are 8 characters long.
4. The ESN for a 6.6L Gasoline engine is 16 characters long.

Diesel Engines ESN Locations
Engine Serial
Number
EXAMPLE ONLY

4HK1: The engine number is stamped on the 4HK1: Detail
right-side front part of the engine block.

Gasoline Engines ESN Locations

Engine Serial
Number
EXAMPLE ONLY

6.0/6.6 Gasoline Original Equipment:
The engine serial number is located on the
left-side rear part of engine block and the
right-side front part of the oil pan.
Left-side Rear

6.0L Gasoline Original Equipment:
Detail

Engine Serial
Number
EXAMPLE ONLY

6.0 Gasoline Original Equipment:
Right-side Front

6.0 Gasoline Original Equipment:
Detail

Engine Serial
Number
EXAMPLE ONLY

6.6 Gasoline Original Equipment:
Right-side Front

6.6 Gasoline Original Equipment:

6.0L Gasoline Only Remanufactured

6.0L Gasoline Only
Remanufactured Detail

Detail

6.0L Gasoline Alt Fuel (KL8/LC8)

6.0L Gasoline Alt Fuel (KL8/LC8)
Detail

Automatic Transmissions Serial Number Locations

Transmission
Serial Number
EXAMPLE ONLY

6L90, 4L80 Transmissions:
(6) Sequential Serial Number

6L90, 4L80 Transmissions:
Detail

Transmission
Serial Number
EXAMPLE ONLY

A450, A460, A465 Transmissions:
Located on left side

A450, A460, A465 Transmissions:
Detail