BULLETIN NUMBER:
SB24-J-001

IMPORTANT SERVICE
INFORMATION FOR:
 SERVICE MANAGER
 SERVICE ADVISOR
 TECHNICIAN
 PARTS DEPARTMENT
 WARRANTY PERSONNEL

ISSUE DATE:
JULY 2024
GROUP:
ENGINE

DTC 3243 - REPROGRAM ENGINE CONTROL MODULE (ECM)
AFFECTED VEHICLES


2022 – 2024MY Isuzu F-Series
With a vehicle production date prior to 5/22/2024
CONDITION

The vehicle’s Check Engine Malfunction Indicator Lamp (MIL) may be illuminated as
a result of the engine fan clutch being constantly engaged while the engine is running,
thereby setting a DTC 3243 in the Engine Control Module (ECM). Follow the published
diagnostic in the applicable Works h op Manual (WSM) DTC 3243. If no fault can be
found during this normal diagnosis, follow the Service Procedure in this bulletin
to correct the concern.
SERVICE PROCEDURE
1. Contact the local Cummins Certified Service location to have the ECM reprogrammed
per the procedure below.
a. If you (the Isuzu dealer) are also a Cummins Certified Service location, this
procedure should be performed at your location, as you are the closest
Cummins Certified Service location.
b. If you (the Isuzu dealer) are not a Cummins Certified Service location, you
should arrange to have this procedure performed at the closest Cummins
Certified Service location; you can find the closest Cummins Certified
Service location on the web at https://www.cummins.com/locations.
2. Provide the “Procedure” section of this bulletin to the Cummins location to have a
Cummins trained technician reprogram the ECM with the correct Air Conditioning
Pressure Switch setting using the Cummins INSITE tool.
PROCEDURE (to be performed by a Cummins Certified Service location using INSITE)
3. Using the Cummins INSITE tool (version 9.0.0.94 or later), from the Main Screen select
Connect to ECM to establish communication with ECU, and then select Connect. (See
Figure 1.)

Figure 1
4. Select Features and Parameters. (See Figure 2.)

Figure 2

5. Select Fan Control. (See Figure 3.)

Figure 3

6. Select Air Conditioning Pressure Switch Input. (See Figure 4.)

Figure 4

7. Select Disable for Air Conditioning Pressure Switch Input at the drop-down menu.
(See Figure 5.)

Figure 5

8. Select FILE and select Send to ECM. Select OK from the Confirm ECM
Adjustment pop up. (See Figure 6.)

Figure 6

9. Follow the following Cummins INSITE instructions to complete download.
a. Key switch off, then click OK.
b. Wait 100 seconds.
c. Key switch on, then click OK.
10. Confirm all parameters were written successfully. (See Figure 7.)

Figure 7

WARRANTY INFORMATION
For vehicles repaired under warranty, use:
Labor
Code

J8017

Description

ECM REPROGRAM P3243 Fan
Control

Labor
Hours

0.4*

Sublet

Cummins Service
Repair Cost

*Includes 0.1 hours for diagnostic and coordination with Certified Cummins Repair location.