TSB200014-012220

1/28/2020
Proper Troubleshooting of Fault Code 7238
Technical Service Bulletin
Technical Service Bulletin: TSB200014
Released Date: 22-Jan-2020
Proper Troubleshooting of Fault Code 7238
Proper Troubleshooting of Fault Code 7238
Warranty Statement
The information in this document has no effect on present warranty coverage or repair practices,
nor does it authorize TRP or Campaign actions.
Contents
Product Affected
ISX12N CM2380 X120B
Issue
Fault Code 7238 “Fuel Control Module - Abnormal Update Rate” is a fault code that indicates loss
of communication on the private J1939 network to the Continuous Flow Valve (CFV) and/or loss of
unswitched power supply to CFV pin 1. When logged in combination with other fault codes, the
other fault codes should be troubleshot first to prevent unnecessary replacement of the CFV.
Verification
If Fault Code 7238 is inactive and older than 25 ECM hours do not troubleshoot.
If Fault Code 7238 is active or inactive with one or more counts less than 25 hours old, look
for other fault codes in Resolution section. If no other faults present, follow troubleshooting
steps for Fault Code 7238.
Pay close attention to CFV, Fuel System Extension Harness, and OEM 31 pin connectors for
connectors not fully seated, pins pushed back, expanded pins, pin corrosion, etc.
Resolution
If Fault Code 7238 is paired with Fault Code 6631, follow troubleshooting steps for Fault Code
441. This failure mode indicates an issue with the unswitched OEM power supply or wiring.
If Fault Code 7238 is paired with Fault Code 3367, follow troubleshooting steps for Fault Code
7239. This failure mode indicates an issue with the FS17B fuel system relay or relay wiring
circuits.
Document History
Date
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Details
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1/28/2020
Proper Troubleshooting of Fault Code 7238
Date
2020-1-16
Details
Module Created
Last Modified: 22-Jan-2020
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