NHTSA ID Number: 10246235
Manufacturer Communication Number: IK2300022
TSB/Document Date: 2023-12-05
Summary
Cabin Heat Coolant Over Boil with fault SPN 5574 FMI 7
Countries: CANADA, UNITED STATES Document ID: 1K2300022
¢| Availability: ISIS, Bus ISIS, NotSIR Revision: 0
Major System ELECTRIC VEHICLE Created: 19/7/2023
Current Language: English Last Modified: 11/7/2023
Knowledge Base Other Languages: NONE Author: Josh Bowman
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Title: Cabin Heat Coolant Over Boil w/SPN 5574 FMI 7 Fault
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Applies To: Electric CE Bus
CHANGE LOG
Please refer to the change log text box below for recent changes to this article:
DESCRIPTION
This document will guide the user through utlizing the proper settings for the cabin heat to mitigate coolant leaking from the
cabin heat surge tank overflow hose.
Please note, this concern is actively being worked to understand root cause and the below information is to keep the vehicle in
service until a corrective action can be implemented.
SYMPTOMS
Diagnostic Trouble Codes & Dashboard Indicator Lights:
DTC/Light Description
Auxiliary Cab Heater : Mechanical System
ISPN 5574 FMI 7 Not Responding Or Out Of Adjustment
Customer Observations or Concerns:
Amber Warning Lamp (AWL) - solid
Coolant leaking or 'overboiling' from the cabin heat surge tank overflow hose
SPECIAL TOOLS / SOFTWARE
Tool Description [Tool Number [Comments | Instructions |
N/A N/A N/A N/A
SERVICE PARTS INFORMATION
a ent Quantity
Kit Description Part Number Required Notes
N/A NIA N/A N/A
DIAGNOSTIC STEPS
IStep|Action
Decision
DIAGNOSTIC:
ls SPN 5574 FMI 7 active, with coolant coming out of the cabin heat surge tank
loverflow hose?
Yes. Proceed to step 2
No. If 5574 FMI 7 is set with no other
1 isymptoms or conditions, proceed with
IFCAP.
Step|Action Decision
2 |DIAGNOSTIC:
ls the driver input selection for heat temperature control in the colder position?
)Yes. Turn control to full hot position,
ithis allows the coolant flow valve to be|
icompletely open.
Run heater for 5 minutes and check
coolant level. Top off as needed
If vehicle operates normally, return
back to service and inform operator to
lleave temperature control in full hot
position at this time.
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TSB/Document ID: IK2300022
Replacement Service Bulletin Number:
MFR Communication Date: 2023-11-07
MFR Internal Campaign ID/Software Version:
Communication Type: Service Bulletin/Repair Instructions
NHTSA Components: VISIBILITY:DEFROSTER/DEFOGGER/HVAC SYSTEM
MFR Component System:
MFR Component Subsystem:
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