SPN 1633 FMI 5Chassis
Cruise Control Resume Switch - Current Below Normal
Scan Tool — in guided session
DVOM Testing — in guided session
Connector Pinout — in guided session
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Overview
Fault Code
SPN 1633 / FMI 5
Category
Chassis
Derate Risk
No
Regen Inhibit
No
Inducement Risk
No
Component Location: Cruise control resume switch is typically located on the steering column stalk or dash-mounted switch panel.
Common Symptoms
- Cruise control resume function inoperative
- Cruise control will not resume to set speed
- Cruise control dash indicator illuminated or flashing
- Intermittent cruise control operation
Root Causes
- Open circuit in cruise control resume switch wiring Faulty cruise control resume switch Damaged wiring harness or connector to resume switch Corroded or loose switch connector pins Failed cruise control module
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Derate Behavior
Power Derate
No
System Interactions
SPN 1633 FMI 5 interacts with the following systems and may trigger cascading faults if not resolved promptly.
Common Diagnostic Mistakes
Replacing the sensor without verifying wiring continuity and supply voltage first.
Clearing codes without identifying and resolving the root cause — the fault will return.
Ignoring related active faults — cascading faults often share a root cause.
Skipping the connector inspection — corrosion and damaged pins are a leading cause of sensor faults.
Condemning the ECM before exhausting all wiring and component tests.
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OEM System Resources
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Related Diagnostic Articles
Deep-dive diagnostic page: SPN 1633 FMI 5 — Full FSM Sequence & Repair Steps — includes wiring notes, sensor specs, and gated repair procedures.
Authority References
Diagnostic procedures on this page are informed by OEM service literature and industry standards.
Cummins QuickServe OnlineOfficial Cummins service manuals, fault code lookup, and TSB database.Detroit Diesel DiagnoCentralDetroit Diesel diagnostic procedures, DDDL documentation, and service literature.PACCAR MX Engine ServicePACCAR MX-11 and MX-13 engine service documentation and DAVIE diagnostic guides.Volvo/Mack Tech ToolVolvo and Mack engine fault code reference and PTT/Tech Tool diagnostic procedures.ASE — Diesel Truck Technician CertificationNational Institute for Automotive Service Excellence — T2 Diesel Engines certification standards.EPA Aftertreatment & Emissions GuidelinesU.S. EPA heavy-duty diesel aftertreatment compliance, DPF/SCR regulations, and NOx standards.
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