Cummins
Cummins fault code
SPN 191 / FMI 18
Cummins Fault Code 489: Transmission Output Shaft (Tailshaft) Speed Low – Warning
489 on Cummins engines means: Transmission Output Shaft (Tailshaft) Speed Low – Warning. The failure mode (FMI 18) is “data valid but below normal range (moderately severe)”.
Lamp: Yellow
Engine may continue to run, but must be repaired the same day.
Code details
- Manufacturer
- Cummins
- Applies to
- Cummins QS-series electronic engines
- Fault code
- 489
- J1939 SPN
- 191
- FMI
- 18 — Data valid but below normal range (moderately severe)
- J1587 PID / SID
- P191
- Engine models
- QSB, QSC, QSL9, QSM11, QSX15
What to do next
- Read active and inactive codes with the OEM service tool and note the occurrence count.
- FMI 18 tells the shop the type of failure to test for: data valid but below normal range (moderately severe).
- Have a heavy-duty diesel technician confirm the fault against the engine or chassis service manual before replacing parts.
Get this code diagnosed
Send one request and nearby diesel shops and mobile mechanics can quote the repair.
Owner-OperatorAdd this truck & start trial
Run your own truck?
Log maintenance, track fault codes, and get roadside breakdown dispatch.
$39.99/mo
Cancel anytime
More ways Repairius keeps vehicles running
Tools for owner-operators, shops, fleets and drivers — all in one place.
Auto & Truck Shop OS
From $99.99/mo- Work orders & job management
- Digital vehicle inspections
- Parts lookup & inventory
- Estimates, invoices & payments
Fleet Maintenance
From $129/mo- Preventive maintenance schedules
- Driver DVIRs & defect reports
- Safety & compliance clearance
- Preferred shop dispatch & approvals
My Garage
100% free- Digital glovebox for your vehicles
- Maintenance history & reminders
- Recall alerts
- Book verified local shops
Owner-Operator? Track this truck for $39.99/mo
StartFix these trucks? Get your shop listed free·Find a diesel shop
Related fault codes
- Cummins Fault Code 489 — Transmission Output Shaft (Aux Gov) Speed Low – Warning
- Cummins Fault Code 349 — Transmission Output Shaft (Tailshaft) Speed High – Warning
- Cummins Fault Code 349 — Transmission Output Shaft (Tailshaft) Speed High – Warning
- PACCAR Fault Code U1548 — CAN Communication – Message (ETC1) Out of Range, Transmission Output Shaft Speed From Transmission System
- International Fault Code SPN 191 FMI 14 — TOSS / VSS Error – Invalid Signal
- International Fault Code SPN 191 FMI 3 — TOSS / VSS Signal – Out of Range HIGH
- International Fault Code SPN 191 FMI 4 — TOSS / VSS Signal – Out of Range LOW
- International Fault Code SPN 191 FMI 5 — TOSS / VSS Open Circuit Fault
Source: Cummins "Diagnostic Fault Codes For Cummins Engines", publication 80-1044 Rev 5/2013, page 15. See also OBD-II codes.