International Fault Code SPN 3605 FMI 4: Engine Coolant Pump Control: Voltage Below Normal, Or Shorted To Low Source

Code details

Manufacturer

International (Navistar)

Applies to

International A26 (2024–2025)

Fault code

SPN 3605 FMI 4

J1939 SPN

3605

FMI

4 — Voltage below normal, or shorted to low source

Truck models in source

3200, 4100, 4300, 4400, 7300, 7400, 7500, 7600, 7700, 8500, 8600, BE 200, CE Bus, CXT, DuraStar, LoneStar, MXT, ProStar, RXT, TranStar, WorkStar

What to do next

• Read active and inactive codes with the OEM service tool (Diamond Logic Builder can clear previously active codes) and note the occurrence count.
• FMI 4 tells the shop the type of failure to test for: voltage below normal, or shorted to low source.
• Have a heavy-duty diesel technician confirm the fault against the engine or chassis service manual before replacing parts.

Related fault codes

• International Fault Code SPN 3605 FMI 3 — Engine Coolant Pump Control: Voltage Above Normal, Or Shorted To High Source
• International Fault Code SPN 3605 FMI 5 — Engine Coolant Pump Control: Current Below Normal Or Open Circuit
• PACCAR Fault Code P2600 — Coolant Pump – Open Circuit on ECU (D420) Pin (C1)
• PACCAR Fault Code P2604 — Coolant Pump – Voltage Too High or Short Circuit to Supply on ECU (D420) Pin (C1)
• PACCAR Fault Code P2605 — Coolant Pump – Voltage Too Low or Short Circuit to Ground on ECU (D420) Pin (C1)
• PACCAR Fault Code P2603 — Coolant Pump Speed – Data Valid But Too High