Cummins Fault Code

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145 (SPN 110 FMI 3)

Engine fan runs 100%; Gauge pinned at zero/cold; Engine over-fuels on hot start (black smoke).

System

Not specified

Symptom

Engine fan runs 100%; Gauge pinned at zero/cold; Engine over-fuels on hot start (black smoke).

Diagnosis & fix steps

Engine Coolant Temp 1 - Voltage High. LOGIC: Signal > 4.5V (Open Circuit). The ECM sees infinite resistance, assumes the wire is cut, and defaults to -40°F for safety. ACTION: 1. Unplug sensor and Jumper pins A to B. If code changes to 144 (Voltage Low), harness is good. 2. Verify 5V ref at plug. 3. Check for pins "backed out" of the ECM connector. FIX: Replace Coolant Temp Sensor or repair broken signal/return wire.

Red Seal field insights

Most Cummins engines use the same sensor for Coolant and Intake Air temp. If you are in a pinch, you can swap them to see if the fault follows the sensor.

Same code keeps coming back?

That's a program problem, not a part problem. Book a 30-minute uptime review with Grant, a Red Seal Heavy Duty Technician.

Book an uptime review

Read before you touch anything

  • This is general reference information, not a repair manual. It is for trained, qualified technicians.
  • Fault codes, meanings and procedures vary by model, serial number and software version. Confirm the code and the procedure against the manufacturer's service manual before acting.
  • Follow the OEM service manual, torque specs and your site's safety procedures: lockout/tagout, block raised equipment, relieve hydraulic, fuel and air pressure, and let hot systems cool.
  • You use this information at your own risk. Adventure Mechanical and AM Fleet Integrity accept no liability for damage, injury, downtime or loss arising from its use.
  • Not affiliated with or endorsed by any manufacturer. Brand names are used only to identify the equipment a code applies to.

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