Cummins Fault Code
Free · no signup145 (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.
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