What does Cummins fault code 153 (SPN 105 FMI 3) mean?

Q: What does Cummins fault code 153 (SPN 105 FMI 3) mean?

153 (SPN 105 FMI 3) indicates: High idle; Excessive black smoke; Cooling fan locked on 100%. Fix: Intake Manifold Air Temp - Voltage High. LOGIC: Signal > 4.5V (Open Circuit). The ECM assumes -40°F air temp and over-fuels to compensate for "cold" air density. ACTION: 1. Locate sensor on the intake horn. 2. Jumper pins to check for FMI 4. 3. Check for soot/oil buildup on sensor tip. FIX: Replace Intake Air Temp Sensor or repair broken wiring.

Cummins Fault Code

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153 (SPN 105 FMI 3)

High idle; Excessive black smoke; Cooling fan locked on 100%.

System

Not specified

Symptom

High idle; Excessive black smoke; Cooling fan locked on 100%.

Diagnosis & fix steps

Intake Manifold Air Temp - Voltage High. LOGIC: Signal > 4.5V (Open Circuit). The ECM assumes -40°F air temp and over-fuels to compensate for "cold" air density. ACTION: 1. Locate sensor on the intake horn. 2. Jumper pins to check for FMI 4. 3. Check for soot/oil buildup on sensor tip. FIX: Replace Intake Air Temp Sensor or repair broken wiring.

Red Seal field insights

If your fan won't stop screaming, this is your #1 suspect. The ECM defaults the fan to "On" whenever it loses the intake temperature signal.

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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