Universal HD Fault Code
Free · no signupSPN 105 FMI 03
White Smoke Cold / Harsh Cold Engine Clatter
System
Air Intake
Symptom
White Smoke Cold / Harsh Cold Engine Clatter
Diagnosis & fix steps
LOGIC: Intake Manifold Air Temperature Sensor Circuit Voltage High.
ACTION: Disconnect combined MAP/MAT sensor. Measure sensor circuit voltage (5V pull-up on signal line). Test thermistor resistance across temperature pins (spec: ~2.5kΩ at 20°C). Inspect harness for broken conductors or backed-out connector pins.
Red Seal field insights
Open Circuit Default: An open circuit drops signal voltage to the 5V ceiling, which the ECM interprets as extreme sub-zero intake air (-40°C). The computer advances base injection timing and maximizes pre-heat grids, causing cold clatter.
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.
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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