Engine Coolant Temperature Data Valid But Above Normal (Most Severe)
The VOLVO-MACK-MID128-PID110-FMI0 (Volvo/Mack D/MP Series) diesel fault code means: Engine Coolant Temperature Data Valid But Above Normal (Most Severe). This is a critical severity code.
- Keep driving?
- No -- stop driving
- DIY difficulty
- intermediate
- Estimated cost
- $300-$1,800
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Common Symptoms
- Temperature gauge at or above red line
- Engine forced shutdown or severe derate
- Coolant boiling from overflow tank
- Steam from engine bay
- Hot coolant smell in cab
Probable Causes (Ranked by Likelihood)
- Actual engine overheat — low coolant, failed fan, stuck thermostat Very Likely
- Plugged or dirty radiator/CAC restricting heat transfer Likely
- Viscous fan clutch or electric fan failure Likely
- Water pump failure or belt slippage Possible
- Failed ECT sensor reporting falsely high Less Likely
Step-by-Step Diagnostic Procedure
SHUT DOWN engine immediately when this fault is active; continuing to run risks head, piston, or bearing damage.
Verify coolant level after cooldown (never open a hot cap); top up with correct Volvo/Mack-spec ELC.
Inspect belt drive, viscous fan engagement on hot run, and radiator/CAC fins for debris blockage.
Connect Volvo PTT or Mack Guided Diagnostics and command fan ON to verify clutch engages.
Test thermostat opening temp in hot-water bath; replace if stuck closed.
Pressure-test cooling system for leaks; combustion-gas test coolant for head gasket leak.
Frequently Asked Questions
What does Volvo/Mack code MID128-PID110-FMI0 mean?
Volvo/Mack code MID128-PID110-FMI0 (Engine Coolant Temperature Data Valid But Above Normal (Most Severe)) is a critical-severity diagnostic trouble code set on D11/MP7, D13/MP8, and D16/MP10 diesel engines in Volvo VNL/VNR and Mack Anthem/Pinnacle/Granite/Titan trucks. It indicates a fault in the cooling system and should be read with Volvo Premium Tech Tool (PTT) or Mack Guided Diagnostics.
Can I drive a Volvo or Mack truck with code MID128-PID110-FMI0?
No — this fault typically triggers derate or forced engine shutdown countdown. Further operation risks engine damage or stranding. Repair before continuing service.
How much does it cost to fix Volvo/Mack code MID128-PID110-FMI0?
Typical repair falls in the range $300-$1,800. Sensor/wiring repairs are at the low end; EGR cooler, NOx sensor set, DEF pump, injector, or head work runs at the high end. Volvo PTT or Mack Guided Diagnostics is normally required for calibration and parameter programming.