EGR Valve Position Sensor Voltage Above Normal
The VOLVO-MACK-MID128-PID2791-FMI3 (Volvo/Mack D/MP Series) diesel fault code means: EGR Valve Position Sensor Voltage Above Normal. This is a moderate severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- intermediate
- Estimated cost
- $600-$3,200
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Common Symptoms
- Power loss under load
- Black smoke under acceleration
- Higher than normal EGT readings
- Failed or incomplete regen cycles
- Check Engine Light and possible derate
Probable Causes (Ranked by Likelihood)
- EGR valve carbon-seized in partially open position (common on MP7/MP8) Very Likely
- Failed EGR position sensor Likely
- Clogged EGR cooler restricting flow Likely
- Wiring harness damage at EGR valve connector Possible
- Leaking EGR cooler causing coolant loss (see PID 110 FMI 16) Possible
Step-by-Step Diagnostic Procedure
Connect Volvo PTT or Mack Guided Diagnostics and confirm MID128-PID2791-FMI3 active; read EGR position commanded vs actual.
Command EGR valve full sweep; failure to reach commanded position indicates carbon lockup or actuator fault.
Remove EGR valve and inspect flow path; soak in carbon cleaner and reinstall if only mildly fouled.
Measure EGR position sensor supply voltage and signal at the ECM connector.
Pressure-test EGR cooler for internal coolant leak (this is a D13/MP8 high-mileage failure).
Inspect harness routing near turbo for chafe or heat damage; replace damaged pins or connectors.
Frequently Asked Questions
What does Volvo/Mack code MID128-PID2791-FMI3 mean?
Volvo/Mack code MID128-PID2791-FMI3 (EGR Valve Position Sensor Voltage Above Normal) is a moderate-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 EGR valve position sensor 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-PID2791-FMI3?
Limited short-term operation is usually possible, but the fault will illuminate the Check Engine Light and should be diagnosed promptly to avoid cascading aftertreatment or fueling faults.
How much does it cost to fix Volvo/Mack code MID128-PID2791-FMI3?
Typical repair falls in the range $600-$3,200. 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.
Sources
This page is built from documented references. Verify against your own service info before repair work.