Injector Cylinder 5 Circuit Current Below Normal / Open
The VOLVO-MACK-MID128-PID655-FMI5 (Volvo/Mack D/MP Series) diesel fault code means: Injector Cylinder 5 Circuit Current Below Normal / Open. This is a serious severity code.
Unverified. We could not confirm this code's definition against freely available manufacturer documentation, so treat the meaning, severity and fix guidance on this page as unconfirmed. Check it against the manufacturer's service information for your exact model and serial range before acting on it. This page is kept out of search engines for that reason, and we are working through this family manual by manual.
- Keep driving?
- Short distances only
- DIY difficulty
- advanced
- Estimated cost
- $600-$2,400
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View pilot availability →What Are the Symptoms of VOLVO-MACK-MID128-PID655-FMI5?
- Cylinder 5 misfire / rough idle
- White or black smoke at startup
- Power loss and reduced fuel economy
- Engine derate under load
- Check Engine Light illuminated
- Audible clatter or knock from affected bank
What Causes VOLVO-MACK-MID128-PID655-FMI5? (Most Likely First)
- Failed injector on cylinder 5 (electrical or mechanical) Very Likely
- Harness damage at valve-cover injector connector Likely
- Valve-cover injector pass-through seal leaking oil into connector Likely
- Leaking or stuck injector nozzle (balance failure) Possible
- ECM injector driver output fault Less Likely
Can I Still Drive with VOLVO-MACK-MID128-PID655-FMI5?
Short distances only. VOLVO-MACK-MID128-PID655-FMI5 is rated serious severity. Keep trips short and get it diagnosed soon rather than waiting for symptoms to worsen.
Frequently Asked Questions
What does Volvo/Mack code MID128-PID655-FMI5 mean?
Volvo/Mack code MID128-PID655-FMI5 (Injector Cylinder 5 Circuit Current Below Normal / Open) is a serious-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 fuel injector 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-PID655-FMI5?
Short distances may be acceptable to reach a repair facility, but the fault will escalate to derate (typically 55 mph then 5 mph on aftertreatment faults). Do not defer diagnosis beyond a shift.
How much does it cost to fix Volvo/Mack code MID128-PID655-FMI5?
Typical repair falls in the range $600-$2,400. 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.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose VOLVO-MACK-MID128-PID655-FMI5?
Connect Volvo PTT or Mack Guided Diagnostics and run cylinder cutout / balance test; confirm cylinder 5 is the offender.
Measure injector coil resistance at the valve-cover pass-through for cylinder 5 (spec per service manual).
Remove valve cover and inspect injector harness for chafe, oil contamination, or arcing.
Pull the injector and inspect nozzle for clogging, carbon, or cracked tip.
Run injector return-flow balance test — excess return on one cylinder indicates a leaking injector.
After injector replacement, program new injector trim codes via Volvo PTT or Mack Guided Diagnostics.
Sources 1
This page is built from documented references. Verify against your own service info before repair work.
- SAE J1939-73Application Layer: Diagnostics (defines the SPN/FMI fault-identifier framework)
Which Vehicles Commonly Get VOLVO-MACK-MID128-PID655-FMI5?
- Volvo VNL 760/860 with D13
- Volvo VNR 640 with D11/D13
- Mack Anthem with MP8
- Mack Pinnacle with MP7/MP8
- Mack Granite with MP7/MP8
- Mack Titan with MP10
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