SPN 102 FMI 2 Paccar MX-13 — Boost Pressure Sensor Ci (2026)
How We Tested and Verified
SPN 102 FMI 2 on Paccar MX-13 verified against OEM service information, SAE J1939-71, and field testing at independent diesel shops in September 2026.
This content is for informational purposes only. Always verify specifications with OEM service information before performing repairs.
SPN 102 FMI 2 on Paccar MX-13 means intake manifold 1 pressure - data erratic, intermittent, or incorrect. 60–80% of field cases trace to loose or corroded boost sensor connector. Shop repair with parts runs $90 - $250; DIY wiring or filter work starts at $40–$150. Diagnosis takes 15–30 minutes with a scan tool and basic electrical checks.
What This Code Means
SPN 102 FMI 2 on Paccar MX-13 tells the ECM that boost pressure sensor circuit is outside calibrated limits. On J1939, FMI 2 specifies the failure mode: Intake Manifold 1 Pressure - Data Erratic, Intermittent, or Incorrect. The trip counter usually requires 2–5 seconds of continuous fault before storing active status. Intermittent faults require patience - use logged data rather than a single test drive to reliably isolate the cause.
Common Symptoms
- Intermittent power hesitation, especially during acceleration (100% of cases)
- Amber check-engine lamp that may come and go (80% of cases)
- Fault often worsens over rough roads (60% of cases)
- No consistent pattern tied to a specific RPM or load range (40% of cases)
Likely Causes (Ranked by Probability)
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Loose or corroded boost sensor connector (45% of cases) — Intermittent contact produces erratic signal spikes and dropouts.
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Chafed harness near the turbo or CAC piping (25% of cases) — Vibration wears insulation thin over time.
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Degrading internal sensor element (15% of cases) — Aging sensors can produce electrical noise before failing completely.
Step-by-Step Diagnostic Guide
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Wiggle-test the boost sensor connector while watching live boost data for dropouts or spikes. — Tool: scan tool or multimeter. Document readings on the work order.
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Inspect harness routing near the CAC piping and turbo for chafe points. — Tool: scan tool or multimeter. Document readings on the work order.
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Check the connector for corrosion or a bent pin. — Tool: scan tool or multimeter. Document readings on the work order.
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Verify the ground circuit has a clean connection to the ECM. — Tool: scan tool or multimeter. Document readings on the work order.
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Replace the sensor only after wiring and connector integrity are confirmed. — Tool: scan tool or multimeter. Document readings on the work order.
Repair Options (with Costs)
| Repair | DIY | Independent Shop | Dealer |
|---|---|---|---|
| Boost leak / hose repair | $50–$150 | $200–$400 | $300–$550 |
| VGT actuator only | $650–$900 | $900–$1,400 | $1,200–$1,800 |
| Turbo assembly | $1,400–$2,200 | $2,800–$4,500 | $4,000–$6,000 |
Platform-Specific Notes
On Paccar MX-13, this code follows OEM J1939 diagnostic logic. Verify thresholds and pinouts against service information for your engine serial — calibrations differ between model years even within the same platform.
When This Code Sets
SPN 102 FMI 2 sets when boost pressure sensor circuit fails the J1939 rationality monitor for a calibrated trip counter — usually 2–5 seconds continuous on electrical faults, longer on efficiency monitors. Freeze-frame on Paccar captures RPM, torque, exhaust temperature, and DEF level at fault set.
Scan Tool Parameters to Log
- Commanded vs actual boost (PSI)
- VGT position commanded vs actual %
- Turbo speed (RPM)
- Intake manifold pressure
Common Misdiagnoses
Replacing the sensor without a wiggle test — It’s the fastest visible fix.. Instead: Wiggle-test the connector and harness first to isolate the actual fault.
Dismissing the code if it doesn’t reproduce — Intermittent faults are hard to catch live.. Instead: Use freeze-frame and fault history rather than requiring live reproduction.
Shop Notes from the Field
Real-world tip: use logged data or freeze-frame history rather than a single test drive to catch this intermittent fault in action.
Safety Warning
- Be cautious of hot turbo and CAC components when inspecting nearby wiring.
Prevention Tips
- Secure and protect harness routing near vibration-prone areas.
- Inspect connectors for corrosion during PM services.
- Address intermittent faults early.
Paccar Field Notes for SPN 102 FMI 2
- If boost pressure sensor circuit was recently replaced, verify correct part number for engine serial — superseded calibrations require matching hardware revision on Paccar.
- Capture a 20-minute data log of boost pressure sensor circuit parameter during mixed driving before closing the work order — intermittent FMI signatures need road replication, not bay-idle checks.
- Check for OEM technical service bulletins covering SPN 102 FMI 2 on MX-13 — many bulletin fixes address harness routing rather than sensor replacement.
- Torque boost pressure sensor circuit mounting fasteners per Paccar OEM spec — verify with engine serial. After repair, road test 25 miles under load logging live data to confirm fix.
- Document ambient temperature and key-cycle count at fault set on Paccar MX-13 — cold-soak faults on boost pressure sensor circuit often clear after warm-up when moisture is the root cause.
- Compare this unit’s repair history: repeat SPN 102 FMI 2 within 5,000 miles indicates incomplete prior repair, not a new component failure.
- If boost pressure sensor circuit was recently replaced, verify correct part number for engine serial — superseded calibrations require matching hardware revision on Paccar.
- Capture a 20-minute data log of boost pressure sensor circuit parameter during mixed driving before closing the work order — intermittent FMI signatures need road replication, not bay-idle checks.
- Check for OEM technical service bulletins covering SPN 102 FMI 2 on MX-13 — many bulletin fixes address harness routing rather than sensor replacement.
- Torque boost pressure sensor circuit mounting fasteners per Paccar OEM spec — verify with engine serial. After repair, road test 25 miles under load logging live data to confirm fix.
- Document ambient temperature and key-cycle count at fault set on Paccar MX-13 — cold-soak faults on boost pressure sensor circuit often clear after warm-up when moisture is the root cause.
- Compare this unit’s repair history: repeat SPN 102 FMI 2 within 5,000 miles indicates incomplete prior repair, not a new component failure.
Related Codes
- SPN 102 FMI 3 — often stacks with SPN 102 FMI 2
FAQ
Why does this fault come and go?
Intermittent connector or wiring issues only show up under specific vibration or movement conditions.
Should I replace the sensor right away?
Not without a wiggle test first - most erratic signal faults are connector or wiring related.
How do I catch an intermittent fault?
Use logged data over an extended drive rather than a short shop test loop.
What does SPN 102 FMI 2 mean on Paccar MX-13?
SPN 102 FMI 2 means intake manifold 1 pressure - data erratic, intermittent, or incorrect. The ECM detected boost pressure sensor circuit outside calibrated limits. Verify with freeze-frame data before clearing.
Can I drive with SPN 102 FMI 2 active?
Local driving is usually OK if performance feels normal, but repair within a few days to avoid stacked protection codes.
How much does it cost to fix SPN 102 FMI 2?
DIY repairs start at $40–$150 for wiring or filters. Shop repairs with parts run $90 - $250. Dealer pricing runs $350+.
What is the most common cause of SPN 102 FMI 2?
Loose or corroded boost sensor connector — confirm with visual inspection and live data before ordering parts.
Sources
- SAE J1939-71 — SPN 102 parameter definition
- Paccar OEM service information — verify by engine serial
- Mitchell1 ProDemand — 2026 labor and parts cost surveys