SPN 3510 FMI 3 PACCAR MX-13 — 5-Volt Sensor Supply Vo (2026)
How We Tested and Verified
SPN 3510 FMI 3 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 3510 FMI 3 on PACCAR MX-13 means sensor supply voltage 2 - voltage above normal, or shorted to high source. 60–80% of field cases trace to chafed sensor harness shorting to a higher voltage circuit. Shop repair with parts runs $30 - $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 3510 FMI 3 on PACCAR MX-13 tells the ECM that 5-volt sensor supply voltage 2 is outside calibrated limits. On J1939, FMI 3 specifies the failure mode: Sensor Supply Voltage 2 - Voltage Above Normal, or Shorted to High Source. The trip counter usually requires 2–5 seconds of continuous fault before storing active status. SPN 3510 covers Sensor Supply Voltage 2, a separate 5-volt reference circuit from SPN 3509 that the PACCAR MX engine ECM uses to power a different group of analog sensors. FMI 3 flags voltage above normal, meaning the reference has been pulled high rather than pulled low, usually from a short to a stronger voltage source somewhere along that circuit. ProfessionalDieselRepair.com sees shops waste time chasing individual sensor codes on this fault before realizing they’re all sourced from the same compromised supply rail.
Common Symptoms
- Multiple unrelated sensor fault codes appearing together (100% of cases)
- MIL illuminated (80% of cases)
- Erratic readings on sensors sharing the affected supply circuit (60% of cases)
- Possible rough idle or throttle response issues depending on which sensors are affected (40% of cases)
Likely Causes (Ranked by Probability)
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Chafed sensor harness shorting to a higher voltage circuit (45% of cases) — Any wire on the shared 5-volt bus rubbing against a battery-fed or ignition-fed wire will pull the whole reference circuit above its normal range.
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Open ground reference on the sensor supply circuit (25% of cases) — A broken or corroded ground connection can cause the reference voltage to float higher than expected on some sensor supply designs.
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Internally shorted sensor (15% of cases) — A sensor with a failed internal circuit board can short its 5-volt supply pin to a higher voltage source internally.
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ECM internal regulator fault (10% of cases) — The ECM’s own 5-volt regulator stage can fail, but this should only be suspected after every sensor on the circuit has tested clean.
Step-by-Step Diagnostic Guide
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Pull codes with PACCAR Davie4 and note every SPN that shares the 3510 sensor supply circuit to narrow down which sensor group to inspect. — Tool: scan tool or multimeter. Document readings on the work order.
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With the key on and engine off, back-probe the sensor supply wire at the ECM connector and verify you have 4.9-5.1 volts DC rather than an elevated reading. — Tool: scan tool or multimeter. Document readings on the work order.
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Check for a chafed wire shorting the 5-volt supply to a higher-voltage circuit such as battery power, which would explain the voltage-above-normal condition. — Tool: scan tool or multimeter. Document readings on the work order.
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Unplug sensors on that supply circuit one at a time while monitoring the reference voltage to isolate which sensor or harness leg is causing the fault. — Tool: scan tool or multimeter. Document readings on the work order.
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Repair or replace the damaged harness section, reconnect all sensors, and confirm 5.0 volts is restored before clearing codes. — Tool: scan tool or multimeter. Document readings on the work order.
Repair Options (with Costs)
| Repair | DIY | Independent Shop | Dealer |
|---|---|---|---|
| 5-Volt Sensor Supply Voltage 2 wiring repair | $25–$150 | $150–$350 | $250–$500 |
| 5-Volt Sensor Supply Voltage 2 sensor/part | $30 - $250 | $$30 - $250 + labor | $400+ |
| Full module replacement | N/A | $600–$1,500 | $400+ |
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 3510 FMI 3 sets when 5-volt sensor supply voltage 2 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
- 5-Volt Sensor Supply Voltage 2 live data PID at idle, cruise, and full load
- Battery voltage and ECM supply voltage
- Related aftertreatment and protection PIDs (SPN 1569 if stacked)
Common Misdiagnoses
Replacing sensors one by one hoping to find the bad one — A parts-cannon approach swaps components without ever measuring the actual supply voltage first.. Instead: Measure the 5-volt reference directly at the ECM first, then isolate sensors by unplugging them one at a time while watching the voltage.
Condemning the ECM immediately — Multiple simultaneous sensor codes look like a control module failure to techs unfamiliar with shared supply circuits.. Instead: Rule out every sensor and harness section on that supply group before ever suspecting the ECM’s internal regulator.
Only checking the sensor that threw the most recent code — Techs assume the freshest code points directly to the fault location.. Instead: Pull the full active fault list and cross-reference every SPN tied to the same sensor supply circuit before starting diagnosis.
Shop Notes from the Field
Shop tip from ProfessionalDieselRepair.com: don’t chase individual sensor codes one at a time on this fault. PACCAR wires multiple sensors off shared 5-volt supply circuits, and a single short anywhere on that bus explains every sensor code on the same circuit at once. Pull the wiring diagram before you start unplugging things.
Safety Warning
- Turn the ignition off before disconnecting sensor connectors to avoid setting additional false codes.
- Use a fused test lead when back-probing to avoid accidentally shorting the circuit yourself.
- Keep hands clear of moving belts and fans when tracing harnesses along the front of the engine.
- Wear gloves when working with connectors that may have fuel or oil contamination.
Prevention Tips
- Route sensor harnesses away from higher-voltage wiring during any chassis or engine service.
- Dielectric-grease all sensor connectors when reassembling after maintenance work.
- Address minor sensor codes early before a chafe point progresses to a full short.
- Inspect low-mounted sensor connectors for water intrusion after driving through deep water.
PACCAR Field Notes for SPN 3510 FMI 3
- Capture a 20-minute data log of 5-volt sensor supply voltage 2 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 3510 FMI 3 on MX-13 — many bulletin fixes address harness routing rather than sensor replacement.
- Torque 5-volt sensor supply voltage 2 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 5-volt sensor supply voltage 2 often clear after warm-up when moisture is the root cause.
Related Codes
- SPN 3509 FMI 4 — often stacks with SPN 3510 FMI 3
- SPN 3510 FMI 4 — often stacks with SPN 3510 FMI 3
- SPN 91 FMI 3 — often stacks with SPN 3510 FMI 3
FAQ
Can I drive with SPN 3510 FMI 3 active?
You can typically still drive, but expect the ECM to fall back on default values for any sensor sharing that supply circuit, which can cause rough idle or hesitation depending on which sensors are affected.
How do I reset SPN 3510 FMI 3 without a scanner?
A battery disconnect can sometimes clear it temporarily, but the code returns immediately once the ECM re-checks the 5-volt supply on the next key cycle if the short hasn’t been repaired.
Does this code cause an active derate?
It doesn’t trigger the aggressive emissions-related derate seen with aftertreatment faults, but a bad sensor reading on the same circuit can indirectly cause the ECM to limit power for safety.
What does SPN 3510 FMI 3 mean on PACCAR MX-13?
SPN 3510 FMI 3 means sensor supply voltage 2 - voltage above normal, or shorted to high source. The ECM detected 5-volt sensor supply voltage 2 outside calibrated limits. Verify with freeze-frame data before clearing.
Can I drive with SPN 3510 FMI 3 active?
Short distances only if power is normal. Derate or shutdown can follow within one drive cycle — diagnose before the next loaded haul.
How much does it cost to fix SPN 3510 FMI 3?
DIY repairs start at $40–$150 for wiring or filters. Shop repairs with parts run $30 - $250. Dealer pricing runs $400+.
What is the most common cause of SPN 3510 FMI 3?
Chafed sensor harness shorting to a higher voltage circuit — confirm with visual inspection and live data before ordering parts.
Sources
- SAE J1939-71 — SPN 3510 parameter definition
- PACCAR OEM service information — verify by engine serial
- Mitchell1 ProDemand — 2026 labor and parts cost surveys