PACCAR MID 128 PID 105 FMI 10: Meaning, Causes & Fix
Intake Manifold Temperature — abnormal rate of change detected
Reviewed by Diesel Mechanic Writers · Last updated August 04, 2026
Quick Answer
MID 128 PID 105 FMI 10 = Intake Manifold Temperature
Severity: 🟠 CHECK SOON · System: Intake Manifold Temperature Sensor · ✅ Can continue with caution
Diagnostic Reference
| Field | Details |
|---|---|
| Code | MID 128 PID 105 FMI 10 |
| Protocol | J1587 MID: 128 PID: 105 |
| Component | Intake Manifold Temperature Sensor |
| Manufacturer | PACCAR |
| Engine Series | MX-13 |
| Severity | 🟠 CHECK SOON |
| SAE Reference | SAE J1587/J1708 — MID 128, PID 105 |
Possible Causes
- Sensor response time degraded from soot/oil coating on probe tip
- Intermittent open circuit in sensor wiring from vibration
- Charge air cooler heat soak after prolonged idle
- Sensor reading wrong due to incorrect ECM calibration
- Aftermarket intake modification affecting sensor airflow
Top Causes Ranked by Frequency
- Corroded or loose sensor connector pins (35% of sensor/electrical faults)
- Wiring harness chafing causing intermittent open or short circuits (25%)
- Failed sensor providing out-of-range signal to ECM (20%)
- ECM 5V reference circuit overload from multiple sensor failures (10%)
- CAN bus communication fault from terminating resistor or module failure (10%)
In-Depth Diagnostic Procedure
Follow these diagnostic steps to identify the root cause of MID 128 PID 105 FMI 10 on your PACCAR MX-13. A J1939-compatible diagnostic scan tool is recommended.
- Connect scan tool and retrieve all active and inactive fault codes, noting which modules are reporting communication errors
- Check battery voltage and ground connections — low system voltage (below 11V) or poor grounds cause erratic sensor readings and communication faults
- Backprobe the suspect sensor connector and measure reference voltage (typically 5V), signal voltage, and ground with a digital multimeter — compare readings to OEM specifications
- Inspect wiring harness for chafing, especially at common failure points: engine pass-through connectors, valve cover gasket connectors, and frame rail routing near sharp edges
- Perform wiggle test on the harness while monitoring live data — intermittent connections will cause sensor readings to spike or drop when the harness is moved
- If CAN bus faults are present, check terminating resistors (should measure 60 ohms across CAN high and CAN low with the key off and batteries disconnected)
Repair & Cost Estimate
| Item | Cost Range |
|---|---|
| Parts | $80 – $600 |
| Labor | 1–4 hours @ ~$150/hr = $150 – $600 |
| Estimated Total | $230 – $1,200 |
Sensor or connector replacement. Prices vary by location and dealer.
Frequently Asked Questions — Intake Manifold Temperature Sensor
How do I know if a sensor is bad or if the wiring is the problem?
Backprobe the sensor connector and measure reference voltage, signal, and ground. If the 5V reference is present and ground is good, but the signal is out of range, the sensor is likely bad. If reference voltage is missing or unstable, the problem is in the wiring or ECM. A wiggle test on the harness while monitoring live data will reveal intermittent connections.
Can I drive with a faulty sensor?
It depends on the sensor. Non-critical sensors (barometric pressure, fuel temperature) typically trigger CHECK SOON codes and the engine runs on a default value. Critical sensors (accelerator pedal, crankshaft position) can cause stalling or no-start conditions. If the engine runs normally despite the code, you can usually drive to a repair facility, but do not ignore the code indefinitely.
What causes CAN bus communication faults?
CAN bus faults are caused by wiring damage (chafed or cut wires), corroded connectors, failed terminating resistors, or a faulty module that corrupts bus communication. Heavy-duty trucks use J1939 CAN which requires 120-ohm terminating resistors at each end of the bus. Measuring 60 ohms across CAN high and CAN low (with power off) confirms the bus is intact.
How much does an ECM replacement cost?
A new ECM for a heavy-duty diesel engine costs $1,500–$4,000 for the part alone, plus 3–6 hours of labor for installation, programming, and parameter setup. Remanufactured ECMs are available for $800–$2,000. Always verify the ECM is truly faulty before replacing — many ECM codes are caused by wiring or sensor issues, not the ECM itself.
Why do sensor faults seem to happen more in wet weather?
Moisture ingress into sensor connectors causes corrosion and intermittent electrical contact. This is especially common at the engine harness pass-through connector (where wires enter the valve cover) and at under-hood sensor connectors that are not properly sealed. Dielectric grease on connector pins and OEM-rated weatherpack connectors help prevent moisture-related faults.
Diagnostic & Repair Procedure
- Step 1: Remove intake manifold temp sensor and clean probe tip with brake cleaner and soft brush
- Step 2: Graph temperature reading during warm-up with scan tool — should rise smoothly without jumps
- Step 3: Check wiring connector for loose terminals
- Step 4: Verify ECM calibration is latest available
- Step 5: Allow 2-minute cooldown after hot shutdown before recheck
Frequently Asked Questions
Is this a false alarm or a real problem?
CHECK SOON codes are rarely false alarms. The ECM has detected a parameter outside normal operating range. Sensor malfunctions can sometimes trigger false readings, but the majority of CHECK SOON codes indicate a developing issue that will worsen if left unaddressed. Use a diagnostic scan tool to verify sensor readings before replacing expensive parts.
Can I diagnose this without a scan tool?
Basic visual inspection can be performed without a scan tool — check wiring harnesses for chafing, connectors for corrosion, and related components for physical damage. However, to verify the fault, view live sensor data, and confirm the repair, a heavy-duty diagnostic scan tool (or a compatible OBD-II adapter with J1939/J1708 support) is strongly recommended for accurate diagnosis.
How soon should I schedule service?
Schedule service within the next 1–3 operating days. While the vehicle can continue operating normally, delaying repair increases the risk of the fault escalating to CHECK NEXT STOP severity. Additionally, some CHECK SOON conditions are precursors to emissions system faults that will trigger a mandatory derate if not addressed in a timely manner.
Estimated Repair Cost
Typical repair: $100–800 (Parts: $50–500 + Labor: 1–3 hours) · Costs vary by make/model and location
Related Fault Codes — MX-13
SPN 1077 FMI 14
🔴 STOP ENGINE
SPN 1347 FMI 7
🔴 STOP ENGINE
SPN 647 FMI 4
SPN 91 FMI 16
MID 130 PID 52 FMI 5
SPN 411 FMI 16
🟠 CHECK SOON
Related Codes Across Systems
Codes from the same SPN range, manufacturer, or system that may also be relevant:
SPN 520210 FMI 31
🔴 STOP ENGINE
SPN 524265 FMI 7
SPN 111 FMI 18
🔴 STOP ENGINE
SPN 110 FMI 15
🔴 STOP ENGINE
MID 128 PID 111 FMI 4
🟠 CHECK SOON
SPN 174 FMI 0
Associated Symptoms
References & Further Reading
- SAE J1939-73: Application Layer — Diagnostics. SAE International. Defines SPN N/A / FMI N/A fault code semantics for heavy-duty CAN networks. SAE J1939 Standard
- SAE J1587: Electronic Data Interchange Between Microcomputer Systems in Heavy-Duty Vehicle Applications. SAE International. Defines MID 128 parameter identification protocol. SAE J1587 Standard
- PACCAR MX-13 Service Manual: OEM diagnostic procedures for Intake Manifold Temperature Sensor faults. Consult the official PACCAR service documentation for your specific engine serial number.
- TMC RP 1210: Recommended Practice for Windows-Based Vehicle Diagnostic Interface. Technology & Maintenance Council (TMC) of American Trucking Associations.