MID 128 PID 105 FMI 0: Intake Manifold Temperature - Too High (Volvo)

MID 128 PID 105 FMI 0 - Intake Manifold Temperature Too High

**Why This Matters**: High intake air temperature reduces air density, which means less oxygen for combustion. The ECM responds by reducing fuel (derate) to protect the engine from detonation and excessive exhaust temperatures.

🔥 What Causes High Intake Temps

**#1 - EGR System Issues**

The EGR system recirculates hot exhaust gas into the intake. If the EGR cooler is clogged or inefficient, or if the EGR valve is stuck open, too much hot gas enters the intake [citation:4].

**#2 - Charge Air Cooler Problems**

The intercooler (CAC) should drop charge air temperature significantly after the turbo. If the CAC is externally blocked (bugs, mud, debris) or internally restricted, cooling efficiency drops.

**#3 - Overboost Condition**

Higher boost pressure generates more heat. If the turbo is overboosting (see PID 102 FMI 0), intake temps will rise accordingly.

🛠️ Diagnostic Approach

**Check for Simple Stuff First:**

• Look for debris blocking the charge air cooler fins
• Check for bent/crushed charge air pipes
• Verify fan operation (if electric, ensure it's running)

**Monitor with Scan Tool:**

• Compare intake manifold temperature to ambient temperature
• At cruise, IAT should be within 20-40°F of ambient + heat from compression
• Under heavy load, temps rise but should stabilize

**EGR-Specific Checks:**

• Monitor EGR valve position
• Check EGR cooler for leaks (coolant in exhaust)
• Inspect EGR differential pressure sensor (PID 411)

📸 Image Ideas

• "Charge air cooler blocked with debris" (search "radiator blockage")
• "EGR cooler soot buildup" (common diesel repair images)

💡 Prevention Tips

After 500,000 miles, consider:

• Removing and cleaning the EGR cooler [citation:4]
• Cleaning the charge air cooler fins
• Checking turbocharger performance

*"EGR coolers on D13s clog up over time. If you're getting high intake temp codes, it's often the cooler partially blocked, not the sensor."* — Volvo technician