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SPN 105 — Intake manifold air temperature

Safe to driveEnough to reach the yard

Updated: 2026-11-14

J1939 code SPN 105. Below — how the fault is worded at the factory by Cummins ISB, DAF, Dongfeng, Isuzu, KAMAZ, KAMAZ-5490, MAZ, Renault Trucks, SITRAK, YaMZ and ZF AS-Tronic, and what the second half of the code (FMI) means in the standard.

How to check it yourself

The intake manifold air temperature sensor, after the turbo and the intercooler. It is often one body with the boost sensor (SPN 102): four wires — 5 V, ground, pressure, temperature. The ECU uses it to protect the engine from hot air and to calculate the fuel quantity.

What it should read

Resistance of a typical NTC sensor at 20 °Cabout 2…3 kΩ
The same at 80 °Cabout 300 Ω — more precisely per the factory table
Voltage at the harness connector with the sensor unpluggedabout 5 V
Air after the intercooler under loadusually not above 50…60 °C

Check order

  1. FMI 0, 15, 16 (hot air): the intercooler is clogged with insects and dirt on the outside — wash it. Check the intercooler hoses and clamps: a crack also causes a loss of boost.
  2. FMI 3, 4: unplug the connector and measure the sensor resistance. An open sensor or wire is seen by the ECU as −40 °C frost (voltage high, FMI 3), a short as severe overheating (FMI 4). With the connector unplugged, the harness contacts should show about 5 V.
  3. Compare the diagnostics reading on a cold engine that has stood overnight with other temperatures: air, oil, coolant. All should be close to the outside temperature; one lagging 10 °C or more is suspect.
  4. If the sensor is combined with the boost sensor and SPN 102 is also present — check the connector and the shared 5 V supply, not each sensor separately.

Common causes — from most to least frequent

  1. Intercooler dirty on the outside.
  2. Corroded connector: the sensor sits low on the manifold, where water gets in.
  3. The sensor itself — an oil film from the turbo on the sensing element.
  4. Chafed wires at the manifold.

Cummins ISBDAFDongfengIsuzuKAMAZKAMAZ-5490MAZRenault TrucksSITRAKYaMZZF AS-Tronic

Cummins ISB 6.7 engine

FMI 0Intake manifold 1 temperature high, most severe
FMI 2Intake manifold 1 temperature signal erratic or incorrect
FMI 3Intake manifold 1 temperature sensor circuit voltage high
FMI 4Intake manifold 1 temperature sensor circuit voltage low
FMI 15Intake manifold 1 temperature high, least severe
FMI 16Intake manifold 1 temperature high, moderately severe

DAF

FMI 0Intake air temperature F649 too high, engine protection active
FMI 2Intake air temperature F649 implausible (extended period)
FMI 3Intake air temperature F649 short to power supply at ECU pin A11 (extended period)
FMI 4Intake air temperature F649 voltage too low at ECU pin A11 (extended period)
FMI 10Intake air temperature F649 implausible temperature
FMI 15Intake air temperature F649 temperature too high

Dongfeng

FMI 0Engine speed limitation caused by too high intake air temperature
FMI 2Incorrect intake air temperature signal. Scan tool code: P0096. Effect: Fan and warm-up control may misbehave.
FMI 3Short circuit to power or open circuit of the intake air temperature sensor
FMI 4Short circuit to ground of the intake air temperature sensor
FMI 10Intake air temperature signal not plausible (rate of change)
FMI 15Engine torque limitation caused by too high intake air temperature

Isuzu

FMI 3Boost temperature sensor fault (high voltage fault) (P1113)
FMI 4Boost temperature sensor fault (low voltage fault) (P1112)

KAMAZ engine (J1939)

FMI 0Intake air temperature sensor: physical range limit.
FMI 1Intake air temperature sensor: physical range limit
FMI 3Intake air temperature sensor.
FMI 4Intake air temperature sensor.
FMI 12Intake air temperature sensor

KAMAZ-5490 (Mercedes, K-line)

FMI is per the block maker's own table, not the J1939 table below.

FMI 0Intake temperature sensor: temperature too high. K-line code on KamAZ-5490: MR2 11822.
FMI 3Intake air temperature sensor: short to high. K-line code on KamAZ-5490: MR2 11215.
FMI 4Intake air temperature sensor: short to low. K-line code on KamAZ-5490: MR2 11216.

MAZ

FMI 0Charge air temperature sensor plausibility error - Plausibility error. Blink code: 6-1-2. Repair: Check the charge air temperature sensor and its wiring.
FMI 1Charge air temperature sensor plausibility error - Plausibility error. Blink code: 6-1-2. Repair: Check the charge air temperature sensor and its wiring.
FMI 3Air temperature sensor circuit fault - Voltage above allowed. Blink code: 2-3-3. Power will be reduced. Repair: Check the air temperature sensor and its wiring.
FMI 4Air temperature sensor circuit fault - Voltage below allowed. Blink code: 2-3-3. Power will be reduced. Repair: Check the air temperature sensor and its wiring.
FMI 12Air temperature sensor circuit fault - CAN bus signal implausible. Blink code: 2-3-3. Power will be reduced. Repair: Check the air temperature sensor and its wiring.
FMI 15EGR cooler fault - Implausibility error. Blink code: 6-1-9. Repair: Check the EGR cooler.

Renault Trucks

FMI 2Battery voltage too low. Repair: Check the voltage on the control unit pins (X1A/1, X1A/4, X1A/5, X1A/16, X1A/17). Switch the ignition off, switch it on again and repeat the test. If the fault persists, replace the control unit.
FMI 3Intake air temperature sensor — short to positive (5 V or battery voltage). Repair: Check the sensor and the wiring (J 1/15, J 1/35, J 1/36). Check the sensor and the engine wiring (A 2, A 19).
FMI 4Intake air temperature sensor — short to ground. Repair: Check the sensor and the wiring (J 1/15, J 1/35, J 1/36). Check the sensor and the engine wiring (A 2, A 19).
FMI 5Intake air temperature sensor — open circuit. Repair: Check the sensor and the wiring (J 1/15, J 1/35, J 1/36). Check the sensor and the engine wiring (A 2, A 19).

SITRAK

FMI 0Charge air temperature after intercooler above torque limit class 2
FMI 2Implausible charge air temperature signal after the intercooler. Scan tool code: P0096. Effect: Fan and warm-up control may misbehave.
FMI 3High voltage on charge air temperature sensor (after intercooler)
FMI 4Low voltage on charge air temperature sensor (after intercooler)
FMI 15Charge air temperature after intercooler above torque limit class 1
FMI 16Charge air temperature after the intercooler above the upper limit. Scan tool code: P007A. Effect: Fan and warm-up control may misbehave.
FMI 18Charge air temperature after the intercooler below the lower limit. Scan tool code: P007A. Effect: Fan and warm-up control may misbehave.
FMI 19Charge air temperature signal error on the CAN bus. Scan tool code: P0099. Effect: Fan and warm-up control may misbehave.

YaMZ

FMI 0Charge air temperature sensor signal plausibility error (Plausibility error). Blink code: 6-1-2. Repair: Check the charge air temperature sensor and its wiring.
FMI 1Charge air temperature sensor signal plausibility error (Plausibility error). Blink code: 6-1-2. Repair: Check the charge air temperature sensor and its wiring.
FMI 3Air temperature sensor circuit fault (Voltage above allowable limit). Blink code: 2-3-3. Power will be reduced. Repair: Check the air temperature sensor and its wiring.
FMI 4Air temperature sensor circuit fault (Voltage below allowable limit). Blink code: 2-3-3. Power will be reduced. Repair: Check the air temperature sensor and its wiring.
FMI 12Air temperature sensor circuit fault (CAN bus signal implausible). Blink code: 2-3-3. Power will be reduced. Repair: Check the air temperature sensor and its wiring.
FMI 15EGR cooler faulty (Plausibility error). Blink code: 6-1-9. Repair: Check the EGR cooler.

ZF AS-Tronic gearbox

FMI is per the block maker's own table, not the J1939 table below.

FMI 2Vehicle on-board electrical system voltage too low.

What FMI means in J1939

SPN 105 FMI 0105/0 · 105.0data above normal range (most severe level)
SPN 105 FMI 1105/1 · 105.1data below normal range (most severe level)
SPN 105 FMI 2105/2 · 105.2data erratic or intermittent
SPN 105 FMI 3105/3 · 105.3voltage above normal or shorted high
SPN 105 FMI 4105/4 · 105.4voltage below normal or shorted to ground
SPN 105 FMI 5105/5 · 105.5current below normal or open circuit
SPN 105 FMI 10105/10 · 105.10abnormal rate of change
SPN 105 FMI 12105/12 · 105.12faulty device or component
SPN 105 FMI 15105/15 · 105.15above normal — low severity
SPN 105 FMI 16105/16 · 105.16above normal — moderate severity
SPN 105 FMI 18105/18 · 105.18below normal — moderate severity
SPN 105 FMI 19105/19 · 105.19error in received network data

Can I keep driving

Safe to drive. Below — how much time you have and what happens if you keep going.

What happens if you keep driving

Time you have: Enough to reach the yard

Boost is not reaching its target: turbo, intercooler or intake. The engine compensates with mixture and runs hotter than usual.

You will lose pull, burn more fuel and add overheating on long climbs. If you hear a whine or a whistle from the turbo, stop — the wheel is breaking up.

This is an electrical fault: an open, a short or a bad contact in the sensor circuit. The value it measures is most likely fine. You can drive. But until the circuit is repaired this system runs blind and cannot warn you about a real failure.

What to check on the spot

Inspect the air filter and charge-air hoses: leaks and cracks produce exactly these codes.

Nearby: intake / boost

Makes with this code

KAMAZMAZYaMZSITRAKDongfengDAFRenault TrucksIsuzuCummins ISBKAMAZ-5490

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