SPN 1172 — Turbo inlet temperature sensor low

SPN 1172 is the parameter the ECM is flagging on International, CAT, Detroit, PACCAR, MERCEDES, Volvo, Mack, Cummins engines. The FMI that comes with it tells you how it failed. Each failure mode below has its own causes and its own test order — do not treat them as the same repair.

FMI 4 · Voltage below normal or shorted to low source

Turbocharger compressor inlet temperature sensor voltage low

The signal is pinned low — usually the signal wire touching ground, or the 5 V reference lost.

FMI 4 · Voltage below normal or shorted to low source

Turbocharger compressor inlet temperature sensor voltage low

The signal is pinned low — usually the signal wire touching ground, or the 5 V reference lost.

FMI 4 · Voltage below normal or shorted to low source

Turbocharger compressor inlet temperature sensor voltage low

The signal is pinned low — usually the signal wire touching ground, or the 5 V reference lost.

FMI 4 · Voltage below normal or shorted to low source

Turbocharger compressor inlet temperature sensor voltage low

The signal is pinned low — usually the signal wire touching ground, or the 5 V reference lost.

FMI 4 · Voltage below normal or shorted to low source

Turbocharger compressor inlet temperature sensor voltage low

The signal is pinned low — usually the signal wire touching ground, or the 5 V reference lost.

FMI 4 · Voltage below normal or shorted to low source

Turbocharger compressor inlet temperature sensor voltage low

The signal is pinned low — usually the signal wire touching ground, or the 5 V reference lost.

FMI 4 · Voltage below normal or shorted to low source

Turbocharger compressor inlet temperature sensor voltage low

The signal is pinned low — usually the signal wire touching ground, or the 5 V reference lost.

The reference is free. The diagnosis is Pro.

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