Cummins Fault Code

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Cummins 221

Engine Derate / Active CEL

System

Air Intake

Symptom

Engine Derate / Active CEL

Diagnosis & fix steps

LOGIC: Barometric Pressure Sensor Circuit - Voltage High (3) or Low (4). ACTION: Check the 5V reference at the sensor plug. Inspect for pins pushed back in the ECM connector.

Red Seal field insights

Specs: Voltage should be approx. 4.0V at sea level. PRO-TIP: This sensor is often built inside the ECM on older Celect/Signature engines; if the circuit is internal, the ECM needs repair.

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