Caterpillar Fault Code
Free · no signupSPN 1087 FMI 1
Brake Pressure Warning / Truck Derate
System
Braking / Air
Symptom
Brake Pressure Warning / Truck Derate
Diagnosis & fix steps
LOGIC: Service / Retarder Brake Secondary Air Supply Pressure Low.
ACTION: Inspect main air compressor governor unloader valve. Drain moisture from primary wet tank and inspect dual-circuit air check valves for internal leakage.
Red Seal field insights
Stopping Safety: Secondary air pressure must maintain sufficient reserve volume to actuate air-over-hydraulic service brakes during emergency stop conditions.
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