Caterpillar Fault Code
Free · no signupMID 087 CID 0420 FMI 05
Secondary Steering Active / Alarm
System
Electrical / Steering
Symptom
Secondary Steering Active / Alarm
Diagnosis & fix steps
LOGIC: Secondary Steering Motor Relay Control Circuit Open.
ACTION: Measure auxiliary DC electric pump relay coil resistance (~35Ω). Inspect relay harness pass-through connectors behind the cab hydraulic access panel.
Red Seal field insights
Emergency Steering: If primary engine-driven steering pump flow drops, the ECM energizes this relay to start the DC emergency steering pump; an open circuit drops emergency backup.
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