P1871: Transmission Mechanical Transfer Case 4x4 Switch Circuit Short To Battery

What does P1871 mean?

P1871 is a diagnostic trouble code indicating "Transmission Mechanical Transfer Case 4x4 Switch Circuit Short To Battery". The ECU is detecting a voltage reading that is below the expected range in the transmission circuit. This typically points to a wiring short, a faulty sensor, or a grounding issue.

Common causes

• Damaged or corroded wiring harness
• Loose or disconnected electrical connector
• Failed transmission sensor or actuator
• Blown fuse in the related circuit
• Poor ground connection

What should you do?

Schedule a diagnostic appointment at your earliest convenience. The vehicle is generally safe to drive short distances, but the underlying issue should be addressed to prevent it from worsening.

Get a diagnosis for YOUR car

Code P1871 can mean different things depending on your vehicle. TorqueBot gives you a diagnosis specific to your make, model, and year.

Related codes