Code Definition

P1873 — Transmission Mechanical 4-Wheel Drive Axle Lock Lamp Circuit Short To Battery

System: Powertrain  |  Type: Manufacturer-Specific  |  Make: Generic

About P1873

P1873 is a manufacturer-specific powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1873 is stored, the module has detected a short-circuit (voltage pulled to ground or to supply) in the monitored circuit.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

P1873 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

This DTC is specific to a short to battery voltage in the four wheel drive axle lock indicator lamp circuit. The transfer case control module normally illuminates this lamp by providing a ground through a low side driver. DTC P1873 sets when battery voltage is present on the control side of the circuit where it should not be, indicating a short to power that prevents proper lamp control. The axle lock indicator may light when it should be off, and a persistent short can damage the module lamp driver.

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