Code Definition

P1815 — Transmission 4-Wheel Drive Mode Select Short Circuit To Ground

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

About P1815

P1815 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 P1815 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.

P1815 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 set when the Powertrain Control Module (PCM) detects a short to ground in the 4WD mode select signal circuit. The mode select circuit provides information to the PCM or Transfer Case Control Module (TCCM) about the driver's selected transfer case range (e.g., 2HI, 4HI, 4LO). The expected signal is based on specific voltage levels or switch logic. A short to ground pulls the voltage below expected thresholds, resulting in an invalid input condition, prompting the PCM to log P1815.

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