Code Definition

P1815 — 4WD Mode Select Switch circuit short to ground

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

About P1815

P1815 is a manufacturer-specific powertrain diagnostic trouble code recorded for Ford vehicles. 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 sets when the 4WD control module or PCM detects a short to ground in the 4WD mode select switch circuit. The mode select switch lets the driver request 2WD, 4WD High, or 4WD Low, and the module reads a specific voltage or resistance for each position to know which mode is requested. A short to ground pulls the signal below the valid range, so the module can no longer distinguish the switch positions and sets the fault. This commonly results from chafed wiring contacting the chassis or a contaminated connector bridging the signal to ground. The driver may find mode changes are ignored ...

Join TaT to view the complete code information and diagnostic details.

Quick Facts