Code Definition

P1806 — Transmission 4-Wheel Drive High Indicator Short Circuit To Battery

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

About P1806

P1806 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 P1806 is stored, the module has detected a short-circuit (voltage pulled to ground or to supply) in the monitored circuit; and a signal or supply voltage higher than the expected operating range.

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.

P1806 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

The powertrain control module (PCM) or transfer case control module (TCCM) sets P1806 when it detects a short circuit to battery voltage in the 4WD High indicator circuit. This condition occurs when the circuit receives constant voltage, causing the 4WD High indicator to stay illuminated or behave erratically.

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