Code Definition

P1105 — Dual Alternator Upper Fault

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

About P1105

P1105 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.

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.

P1105 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 P1105 fault code specifically refers to a 'Dual Alternator Upper Fault.' This code is set when the Powertrain Control Module (PCM) detects a problem with the upper unit of a dual alternator system. Dual alternator systems are often used in vehicles that require more electrical power, such as those with high-demand electrical accessories or heavy-duty applications. The upper alternator fault indicates an issue in the charging system, which could affect the vehicle's electrical stability and battery charging efficiency.

Quick Facts