Code Definition

P1105 — Dual Alternator upper fault

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

About P1105

P1105 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.

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

In Ford vehicles, the P1105 code refers to a Dual Alternator Upper Fault. It is set when the PCM detects a problem with the upper unit of a dual alternator charging system. Dual alternator systems are fitted to vehicles that need extra electrical capacity, such as those with high demand accessories, ambulances, and heavy duty or fleet applications, where two alternators share the charging load. A fault in the upper alternator, its field control, or its monitoring circuit can reduce charging capacity and lead to low system voltage, a discharged battery, and warning lamp operation, particularly ...

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