Code Definition

P1108 — Dual Alternator Battery Lamp Circuit Malfunction

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

About P1108

P1108 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 P1108 is stored, the module has detected an electrical-circuit fault in the wiring, connector, or driver associated with the named component.

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.

P1108 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 code is set when the powertrain control module (PCM) detects an issue with the battery warning lamp circuit in a dual-alternator system. The circuit is responsible for illuminating the battery warning light when a charging system fault occurs. If the PCM detects an open, short, or unexpected voltage condition in this circuit, it triggers P1108.

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