Code Definition

P0383 — Glow plug pre heater control module Circuit low Circuit B

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About P0383

P0383 is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P0383 is stored, the module has detected a signal or supply voltage lower 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.

Because P0383 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

The powertrain control module (PCM) sets this code when it detects a low voltage condition in the glow plug pre-heater control module circuit for Circuit B. This typically indicates excessive resistance, a short to ground, or a failing control module. The glow plug system is essential for pre-heating the combustion chambers in diesel engines, and a low voltage condition can result in poor cold-start performance.

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