P3055 on Buick
DC/DC Converter Actuator Voltage 1 Performance (GM)
P3055 on Buick vehicles indicates dc/dc converter actuator voltage 1 performance (gm). Au7o has documented this code across 1 Buick model — most commonly on Regal. P3055 is a manufacturer-specific code defined primarily by General Motors (Chevrolet, Buick, GMC) on vehicles with the auto stop/start system, such as the 2016-2021 Malibu, 2018-2021 Equinox, Blazer, Encore, and 2019-2021 Silverado/Sierra. When the engine shuts off at a stop, a DC/DC converter (GM calls it the Multifunction Power Supply Converter) boosts and stabilizes 12-volt power so the radio, instrument cluster, and electric power steering keep working; P3055 sets when the engine control module sees that converter's output voltage 1 fall out of spec, and it usually appears together with P3056. Drivers typically notice a check engine light with auto stop/start and remote start disabled, and sometimes flickering electronics, battery drain, or stalling during an auto-stop event. The car generally remains drivable, but ignoring it leaves the underlying battery, ground, or converter problem to worsen, which can lead to electrical glitches or a no-start. GM addressed this code in TSBs 18-NA-247 (poor ground connections) and 21-NA-139 (converter module replacement). Note: despite occasional association with Toyota/Lexus hybrids, Toyota's hybrid battery block codes run P3011-P3024 and P3055 is not documented among them; a few other manufacturers assign unrelated meanings to this code (e.g., a seat potentiometer circuit fault on some VW Touareg listings).
Common Causes of P3055
- •Failed DC/DC converter module (Multifunction Power Supply Converter, e.g., GM part 13514044 Malibu / 13510484 Equinox) — the most frequent fix per TSB 21-NA-139
- •Weak or failing main 12V AGM battery — load-test it before replacing the converter
- •Poor or corroded ground connections (G104, G107, G108) — addressed by GM TSB 18-NA-247
- •Failed or degraded auxiliary 12V battery (trunk-mounted on some models) that supports stop/start events
- •Damaged wiring or loose connectors in the DC/DC converter circuit
- •Incorrectly installed factory fuses in slots F51DR/F52DR on 2019-2021 Silverado/Sierra
- •DC/DC converter module misconfiguration or outdated programming
P3055 on Buick by Model
Buick Regal(1 issue)
- Sudden Loss of Electric Power Steering Assist (Recall)2016
GM recalled certain 2016 Regals (built Aug 2015 – Feb 2016) because a defective circuit board in the electric belt-drive rack-and-pinion steering gear could cause a sudden loss of power steering assist, sharply increasing steering effort and crash risk. Owners have also reported steering jolting or locking at speed. Beyond the formal recall, electric power steering faults (e.g., P3055/P3056 'Steering Assist Reduced' messages) are reported on later Regals.
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View P3055 across all makes →Frequently Asked Questions
What does P3055 mean on Buick?▼
P3055 stands for "DC/DC Converter Actuator Voltage 1 Performance (GM)." P3055 is a manufacturer-specific code defined primarily by General Motors (Chevrolet, Buick, GMC) on vehicles with the auto stop/start system, such as the 2016-2021 Malibu, 2018-2021 Equinox, Blazer, Encore, and 2019-2021 Silverado/Sierra. When the engine shuts off at a stop, a DC/DC converter (GM calls it the Multifunction Power Supply Converter) boosts and stabilizes 12-volt power so the radio, instrument cluster, and electric power steering keep working; P3055 sets when the engine control module sees that converter's output voltage 1 fall out of spec, and it usually appears together with P3056. Drivers typically notice a check engine light with auto stop/start and remote start disabled, and sometimes flickering electronics, battery drain, or stalling during an auto-stop event. The car generally remains drivable, but ignoring it leaves the underlying battery, ground, or converter problem to worsen, which can lead to electrical glitches or a no-start. GM addressed this code in TSBs 18-NA-247 (poor ground connections) and 21-NA-139 (converter module replacement). Note: despite occasional association with Toyota/Lexus hybrids, Toyota's hybrid battery block codes run P3011-P3024 and P3055 is not documented among them; a few other manufacturers assign unrelated meanings to this code (e.g., a seat potentiometer circuit fault on some VW Touareg listings). On Buick specifically, this code is documented across 1 model.
What causes P3055 on Buick vehicles?▼
Common causes on Buick: Failed DC/DC converter module (Multifunction Power Supply Converter, e.g., GM part 13514044 Malibu / 13510484 Equinox) — the most frequent fix per TSB 21-NA-139, Weak or failing main 12V AGM battery — load-test it before replacing the converter, Poor or corroded ground connections (G104, G107, G108) — addressed by GM TSB 18-NA-247, Failed or degraded auxiliary 12V battery (trunk-mounted on some models) that supports stop/start events, Damaged wiring or loose connectors in the DC/DC converter circuit. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P3055 on a Buick?▼
Repair costs vary widely depending on the root cause and specific Buick model.
Which Buick models have P3055 documented?▼
Au7o has documented P3055 on 1 Buick model: Regal.