C056E on Buick
Electronic Control Unit Software (Power Steering Control Module)
C056E on Buick vehicles indicates electronic control unit software (power steering control module). Au7o has documented this code across 1 Buick model — most commonly on Envision. General Motors chassis code stored by the Power Steering Control Module (PSCM). It reports a software/calibration integrity problem inside the steering control unit rather than a failed external sensor: the module either has no valid calibration data set, has a corrupt or mismatched calibration, or fails an internal software integrity check. The best-documented case is symptom 42 (calibration data set not programmed), which GM describes as latching when a steering gear assembly is installed without being programmed through SPS — the steering feels normal at first, then the module latches the fault and drops assist. Other symptom suffixes cover other internal software/calibration faults. When the code latches the PSCM stops providing assist, leaving heavy manual steering. Typical repair costs on Buick range from $200 to $1,500, depending on the specific model and root cause.
Common Causes of C056E
- •Steering gear / rack or PSCM replaced without SPS programming and calibration (symptom 42)
- •Corrupt or interrupted software update to the power steering module
- •Outdated PSCM software requiring a reflash per a GM bulletin
- •Low or unstable supply voltage / poor power and ground at the PSCM causing failed writes
- •Internal PSCM failure requiring replacement of the steering gear assembly
C056E on Buick by Model
Buick Envision(1 issue)
- Sudden Loss of Electric Power Steering Assist with DTC C056E-5A2016-2020
Envision owners report the steering going completely heavy or the wheel effectively locking, sometimes at highway speed during a merge and sometimes on the restart phase of the auto stop/start cycle. One NHTSA complaint describes total loss of assist lasting about five minutes that only cleared after an engine restart; another describes needing extreme force to regain control at 50 mph. GM TSB 17-NA-340 covers power steering service messages with loss of assist and DTC C056E-5A, which points at the power steering module supply circuit rather than a mechanical rack failure.
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View C056E across all makes →Frequently Asked Questions
What does C056E mean on Buick?▼
C056E stands for "Electronic Control Unit Software (Power Steering Control Module)." General Motors chassis code stored by the Power Steering Control Module (PSCM). It reports a software/calibration integrity problem inside the steering control unit rather than a failed external sensor: the module either has no valid calibration data set, has a corrupt or mismatched calibration, or fails an internal software integrity check. The best-documented case is symptom 42 (calibration data set not programmed), which GM describes as latching when a steering gear assembly is installed without being programmed through SPS — the steering feels normal at first, then the module latches the fault and drops assist. Other symptom suffixes cover other internal software/calibration faults. When the code latches the PSCM stops providing assist, leaving heavy manual steering. On Buick specifically, this code is documented across 1 model.
What causes C056E on Buick vehicles?▼
Common causes on Buick: Steering gear / rack or PSCM replaced without SPS programming and calibration (symptom 42), Corrupt or interrupted software update to the power steering module, Outdated PSCM software requiring a reflash per a GM bulletin, Low or unstable supply voltage / poor power and ground at the PSCM causing failed writes, Internal PSCM failure requiring replacement of the steering gear assembly. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix C056E on a Buick?▼
Repair costs on Buick range from $200 to $1,500, depending on the specific model and root cause.
Which Buick models have C056E documented?▼
Au7o has documented C056E on 1 Buick model: Envision.