C056E on 2016-2020 Buick Envision (Preferred, Essence, Premium, Premium II) — Electronic Control Unit Software (Power Steering Control Module)
1 vehicles · 1 makes · $200-$1,500 repair
Most Reported On
C056E is an OBD-II diagnostic trouble code meaning “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. This code is most commonly reported on 2016-2020 Buick Envision (Preferred, Essence, Premium, Premium II), with repair costs ranging from $200 to $1,500.
Common Causes
Typical Repair Cost
Based on 1 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
This is a chassis code. A basic engine-code reader will not show it — you need a scanner that reads chassis modules. These read C056E.
One caveat that applies to every scanner: only powertrain codes are standardised across manufacturers. Body, chassis and network coverage is "enhanced" diagnostics, and how deep it goes varies by make and model year — check your specific vehicle against the tool's coverage list before buying.
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level tablet with all-system coverage and bi-directional control, so you can command a module rather than only read it.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
What you can do yourself, and what needs a shop
Reading the code, clearing it, and watching whether it returns is a driveway job with the right scanner. These steps are not:
- Module programming or software updates — needs the manufacturer software or a J2534 pass-through with a paid subscription.
- Replacing a control module — most are VIN-programmed and immobilizer-registered, so a new one does nothing until it is coded to your car.
- Airbag/SRS component work — a stored fault can deploy a live device.
If the vehicle is still under warranty, check for an open recall or technical service bulletin before buying anything — the repair may already be covered.
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FAQ
What does C056E mean?
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.
What are the most common causes of C056E?
The most common causes of C056E are: 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. The specific cause varies by vehicle.
How much does it cost to fix C056E?
Repair costs for C056E range from $200 to $1,500, depending on the vehicle and root cause.
Which vehicles are affected by C056E?
Au7o has documented C056E across 1 vehicle models from 1 manufacturers: Buick.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.