B101D on Buick
ECU Hardware (Control Module Internal Hardware Performance)
B101D on Buick vehicles indicates ecu hardware (control module internal hardware performance). Au7o has documented this code across 1 Buick model — most commonly on Encore GX. General Motors body-code definition. When power-up is commanded, the control module runs an internal self-test that requires only battery voltage, ignition voltage and ground; that test runs even when supply voltage is outside the normal operating range. B101D sets when the module detects an internal hardware malfunction during that self-test — the failure is inside the ECU itself, not in an external sensor or actuator. The two-character symptom suffix (e.g. B101D-00, -31, -39, -3B, -F0) narrows which internal element failed. Because this code can be stored by any GM body module, the affected function depends on which module reported it (e.g. a Power Steering Control Module for a lane-keep/steering complaint, a Seat Module for a Safety Alert Seat complaint). Typical repair costs on Buick range from $200 to $600, depending on the specific model and root cause.
Common Causes of B101D
- •Internal failure of the reporting control module (ECU hardware fault) — the module is normally replaced and programmed
- •Corrupt or incomplete software/calibration in the module after a failed SPS programming event
- •Severe under- or over-voltage events, jump-start spikes or a failing battery stressing module internals
- •Water intrusion or corrosion inside the module housing
- •Poor power/ground supply to the module causing repeated resets
B101D on Buick by Model
Buick Encore GX(1 issue)
- Lane Keep Assist Steering Intervention Pulling the Vehicle Toward Oncoming Traffic2023-2025
On later Encore GX models the Lane Keep Assist with Lane Departure Warning system applies an inappropriate steering torque that pulls the vehicle across the centerline rather than back into the lane. NHTSA complaints describe a sudden, forceful takeover of the steering wheel toward oncoming traffic, requiring the driver to fight the system. CarComplaints lists Lane Assist as the leading reported problem on the 2025 model year. The behavior appears tied to camera misinterpretation of lane markings - faded lines, tar seams, construction striping, shadows and crest transitions - compounded by camera calibration that was never performed or was performed incorrectly after a windshield replacement.
Looking for B101D on a different make?
View B101D across all makes →Frequently Asked Questions
What does B101D mean on Buick?▼
B101D stands for "ECU Hardware (Control Module Internal Hardware Performance)." General Motors body-code definition. When power-up is commanded, the control module runs an internal self-test that requires only battery voltage, ignition voltage and ground; that test runs even when supply voltage is outside the normal operating range. B101D sets when the module detects an internal hardware malfunction during that self-test — the failure is inside the ECU itself, not in an external sensor or actuator. The two-character symptom suffix (e.g. B101D-00, -31, -39, -3B, -F0) narrows which internal element failed. Because this code can be stored by any GM body module, the affected function depends on which module reported it (e.g. a Power Steering Control Module for a lane-keep/steering complaint, a Seat Module for a Safety Alert Seat complaint). On Buick specifically, this code is documented across 1 model.
What causes B101D on Buick vehicles?▼
Common causes on Buick: Internal failure of the reporting control module (ECU hardware fault) — the module is normally replaced and programmed, Corrupt or incomplete software/calibration in the module after a failed SPS programming event, Severe under- or over-voltage events, jump-start spikes or a failing battery stressing module internals, Water intrusion or corrosion inside the module housing, Poor power/ground supply to the module causing repeated resets. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix B101D on a Buick?▼
Repair costs on Buick range from $200 to $600, depending on the specific model and root cause.
Which Buick models have B101D documented?▼
Au7o has documented B101D on 1 Buick model: Encore GX.