BMW E90 Steering Column Switch Unit 6857941 - Used Original Parts

Diagnosis and Common Symptoms

From a workshop perspective, the Steering Column Switch Unit (SZL) is a frequent point of failure, primarily due to the integrated optical Steering Angle Sensor (LWS). A faulty SZL will compromise the Dynamic Stability Control (DSC) system, as it can no longer accurately read the driver's steering input.

Common On-Board Computer & Dashboard Errors:

• DSC and DTC Inactive / Malfunction
• Brake and Stability System Warnings (Often the "trifecta" of ABS, DSC, and yellow BRAKE lights)
• 4x4 System Malfunction (on xDrive models)
• Start-Off Assistance Inactive

Diagnostic Trouble Codes (DTCs) logged in the DSC module:

• 5EBA: Steering-angle sensor, plausibility
• 94B5 / 94B6: SZL: Steering Angle Sensor, internal fault
• D35A: DSC: Steering-angle sensor: angle invalid

Physical Symptoms:

• Turn signals fail to self-cancel after completing a turn.
• Cruise control becomes inoperative.
• Steering wheel-mounted buttons respond intermittently or not at all.

Introduction

The Steering Column Switch Unit (SZL) is the central command hub for your BMW's steering-related functions, critical for both driver controls and vehicle safety systems. This is a Genuine BMW part, carefully extracted from a donor vehicle to ensure 100% compatibility with the vehicle's complex electronic network. Each unit undergoes a rigorous bench test to verify the functionality of all stalks, buttons, and most importantly, the sensitive steering angle sensor, offering a reliable and cost-effective restoration of your vehicle's performance.

Product Details

• Brand: BMW

• Model Compatibility: E90, E91, E92, E93 (3-Series). May also fit E82, E84, E87, E88 models; verify part number.

• Part Name: Steering Column Switch Unit (SZL)

• Condition: Genuine Used (Tested Working)

• Notes: This unit houses the integrated Steering Angle Sensor (LWS). Post-installation, calibration of the new sensor is mandatory using diagnostic tools (such as ISTA, INPA, or equivalent). Depending on vehicle options (e.g., Rain Sensor, Active Cruise Control), VO coding may be required to ensure all features function correctly.