WrenchGuideAutomotive workshop companion
Workshop mode

COMPLETE GUIDE · WORKSHOP RELEASED

BMW fault-code and symptom baseline

BMW 3 Series Touring · E91 LCI · 320i · N43B20 · Any

A non-destructive diagnostic tutorial for recording symptoms, voltage context, control-unit fault codes and freeze-frame/live observations before any code is cleared or part is replaced.

4/4 steps released · 2 linked sources · about 35 minutes when released.

WHAT YOU WILL LEARNnovice path

FASTENER PLAN

Know what must be replaced before you start

WrenchGuide tracks fastener material, reuse policy and tightening specification separately. A torque-plus-angle instruction does not automatically mean a fastener is torque-to-yield or single-use; the replacement rule must be verified independently.

0mapped fasteners
No verified fastener map is published for this procedure yet.

WrenchGuide will not guess whether a bolt is aluminium, reusable, torque-to-yield or replace-after-removal, and it will not invent a torque value. Exact vehicle, engine, transmission and drivetrain applicability can change the answer.

Replacement rule and tightening method are different facts.WrenchGuide only labels a fastener replace-after-removal, aluminium or torque-to-yield when the applicable evidence supports that exact statement. Torque + angle is shown as a tightening method, not used as proof of torque-to-yield by itself.

BEFORE YOU START

Parts, tools & supplies

WrenchGuide builds this list from the repair itself. Mandatory items only become hard requirements after their need has verified provenance.

100%Verified requirements still being assembled
Job inventory pending technical verification.

The procedure can exist before its complete shopping/tool list does; WrenchGuide will not invent parts just to make this panel look complete.

Fitment and approval are separate checks.An OEM/reference number narrows a part search and an oil viscosity narrows a fluid search, but neither replaces the verified vehicle fitment or manufacturer approval. Production date, VIN, engine/transmission, installed hardware and current product data can still matter.
LEARNSTEP 1 / 4
WORKSHOP RELEASEDinfo

Write the symptom before connecting a tool

+
No visual needed for this step

Follow the written checks and use the linked sources when you need more context.

DO THIS~5 min
  1. Record exactly what the driver observed, when it happens, warning lights, sounds, smells and recent work.
  2. Distinguish 'engine shakes when cold' from a diagnosis such as 'bad injector'.
LEARN AS YOU GO
  • A fault code is one observation in a diagnostic story, not an automatic part order.
YOU ARE DONE WHEN
  • The baseline describes conditions and observations without assuming a cause.
TOOLS

No tools required for this step.

PARTS & SUPPLIES

No parts or supplies required for this step.

SOURCES & PROVENANCE2 linked

EdiabasLib / Deep OBD

Ulrich Holeschak / contributors · Open-source BMW EDIABAS-compatible diagnostics and E-series support · accessed 2026-08-13

specialist

BimmerGeeks ProTool

BimmerGeeks ProTool LLC · BMW diagnostics, control-unit errors and live data · accessed 2026-08-13

specialist
Progress saved locally on this device.

MY WORKSHOP JOURNAL

Remember how your car came apart.

Attach private notes and your own teardown photos to the exact procedure step. They stay on this device in the current local-first beta.

NOTESAuto-saved locally

Write the symptom before connecting a tool

MY PHOTOS0 / 6
Image only · up to 12 MB each
No personal photos for this step yet.

Take a quick photo before disconnecting or removing something you may need to identify during reassembly.