Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2009 Audi S4 AutomaticFACTORY OEM SERVICE PROCEDURE
4.2L - Generic Scan Tool, Engine Code(S): BHF
- 20 - Fuel supply
- 24 - Multiport Fuel Injection (MFI)
- Motronic fuel injection system, servicing
- Components, checking
- Oxygen Sensor (O2S) Heater Z19 f and Oxygen Sensor (O2S) 2 Heater Z28 before catalytic converter, checking.
- Oxygen Sensor (O2S) 1 (behind Three Way Catalytic Converter (TWC)) Heater Z29 and Oxygen Sensor (O2S) 2 (behind Three Way Catalytic Converter (TWC)) Heater Z30 , checking
- Mass Air Flow (MAF) Sensor G70 , checking
- Throttle Valve Control Module J338 , checking
- Engine Coolant Temperature (ECT) Sensor G62 , checking
- Engine Speed (RPM) Sensor G28 , checking
- Fuel Injectors N30, N31, N32, N33, N83, N84, N85, N86 , checking
- Function tests
- Heated Oxygen Sensor (HO2S) G39/Heated Oxygen Sensor (HO2S) 2 G108 and oxygen sensor regulation before catalytic converter, checking
- Oxygen Sensor (O2S) Behind Three Way Catalytic Converter (TWC) G130/Oxygen Sensor (O2S) 2 Behind Three Way Catalytic Converter (TWC) G131 and oxygen sensor regulation behind catalytic converter, checking
- Motronic Engine Control Module (ECM) J623
- Additional signals, checking
- 26 - Exhaust system, Emission controls
- 28 - Ignition/Glow plug System
- Ignition, servicing
- General notes on ignition system
- Safety precautions
- Test Data, Spark Plugs
- Camshaft Position (CMP) Sensor G40 and Camshaft Position (CMP) Sensor 2 G163 , checking
- Camshaft Adjustment Valve 1 N205 and Camshaft Adjustment Valve 2 (exhaust) N208 , checking
- Knock Sensor (KS) 1 G61/Knock Sensor (KS) 2 G66/Knock Sensor 3 G198/Knock Sensor 4 G199 , checking
- Ignition Coils with Power Output Stage N70, N127, N291, N292, N323, N324, N325, N326 , checking
- Ignition, servicing
- 38 - Automatic Transmission - Gears, Hydraulic controls
- Electrical components for regulating transmission O9L, checking
- Electrical components for regulating transmission O9L, checking
- Multi-Function Transmission Range (TR) Switch, checking
- Sensor for transmission RPM, checking
- Sensor for transmission output RPM, checking
- Transmission Fluid Temperature Sensor, checking
- Solenoid valve 1, checking
- Pressure regulator valves, checking
- Transmission Control Module (TCM) J217
- Continuously Variable Transmission (CVT) 01V, checking
- Electrical components for regulating transmission O9L, checking
- Generic Scan Tool
- On Board Diagnostic (OBD)
- Diagnostic modes
- Diagnostic Modes Description
- Diagnostic Mode 01: Obtain data
- Diagnostic Mode 02: Obtain operating conditions
- Mode 03: Interrogating fault memory
- Interrogating the Fault Memory
- Diagnostic Mode 04: Reset/delete diagnostic data
- Diagnostic Mode 05: Check lambda test results
- Notes
- Test-ID 01 ($01): Oxygen Sensor in front of Catalytic Converter Bank 1 - Sensor 1.
- Test-ID 02 ($02): Oxygen Sensor Behind Catalytic Converter Bank 1- Sensor 2
- Test-ID 05 ($05): Oxygen Sensor in front of Catalytic Converter Bank 2 - Sensor 1
- Test-ID 06 ($06): Oxygen Sensor Behind Catalytic Converter Bank 2 - Sensor 2.
- Diagnostic mode 6: Checking test results of components that are not continuously monitored
- Notes
- Mode 06 - $01 (01): Catalytic Conversion (Bank 1)
- Mode 06 - TID $01 (01): Catalytic Conversion (Bank 2)
- Mode 06 - TID $02 (02): Oxygen Sensor (Bank 1, Sensor 1)
- Mode 06 - TID $02 (02): Oxygen Sensor (Bank 2, Sensor 1)
- Mode 06 - $03 (03): Secondary Air Injection (AIR) System (Bank 1)
- Mode 06 - TID $03 (03): Secondary Air Injection (AIR) System (Bank 2)
- Mode 06 - TID $05 (05): Tank Ventilation System, Tank Vent Valve
- Mode 06 -TID $05 (05): Tank Ventilation System, Tank Leak Test
- Diagnostic Mode 07: Check test results of components that are continuously monitored
- Diagnostic Mode 08: Tank leak test
- Diagnostic Mode 09: Vehicle information
- Readiness Code
- Diagnostic Trouble Code (DTC) tables
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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