S4 V8-4.2L (BHF) (2004)
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Variable Valve Timing Actuator: All Technical Service Bulletins
Engine Controls - MIL ON/DTC P0300-P0308/Runs Rough
01 MIL on, engine runs rough after hot start (DTC P0300 - P0308 in ECM)
24 10 24
2017310/3
June 4, 2010
Supersedes Technical Service Bulletin Group 24 number 08-50 dated November 18, 2008 for the reasons listed below.
Affected Vehicles
Condition
The customer may report:
^ Engine may run rough after a hot start for 3-4 seconds.
^ The MIL may be on, and DTCs P0300 P0308 may be stored in the ECM memory.
Technical Background
The intake Camshaft Adjustment Valves N205 and N208 are not controlled fast enough during hot start conditions. This may lead to rough running
engine with random misfiring cylinders.
Production Solution
New software in the Engine Control Module (J623) resolved the hot start misfires.
Service
Please explain to customers that this new software is the latest software level, with improved driving characteristics. This includes the following changes:
^ The exhaust flap (if equipped) is always open and no diagnosis of the Exhaust Flap Valve N321 is possible. Up to 1,700 rpm the engine is a bit louder,
as the exhaust flap is always open.
^ Faster throttle over-run cut-off, with more direct accelerator pedal and reduced overrun after releasing the accelerator.
^ When accelerating from a stop, the engine torque is slightly reduced when vehicle speed is below 20 mph and the engine speed is higher than 4600
rpm. This prevents the clutch from slipping. There is no noticeable performance difference.
SVM Update Instructions
1. Follow all instructions in the attached TSB 2011732 00 Software Version Management (SVM), operating instructions.
