This bulletin applies to 2013 BMW 328i models equipped with a heated steering wheel. Immediately following a cold start, if the heated steering wheel is switched on in addition to other electrical items such as heated seats, rear defroster, etc., it may switch off after 5 to 10 seconds.
This is an intermittent situation. Cycling the key will typically restore function.
For the first few seconds after start-up, voltage levels may dip momentarily when electrical items are switched on. If the supply voltage dips below the threshold for the heated steering wheel, it will be switched off.
The situation may be present even if the battery is properly charged and no charging system problems are present. Refer to ISTA diagnostics for the required repair procedures. Follow the test plan, using the latest ISTA version.
For vehicles built from Sept. 1, 2008, through May 20, 2009, select test plan W3233_WAS1 malfunction of steering wheel heater. For vehicles built after April 1, 2010, select test plan W3233_WAS2 malfunction of steering wheel heater.