120408 bmw b58 fix Reverse the lines at the pressure converter and this will correct your problem. ” Essentially, this code signals that the engine control module (ECM) has detected a problem with the turbocharger’s ability to control the charge pressure properly. At the end of the drive, I got drivetrain malufunction and reduced power. Thx!. Thx! i got codes 120308 (boost pressure control, plausibility: pressure too low) and 120408 (boost pressure control: shutdown as a follow-up reaction) these codes appear right after going into limp mode (drive train malfunction). The converter is mounted to the side of the valve cover and the lines were probably switched when the spark plugs were replaced. The BMW fault code 120408 translates to “Charge Pressure Control, Deactivation. 120408 - Charging pressure control: Switch-off as consequential reaction. Hopefully new boost pressure solenoid (s) is the problem. Thanks Robin750. Upon inspection the only problem that was obvious was the timing chain. The timing chain was still intact; however, the guides were in pieces. Well I think it's quite clear: you got a failure on the wastegate position sensor. Can these errors occur on a one-time basis??? There is a test procedure in ISTA for charging pressure, though I'm not sure if that tool supports it. I've also checked and replaced two vacuum hoses with silicon hosing. The diagnosis given to the owner was a catastrophic turbo failure. I checked the codes and among the ones i know of, I found 2 key ones: My question is - can these be tied to the spark plugs change or the engine cleanup? I've thrown a new wastegate pressure converter in the car, but still have the code, it was weird. I have seen it before on the N55 engine. This issue could be the pressure converter (boost solenoid) that controls wastegate activation using the vacuum system. Probably the wastegate has been therefore deactivated and the engine no longer gets the desire boost, triggering the second failure. Get the sensor replaced and delete the failures. I have replaced the timing chain. After the warning lamp has occurred, there has been continuous 2 to 3 high rpm and high speed driving, but there will be no warning lamp again. Barbera335 - You are right, problem solved, thank you!!! According to the content of the site you mentioned, it appears to be an error in the electronic part or a error in the charging pressure sensor. When I received this vehicle, it was not running. I’m having problems with my 340i b58 gen 1. i got codes 120308 (boost pressure control, plausibility: pressure too low) and 120408 (boost pressure control: shutdown as a follow-up reaction) these codes appear right after going into limp mode (drive train malfunction). jmuvwk vhi yzfkjhg heswqc gph zbufrl slby zrwnqu xbqrpp qszh