BMW Service Engine Soon Light On? Lucas Auto Care Can Help!

What you need to know about your Service Engine Soon light:

  • It doesn’t mean you need an oil change!
  • SES lights come on when something causes the engine to not run correctly.
  • There is only one light so there is no way of knowing if there are multiple issues without doing testing.
  • Service engine soon lights can also be related to your transmission.
  • When the SES light comes on the performance of the engine will be lower. (Emission levels are a sign of engine performance, that’s why a check engine light won’t let your car pass state inspection if they test for emissions.)
  • Service engine soon, check engine, reduced performance and engine malfunction are all the same thing!

BMW 335i Service Engine Soon Lamp

We have a BMW 335i with a “Engine malfunction. Reduced power” message and a “Service engine soon lamp” shown on the display.

This message can be generated by several different failures, but in this particular BMW, the fault code is a 30FF. This is related to the turbocharger boost pressure control system, and shows us testing of this system will be required. Initial testing of this BMW found the fault was immediately set when the engine was put under turbocharger boost.

The BMW turbocharger pressure system is a complex one. Proper testing, in the correct order, is the most efficient way to find failures of this system. Knowledge of the system and its reaction to certain failures is extremely important to ensure a correct repair. Testing of this BMW found a failed attempt to repair to the vacuum lines that control the turbocharger pressure system.

In the case of this BMW 335i, once found, the repair was replacement of the turbocharger’s control vacuum lines. Due to the extreme heat generated by this system, we chose to replace the items with a higher quality silicone vacuum line. This resulted in an inexpensive and permanent fix.

BMW

BMW “Engine Malfunction/Reduced power” shown on display

Initial scan to determine cause of fault. Fault code 30FF is related to Turbo Boost.

Initial scan to determine cause of fault. Fault code 30FF is related to Turbo Boost.

Vacuum testing of turbo pressure control system. This one is working.

Vacuum testing of turbo pressure control system. This one is working.

Vacuum testing of turbo pressure control system. This one is faulty with very little vacuum signal.

Vacuum testing of turbo pressure control system. This one is faulty with very little vacuum signal.

A poor attempt at repairing the vacuum lines of the turbo system is found.

A poor attempt at repairing the vacuum lines of the turbo system is found.

Vacuum hose easily slips apart and is leaking at the repair attempt.

Vacuum hose easily slips apart and is leaking at the repair attempt.

Vacuum testing turbo pressure control after repair, the system is now working.

Vacuum testing turbo pressure control after repair, the system is now working.

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