Limp mode

Tiny
DIVIDES
  • MEMBER
  • 2008 BMW 335
  • 6 CYL
  • TURBO
  • 2WD
  • AUTOMATIC
  • 183,000 MILES
Have several codes that may or may not be tied up to each other. Car will sometimes start from first time sometimes takes 10 times before it does, it will continue to crank but not start. Since it dos it is in limp mode, idle is fluctuating on its own up and down, and no throttle response. I suspect the relay code is the main one to look at, any ideas where to start and where this relay is?
Monday, September 13th, 2021 AT 12:12 PM

3 Replies

Tiny
DANNY L
  • MECHANIC
  • 5,648 POSTS
Hello, I'm Danny.

Since you car is in limp mode there most definitely is a code or codes stored for a vehicle fault. The first thing for you to do is perform a CAN scan. A CAN- Controller Area Network scan will test and retrieve all codes that are stored in your vehicles computer when your malfunction light is on. This scan will test all systems on your vehicle including the engine, brake, and transmission system. Here is a tutorial showing how to perform this scan:

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

After you perform this scan get back to us with any fault codes and we can then properly diagnose the issues you might be having on your BMW. Hope this helps and thanks for using 2CarPros.
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Tuesday, September 14th, 2021 AT 7:33 AM
Tiny
DIVIDES
  • MEMBER
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Even though the car does not struggle when I try to start it I just noticed it says 11.25v. Am gonna tickle charge it and see first. Plus am sure many of these codes are related or related to the low in battery charge. But here they are. First pic shows what the scanner asked me. I have never see this before, but both options are exactly the same.
I started the car after I deleted all codes after the can scan but the engine code is persistent and didn't go away. As soon as you start it there is a message of reduced power and the rom just revs on its own. Also the voltage is 13.8 when it started. As soon as I turned it off it started to drop to 11.40v.
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Tuesday, September 14th, 2021 AT 4:47 PM
Tiny
DANNY L
  • MECHANIC
  • 5,648 POSTS
Hello again.

Yes, 11.25V is too low for your car to function normally. The minimum voltage is usually 12.5 for normalcy. I would perform a charging system test first. Verify the alternator is outputting around 13.5-14.5V and your battery is in good condition. If the voltage keeps dropping on the battery when car is shut off it might not keep holding a charge. Here are a few tutorials for batteries:

https://www.2carpros.com/articles/how-to-charge-your-car-battery

https://www.2carpros.com/articles/symptoms-of-a-bad-car-battery

https://www.2carpros.com/articles/car-battery-load-test

First thing I would do is perform a battery load test to see if it will hold a charge. Most local auto parts stores will do this for free. Get back to us with the results and we'll go from there. Hope this helps and thanks again for using 2CarPros.

Danny-
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Wednesday, September 15th, 2021 AT 10:20 AM

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Related Engine Computer Limp Mode - Reduced Power Content

Reduced Power - Limp Mode
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Reduced Power - Limp Mode
The com­puter sys­tem that con­trols your car has a built in safety fea­ture called "Re­duced Power" or "Limp Mode" which is de­signed to get the car where it is...