How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Mike V. Your Own Question
Mike V.
Mike V., Subaru Technician
Category: Subaru
Satisfied Customers: 23822
Experience:  Certified Subaru Technician, factory trained by Subaru.
2921078
Type Your Subaru Question Here...
Mike V. is online now
A new question is answered every 9 seconds

Check engine light is ON. code P0400. The housing which

Customer Question

Check engine light is ON. code P0400. The housing which mounts the EGR valve has grayish water at the bottom. Somewhere I read that this indicates another small valve problem which triggers P0400.What happens next?
Submitted: 1 year ago.
Category: Subaru
Expert:  Mike V. replied 1 year ago.

Hi there,

If you look at the engine you should see a round plastic disk looking item. This is the BPD valve. It regulates some of the vacuum to the egr. If you pull it off and tap it on your hand you might get some water out of the bottom hose. If you do, replace it. This is the most common cause of the 400 code on these.

Please let me know what more I can do to assist you today. Also, please remember to rate my answer, Just Answer does not compensate me for my time and resources. Follow up questions are included in the price of your question. If you are using the free trial, a rating is still required.
Thank you so much!

Related Subaru Questions