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 Donny Your Own Question
Donny
Donny, ASE Certified Technician
Category: Car
Satisfied Customers: 828
Experience:  A.S.E. Master Technician, Over 25 years working in Chrysler dealers, Top tech DaimlerChrysler 1998
8425921
Type Your Car Question Here...
Donny is online now
A new question is answered every 9 seconds

Grand Cherokee: The check engine light..scanner..popped..cylinder

Customer Question

The check engine light on my 05 Grand Cherokee came on. i used the OBDII scanner to find out why. It popped the code P3400 (cylinder deactivation system bank 1). So, what''s wrong with it and is it hard to fix?
Submitted: 8 years ago.
Category: Car
Expert:  Donny replied 8 years ago.

Hello

the code that you have involves the multiple displacement system for the hemi, full diagnoses may involve removal of the intake manifold or partial tear down of the engine, it may also be electrical in nature, i can give you the test if you feel that you can take apart the engine if needed, otherwise I would suggest taking it in to your local dealer to have it looked at

P3400-MDS RATIONALITY BANK 1

Possible Causes
INSUFFICIENT OIL PRESSURE ACTING ON THE LIFTER LOCKING PINS
OIL PASSAGES RESTRICTED
LIFTER
MDS SOLENOID

 

I hope that this helps you

If you need or want more information or help just let me know

Thank you

Donny