Hi, I have a 2014 Cherokee Limited 3.2 V6 at 79K miles. It popped up P0204 and P0304 error codes yesterday.
P0204: Injector Circuit / Open Cylinder 4
P0304: Cylinder 4 Misfire Detected
I checked the oil level and it was quite low. I searched online and it seems the oil cooler leak is a common problem for this engine.
Will the oil leak cause the misfire in this engine? Thank you!!!
Hi
@2014cherokeelimited ,
In most cases not. Your two codes are indicating Injector 4 is not working properly (P0204) which generally means it is not firing some of the time or not at all leading to the P0304 code (Cyl 4 misfire). In other words,
Cause (P0204) and
Effect (P0304).
The low oil could be due to one of several issues from (1) natural loss/burn off depending on when you changed it last to (2) a leak from the oil cooler or elsewhere. Either way, it's almost always not related to anything injector-specific since the injectors deal with the fuel (gas) and spark part of the engine, not oil delivery.
Have you/are you comfortable working on your car? Have you taken off your air intake or other parts before? Both of these items, a bad injector and oil cooler, can be inspected and replaced by a competent home mechanic or you could take it to a shop or dealer. Note, the fixes required for both aren't Jeep-dealer specific, any mechanic could do it which will save $$$.
If you are comfortable yourself with your engine:
- Remove the air intake and find injector 4. It's the middle cylnder on the front side of the engine nearest the hood release. is there any sign of "trauma" (wire damage, possibly caused by mice, squirrels making a warm nest for the winter.) It's actually very common. They gnaw on the wires. See the photo below of one I just did a couple months ago with mouse gnawing on the wires (unfortunatly for him, he died there too. RIP little mousie) If there's no wiring damage, I'd unplug the injector and using a multitester on a low ohm setting, see if it provides between 10-20 ohms of resistance. Anything outside that, the injector is bad and needs to be replaced. They're about $100 each at your Jeep dealer or Napa auto store.
If all ok until now, there are a couple other things to do (including running some injector cleaner through the fuel system) but I'd check the above first.
