Codes P0339, P2305, P0837, how to repair

CASMIHOK

MEMBER
2005 JEEP LIBERTY
3.7L
6 CYL
4WD
AUTOMATIC
160,000 MILES

Hello and thank you in advance for taking the time to read and respond.
My vehicle listed above Sport model is throwing these codes:

P0339 Crankshaft Position Sensor A Circuit Intermittent Stored
P2305 Ignition Coil B Secondary Circuit Confirmed
P0837 Four Wheel Drive Switch Circuit Range/Performance Stored

Tomorrow, I am going to pick up 6 new spark plugs. I intend to replace those and also do a little musical ignition coil (at the suggestion of Steve on here, thank you Steve) to see if my second cylinder ignition coil is causing problems.

I am going to purchase a crankshaft sensor but was wondering if you think that would fix anything. I am not sure if the spark plugs are also possibly affecting other electrical such as crankshaft, or if they are separate issues.

As far as P0837, what should I do? My Part time light is on almost all the time, and my car is always in 2Hi and I can't change it. So does that mean it's four wheel drive switch that needs replacing? Are transfer case switch and four wheel drive switch the same thing?

Also, a problem I haven't mentioned yet, I get no air blowing through unless it's on 4. I replaced the blower Motor resistor and that solved my problem for a month exactly. A month after I replaced the resistor, it stopped blowing on 1, 2, and 3 again. So does that mean my blower motor is always broken? Not just the resistor? Thank you, happy Halloween.

7 Replies

MASTERWRENCH

MECHANIC
258 POSTS

Good evening!

The P0837 code simply means the PCM is receiving an invalid signal from the transfer case position switch. In most cases, replacing the switch fixes this issue. It's located on the top side of the transfer case and is relatively easy to access (see the attached picture). This switch is mainly used for the light in the dash and shouldn't affect your ability to actually shift it in and out of 4wd. If you're unable to shift the transfer case, there's mostly likely more going on.

As for the blower issue, the blower motor is most likely beginning to fail. As a motor begins to wear out, it starts to draw more electrical current. This increase in current puts additional load on the blower motor resistor which can cause it to fail prematurely. At this point, I would replace the blower motor along with the resistor again. Below is the motor removal procedure.

1. Disconnect the wire harness connector from the blower motor.
2. Release the locking tab that secures the blower motor to the HVAC housing and rotate blower motor counterclockwise.
3. Rotate and tilt the blower motor as needed for clearance to remove the blower motor and wheel from the HVAC housing.

Let us know how you make out!

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Thursday, October 31st, 2019 AT 9:04 PM

CASMIHOK

MEMBER
204 POSTS

Thank you! What do you think about the crank shaft issue? Good idea to replace? Also I just turned me key on and off three times because I just learned that will flash codes and I got P0839 which is related to 4 wd and yes I am having trouble shifting to 4hi and I also got P0300 and p0311. Thank you!

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Thursday, October 31st, 2019 AT 11:33 PM

CASMIHOK

MEMBER
204 POSTS

Are the transfer case switch and four wheel drive switch the same thing? Thank you

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Friday, November 1st, 2019 AT 10:53 AM

MASTERWRENCH

MECHANIC
258 POSTS

The P0839 is also a transfer case position switch code, but it means the voltage on the sense circuit is above the normal range. It's still most likely a bad switch. And yes, in this case the transfer case switch and four wheel drive switch would be considered the same thing since it's a manual shift transfer case. Are you able to shift into any range beside 2Hi?

We try to keep the subject of each thread focused on one topic, so I would suggest keeping this one focused on your four wheel drive issue. Please continue working with Steve on your misfire/crank sensor issue. But in my opinion, I think replacing the crankshaft position sensor would be a good idea given the symptoms.

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Saturday, November 2nd, 2019 AT 2:26 PM

CASMIHOK

MEMBER
204 POSTS

Okay, thank you and sorry for being a mess when it comes to topics. Unfortunately I have three cars that need some work and not a whole lot of money but a lot of motivation to get it fixed under a budget and with the ability to learn, I believe I can do anything! Thanks again for all your help!

And honestly, I haven't messed too much with that because I truthfully wasn't knowledgeable and I don't do off roading. But the one time I did switch to 4HI, I got stuck. Luckily my buddy is a Jeep guy and I called him he told me it helps if the car is rolling and that let me get back into 2 lo. I stick to 2 lo currently.