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Urbunner 6/30/2020

2010 Jeep Compass Limited 4 Cyl 2.40L


Misfiring after crankshaft sensor replacement

I have a 2010 jeep compass and got a po300 code indicating a bad crankshaft sensor. Put a new sensor in. Drove it around about 20 minutes and it seemed like the sensor relearned and the car was driving fine. The past 2 days it started out missing and sputtering and I had to drive it around 20 minutes till it was fine again. What are possible reasons for this?

1 Answer


EaOutlaw 8/8/2020

A P0300 is a general misfire code when two or more cylinders are misfiring not something that is normally caused by a bad crank sensor. Most likely your old crank sensor was just fine.
If this was my vehicle I would start by giving the Jeep a good inspection checking all the fluids and filters while the engine is cold. look at and smell the engine oil does it smell like raw fuel? does it look like a nasty looking milkshake? is the coolant full does it look weird like it has oil in it?
If the basics look like they are in good shape how many miles does the engine have on it?
This Jeep is at the age where poor preventive maintenance and age could be intersecting. So lets get to the meat and the potatoes of the problem with a few basic test. First and most important check the compression on each cylinder of the engine while closely inspecting the spark plugs to look for any plug that looks different than the other ( there are many charts online to show you how to read a spark plug )
If you have low compression on any or all cylinders a leak down test will reveal the cause of the low compression. If the compression is good and the plugs look and read like normal plugs it is safe to reinstall them.then post your findings here. and I will have other suggestions for you.


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