Intermittent Bogging
08-19-2018, 07:03 AM
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Intermittent Bogging
A few months ago we ran in to a problem with our stock 2011 Rubicon (manual) randomly bogging (power decreases for half a second then returns to normal) while we were driving a steady 20 mph down a gravel road. When it was initially occurring I thought we were hitting patches of sand and didn't think the Jeep had a problem. Later that same day while driving up a steeper, looser gravel road the bogging became more frequent and threw a check enging light and then a stability control warning light. The check engine light began flashing and seemed to be misfiring so we stopped , restarted the Jeep and drove slowly back to where we were staying. The codes were P0339 and C121C. We have replaced the crankshaft position sensor and camshaft position sensor, first with aftermarket sensors and then with Mopar sensors, as well as replaced spark plugs and wires. The dealership has performed a relearning procedure after the crankshaft sensor was replaced with the Mopar part. The shop also tested the wire going to the camshaft position sensor and didn't find any issues. When they had the Jeep idling for 45 minutes it shut itself off, but they didn't have any further issues with additional idling or driving. This past weekend we picked the Jeep up from the shop and within 5 minutes of driving on a paved road in town (30 mph) the Jeep bogged. We were out of town and needed to return home so we continued the 4 hour drive back from Gunnison, CO to Denver. The Jeep drove flawlessly on the highways until we were about 20 minutes away from our house when we had two more instances of bogging. No check engine light or warning lights resulted from the brief losses of power.
Does anyone have any thoughts or recommendations on how to proceed to get this issue fixed? The problem seems to occur more frequently on looser surface roads (gravel, dirt trails), but doesn't always occur then. My concern with taking it to another shop or the dealership is that they won't be able to replicate the problem since it is so intermittent. Any help is much appreciated!
Does anyone have any thoughts or recommendations on how to proceed to get this issue fixed? The problem seems to occur more frequently on looser surface roads (gravel, dirt trails), but doesn't always occur then. My concern with taking it to another shop or the dealership is that they won't be able to replicate the problem since it is so intermittent. Any help is much appreciated!
08-19-2018, 07:13 AM
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Did you have a chance to check grounds under the hood to make sure they're clean and such? Also, any word on a new coil pack? If you've replaced the plugs and wires then that seems like the next step in your ignition chase.
08-26-2018, 05:13 PM
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Thanks for your response karls10jk. The grounds under the hood are nice and clean. I had not thought about the coil pack yet, but will keep that in mind as we further diagnose the issue. We ended up taking it back to our independent shop in Denver to see if they could come up with the source of the problem. After having it for two days they couldn't replicate the problem, but did find two service bulletins: 18-005-11 and 18-024-10. The short of the bulletins says that the Powertrain Control Module may need to be reprogrammed after replacement of the crankshaft position sensor. If that doesn't remedy the problem then a shim may need to be added to the crank sensor. If the shim doesn't solve it then replacing the flexplate on the transmission. Unfortunately this troubleshooting path requires taking our Wrangler to the dealership. I tried Friday and Saturday to call and schedule an appointment with no luck. Hopefully we can reach someone on Monday and try to get this issue fixed.
09-06-2018, 09:39 AM
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Quick update: I was able to drop the Jeep off at the dealership on Tuesday. They called Wednesday afternoon saying that they think it is the connector going to the crankshaft position sensor that is the problem. They are going to replace that and see if it fixes the problem. Hopefully we'll have a fixed Jeep this afternoon!
09-06-2018, 10:23 AM
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Me and at least one other member of the forum had momentary bogging as you described. Both of ours was fixed by replacing the crank position sensor, so it sounds like they are looking in the correct area.
09-14-2018, 04:19 AM
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Less than 24 hours after having the Jeep back in our possession we started having the same problems. The intermittent bogging wasn't as severe as before and didn't elicit the engine misfiring, but we did get a check engine light with the same "Cranshaft Position Sensor Intermittent" code. I dropped off the Jeep at the dealership again and after going through nearly half a tank of gas test driving it they were able to get the Jeep to have the same problem while the diagnostic equipment was hooked up. They say the powertrain control module has gone bad and will need to be replaced. Luckily that is still covered under some extended emissions warrant, but we will have to wait the 5 business days for the part to arrive. I'll update again when the new PCM is installed.
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10-11-2018, 05:32 PM
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Unfortunately we are still working with the dealership to get this problem resolved. Here is what has been performed so far:
The dealership replaced the PCM once it arrived and test drove it 4 different times over two day covering 90 miles over the different drives. They were confident they had it fixed so we picked it up from them. Within two days we started having the same issues again so we dropped it back off. Since they were having trouble diagnosing the problem (and my wife emailed Jeep corporate) the case become elevated to a STAR case in which the Jeep corporate engineers became involved. Fortunately we have their expertise in trying to fix the problem; unfortunately it has slowed down the troubleshooting as the dealership's technician has to wait to hear from corporate what to do, perform that request and then submit the data back to the Jeep engineers. Our Rubicon has now been at the dealership for three weeks undergoing this process. In that time they have replaced the PCM again, scoped the camshaft position sensor (the signal it was sending was fine), verified the crankshaft end play (which was well within spec) and finally have decided they need to hard wire the crankshaft electrical circuit. This involves eliminating the four connections along the path from the crankshaft position sensor to the PCM with electrical wire. I'm a little skeptical that this will fix it as they have already replaced the connection at the crankshaft position sensor (which involved cutting the wires a few inches up from the connector and soldering in a new one), but as the dealership told me when I questioned this they said "this is what the Jeep engineers recommend." I am going to assume that I am not going to get another update until Saturday at the earliest and will update this thread once I know more.
Good luck harrisonlr0921! I hope the fix for your Jeep is less painful than what we have been having to bear.
The dealership replaced the PCM once it arrived and test drove it 4 different times over two day covering 90 miles over the different drives. They were confident they had it fixed so we picked it up from them. Within two days we started having the same issues again so we dropped it back off. Since they were having trouble diagnosing the problem (and my wife emailed Jeep corporate) the case become elevated to a STAR case in which the Jeep corporate engineers became involved. Fortunately we have their expertise in trying to fix the problem; unfortunately it has slowed down the troubleshooting as the dealership's technician has to wait to hear from corporate what to do, perform that request and then submit the data back to the Jeep engineers. Our Rubicon has now been at the dealership for three weeks undergoing this process. In that time they have replaced the PCM again, scoped the camshaft position sensor (the signal it was sending was fine), verified the crankshaft end play (which was well within spec) and finally have decided they need to hard wire the crankshaft electrical circuit. This involves eliminating the four connections along the path from the crankshaft position sensor to the PCM with electrical wire. I'm a little skeptical that this will fix it as they have already replaced the connection at the crankshaft position sensor (which involved cutting the wires a few inches up from the connector and soldering in a new one), but as the dealership told me when I questioned this they said "this is what the Jeep engineers recommend." I am going to assume that I am not going to get another update until Saturday at the earliest and will update this thread once I know more.
Good luck harrisonlr0921! I hope the fix for your Jeep is less painful than what we have been having to bear.
12-03-2019, 06:08 PM
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Unfortunately we are still working with the dealership to get this problem resolved. Here is what has been performed so far:
The dealership replaced the PCM once it arrived and test drove it 4 different times over two day covering 90 miles over the different drives. They were confident they had it fixed so we picked it up from them. Within two days we started having the same issues again so we dropped it back off. Since they were having trouble diagnosing the problem (and my wife emailed Jeep corporate) the case become elevated to a STAR case in which the Jeep corporate engineers became involved. Fortunately we have their expertise in trying to fix the problem; unfortunately it has slowed down the troubleshooting as the dealership's technician has to wait to hear from corporate what to do, perform that request and then submit the data back to the Jeep engineers. Our Rubicon has now been at the dealership for three weeks undergoing this process. In that time they have replaced the PCM again, scoped the camshaft position sensor (the signal it was sending was fine), verified the crankshaft end play (which was well within spec) and finally have decided they need to hard wire the crankshaft electrical circuit. This involves eliminating the four connections along the path from the crankshaft position sensor to the PCM with electrical wire. I'm a little skeptical that this will fix it as they have already replaced the connection at the crankshaft position sensor (which involved cutting the wires a few inches up from the connector and soldering in a new one), but as the dealership told me when I questioned this they said "this is what the Jeep engineers recommend." I am going to assume that I am not going to get another update until Saturday at the earliest and will update this thread once I know more.
Good luck harrisonlr0921! I hope the fix for your Jeep is less painful than what we have been having to bear.
The dealership replaced the PCM once it arrived and test drove it 4 different times over two day covering 90 miles over the different drives. They were confident they had it fixed so we picked it up from them. Within two days we started having the same issues again so we dropped it back off. Since they were having trouble diagnosing the problem (and my wife emailed Jeep corporate) the case become elevated to a STAR case in which the Jeep corporate engineers became involved. Fortunately we have their expertise in trying to fix the problem; unfortunately it has slowed down the troubleshooting as the dealership's technician has to wait to hear from corporate what to do, perform that request and then submit the data back to the Jeep engineers. Our Rubicon has now been at the dealership for three weeks undergoing this process. In that time they have replaced the PCM again, scoped the camshaft position sensor (the signal it was sending was fine), verified the crankshaft end play (which was well within spec) and finally have decided they need to hard wire the crankshaft electrical circuit. This involves eliminating the four connections along the path from the crankshaft position sensor to the PCM with electrical wire. I'm a little skeptical that this will fix it as they have already replaced the connection at the crankshaft position sensor (which involved cutting the wires a few inches up from the connector and soldering in a new one), but as the dealership told me when I questioned this they said "this is what the Jeep engineers recommend." I am going to assume that I am not going to get another update until Saturday at the earliest and will update this thread once I know more.
Good luck harrisonlr0921! I hope the fix for your Jeep is less painful than what we have been having to bear.
01-01-2020, 11:51 AM
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Once they hard wired the crankshaft position sensor to the PCM we have not had any issues with the vehicle. Hopefully this helps you with your issue and it can be a simple fix for you!