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Discussion Starter #1
I have a 2006 commander with the 3.7.this code has been on for a month or 2. it recently faile insp and they gave me these codes.ive also checked it with a small code scanner and got the same thing.the p0300 apparently means random misfire so I cant pinpoint the exact location but the p1052 says manifold absolute pressure sensor out of limits.
could this be causing the random misfire too?
the map sensor is about 25 bux ,do you think this will solve the problem?
thank you in advance!:smile2:
 

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Discussion Starter #2
we took it to autozone a few weeks back and they said the throttle pos sensor was bad.we changed it but it seemed as if it ran even a bit worse after we switched it.we took it to autozone again last nite and got the same 2 codes.the random misfire could be caused by bad plugs right?we bought new plugs so I guess we will try that first.
 

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How many miles on the vehicle?


The PCM picks up misfires by noticing a change in the crankshaft speed. If one cylinder fails to fire and burn correctly, it will NOT give the push to the crank that it should and the crank will slow down slightly until the next cylinder fires correctly.



So just about anything that would cause less than perfect burning in that cylinder can cause a misfire.


Spark Plugs are a common one, and you should catch up with any overdue maintenance for the engine. Check the O.M. how often should your plugs be changed? Most 3.7L, its every 30k miles, if you're overdue for a plug change the plugs could be eroded away and NOT making a good spark and often does cause misfires.


Ignition wires do deteriorate over time and with use earlier 3.7L had a coil per each plug, so you just have to inspect the boots and makes sure they are still good, later 3.7L had a wasted spark system, with coils on half the cylinder and a spark plug cable going to the other cylinder. If one of those cables are bad, that could cause misfires.

Air filter, unlikely, it would have to be incredibly clogged to cause misfires, but if the air filter has never been changed on your vehicle its possible its that clogged.

Dirty or fouled fuel injectors can cause misfires.

Bad fuel or water in the fuel can cause misfires.

Try some fuel injector/gas treatment, Chevron Techron is the best cleaner IMO and the only one recommended by Chrysler.

Vacuum leaks can cause misfires, check all your hoses and the intake manifold and throttle body. The MAP sensor measures the vacuum in the manifold, so if the vacuum was off in the manifold, that could be throwing off the MAP sensor and causing the P1052 code you're getting.

The 3.7L intake manifold is bolted down with most of its bolts also being the coil pack bolts, so if one or more coil pack was removed to change plugs and then not torqued down correctly, it might cause a leak in the intake manifold, perhaps causing your problems.

Finally, I had a P0302, which is a misfire in the #2 cylinder. I checked and tried everything and it kept coming back. I finally figured out it was the seals on the plastic intake manifold that were leaking. When I replaced the seals it solved the misfires and the engine ran much smoother and got better mileage. Unfortunately, since the engine compartment is so cramped, it takes a ton of work to get the intake manifold out to replace the $10 worth of seals. Took me a day and half to do it. If you're going to pay a shop to do it, the labor will be a lot.

I had a 130k miles on my motor when I replaced the seals, from what I saw it looks like it would be a common thing on higher mileage motors.

One thing I did to identify it was the seals on the intake manifold, since everything I tried before this didn't work. Was to tighten down the intake manifold bolts a little more than they were, that improved the situation greatly, sprayed a little oil into the gap between intake manifold and head, where the seal was leaking, that solved the situation totally. But that oil filling the leak would last a few days, so I got all new seals.

And one last thing I learned, in case this turns out to be your problem. Its a lot of extra work to make the room to get the intake manifold out completely. BUT, you don't need to get the intake manifold out completely to replace the seals, you can probably do the job in half the time, if you just unbolt what is necessary to raise the intake manifold and pull out the seals and put in the new ones, wipe the surfaces clean with a rag.

Since its a plastic intake manifold it uses a different kind of seal, it doesn't bake on and you just need to wipe the surface down with a rag to clean it.
 

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Discussion Starter #4
thank you!
we will look into everything tonite when we change the plugs.
I suspected a vac leak originally and sprayed starter fluid near all of the areas I thought it might be including the map sensor but got nothing.
 

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Discussion Starter #5
we changed the plugs last nite.the electrode was completely eroded away on all of the plugs.the gap was probably .100 when its supposed to be .035.
we started it up and it idled nice for about 30 sec then it started running rough and the cel started blinking.
after a few revs it seemed to clear up and run smooth again.
hopefully it will run better today.
if the plugs were the problem how long will it take for the cel lite to go off?
 

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Discussion Starter #6
started up nice and the cel stayed solid all the way to work this morning.it was blinking and not running well at all on 1st start up till it got warmed up.im hoping the cel will go out in a bit.
 

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Are you sure the spark plug gap is suppose to be 0.035", I'm pretty sure its suppose to be 0.043". You might want to confirm that, because if you've narrowed the gap down by 0.008", it might cause problems, and likely the same as you have had.


If you make a huge change to the engine, that changes its tune, its NOT uncommon for the motor to run rough and stall on first start, and maybe a bit rough for as much as 50-75miles until the motor has had a chance to fully retune itself. Considering how eroded away your plugs were, that might cause this, as well, if you've gapped the plugs wrong, you might have induced this.


I have a 2010 3.7L, so its possible the plug gaps changed from 2006 to 2010. But NOT often, I would look into the proper plug gap and correct it if you were wrong, especially if you continue to have problems.


You should have cleared the DTC's and CEL, either erase with an OBDII tool or simply reset the PCM by pulling the battery cable for a half hour. That way you will know if you've corrected the problem or NOT. If the CEL and DTC's come back, you haven't corrected it. Right now, you have no clue if you've corrected it or NOT, and are just waiting hoping the light goes out on its own some time down the road.

But, you're right, the light should eventually go out, you'll still have the DTC's for a while after that, as historical record.
 

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The Code P1052 isn't related to the ignition.


Its possible, the spark plugs in such bad conditions that resulted in the poor engine running, could have caused additional codes. So it might have corrected both codes.


Again, if you had cleared the CEL and DTC's and the code P1052 came back right away, that would tell you had two problems and you only corrected one.
 

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Discussion Starter #9
so its still running very badly and probably worse now.on start up if my son revs it up a bit it seems to jump up and down like its bouncing off of a rev limiter or something.
we stopped at autozone and the same 2 codes are still there.
this time they suggested injectors,but wouldn't that throw a code by itself?they didn't know.
we thought the plugs would clear things up but they didn't so now we are going to change the front pass side oxygen sensor.
we didn't change it before because we thought the plugs may be the cause of all of the problems.
at this point im tired of just guessing and throwing parts at it.
 

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I would take what Autozone says with a grain of salt.


Have you confirmed you gapped the plugs to the correct gap? Cause I don't think 0.035" is the correct gap for your 3.7L, my 3.7L the gap is 0.043". There is a few years between, so its possible I'm wrong, but if I'm right, the incorrect gap on your new plugs could cause problems.


You're still getting a code for a MAP sensor, and you haven't changed it? I have no idea why Autozone salesmen would suggest you have a bad TPS when the code says MAP sensor. The MAP sensor is a huge input into the PCM for it to determine fuel input, if the sensor is bad, it can make the engine run horribly. Again, take what an Autozone salesman says with a grain of salt.


Dirty Fuel Injectors? The PCM sets codes for misfires when it sees the crank speed slow down between cylinder firings. So anything that causes a cylinder to NOT fire correctly, can set a misfire. Ignition, especially if you have overdue spark plugs is the first suspicion. But fuel injectors NOT injecting the correct amount of fuel can cause it, (bad MAP sensor can cause the PCM to tell the fuel injectors to inject the wrong amount of fuel) dirty injectors can inject the wrong amount fuel and inject it in a stream, instead of mist which will effect the burning. Vacuum leaks, or leaks in the intake manifold, etc.


A bottle of Chevron Techron in the fuel tank can't hurt, it will clean dirty injectors, it works better than a lot of cheaper bottles that often don't do anything.


NOT sure on the Commander, but most Chrysler products since the late 90's with automatic transmissions, the PCM lowers the Rev Limiter drastically when the automatic transmission is in neutral. Like 3000rpm. So when you son is trying to rev it up in park/neutral, he very well may be hitting the Rev Limiter. Also, the Engine hitting a wall like a Rev Limiter at lower RPM is a sign of a bad MAP sensor, which you have a code for, but let the Autozone salesman talk you out of replacing.......
 

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Also, you do NOT need to stop at autozone to have your codes read by them. You can do the Chrysler key dance, search Youtube for a video showing you how to do it. Just turning the key on/off 3 times to end at "ON" without starting the motor and the stored codes will read out in the EVIC (the little warnings on the dash).
 

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Yea, I just googled it, I see it several times as Bank1/1 O2 sensor.


You need to find the references, are the banks 0 and 1 or are they 1 and 2? Same for sensor position.
Cause if its bank 1 and 2, then bank 1 would be the Driver's side O2 sensor
If its sensor position 1 and 2, then sensor 1 would be the Upstream O2 sensor, the one closest to the engine.


If its bank 0 and 1, then bank 1 would be the Passenger side O2 sensors.
If its sensor position 0 and 1, then sensor 1 would be the downstream O2 sensor, the one behind the Catalytic converter.


The ones behind the Catalytic converter are for checking the Catalytic Converter efficiency and operation, the "shouldn't" make the engine run rough. The upstream O2 sensors, closer to the engine, provide feedback for the Air Fuel ratio, malfunctions and bogus info from these sensors "can" cause the engine to run poorly.


As well, the code is for "High Voltage" at the sensor. That does NOT mean the sensor is bad, the wiring can be bad, a short or bad ground, a wire burned on the exhaust, etc, etc. So look over the wires closely and see if you see anything wrong and fix it before replacing the sensor. You could replace the sensor and get the same code back, cause the problem wasn't the sensor, it was because of a burned or shorted wired to the sensor.
 

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Discussion Starter #14 (Edited)
wow thanks so much mongo!


autozone printed out a paper for me and said its the pass side ahead of the converter.
but they have been wrong with just about everything else so far!
how can I confirm that code p1052 is this forward ,pass side oxygen sensor location?


of course if this is the one I have to change it looks like the hardest to get to!
 

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I have changed both upstream O2 sensors, the hardest part is getting the connectors disconnected. The connectors are wedged up in a place so hard to get to its near impossible to disconnect them.

Again the description of the code doesn't necessarily mean the O2 sensor is bad, its saying the voltage to the sensor is too high. That could be a short or wiring problem as well as an internal O2 sensor problem.
 

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Ok, I checked the FSM quick last night.


There is no reference to code P1052, that don't have all the codes in the FSM.


There is only reference to Bank 1 and Bank 2, no Bank 0. I didn't have the time to find a confirmation that Bank 1 is Driver's side or Bank 2 is Passenger side. But that is the universal standard for cars, you count left to right from the perspective of sitting in the Driver's seat, front bumper to rear bumper.


BUT, what really matter is what the scan tools reads out. The Scan Tool might report the driver/passenger bank as 0/1, or it might be 1/2. You have to read the scan tool and know how it works.


The Scan tool should have same convention for Front to Rear. So if the Scan Tool starts counting at 0, then O2 sensor 1 should be the rear O2 sensor behind the Catalytic Converter. If the scan tool starts counting at 1, then Bank 1 should be the Driver's side.


So Autozone tells you their scanner said O2 sensor Bank 1 / Sensor 1 or O2 sensor 1/1. And that is the Passenger side front O2 sensor? That doesn't make sense. The scan tool doesn't count Bank 0 and Bank 1, then Sensor 1 and Sensor 2?


Its either the Driver's side Front O2 sensor, or its Passenger side rear O2 sensor. Seeing how the Front O2 sensor would effect engine operation, and the rear sensor would just give bogus testing of the Catalytic Converter, I'd say the Driver's side Front O2 sensor is much more likely.


Eitherway, before you go through all the pain of replacing the O2 sensor, you might want to confirm exactly which sensor the scan tools are telling you.
 

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I just googled P1052 again, for a Jeep, the description I get is O2 sensor voltage to high (or too rich), Bank 2 Sensor 1.


That would be the Passenger side, forward O2 sensor. Forward as in front of the catalytic converter.
 

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Discussion Starter #18
thanks for putting so much time into this mongo!
he called me last nite to tell me that it was still running bad and the cel was still on and flashing on his way in to work yesterday.
when he got in it to leave last nite mysteriously the light went out and the key trick was telling him it is not in diagnostic mode anymore!
he is going to take this opportunity to run it through inspection this morning to try and get a good sticker.
ill keep you posted.
 
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