My check engine light just came on and I get code p0456 in my 2005 hemi dodge magnum. A day before the check engine light came on, I had changed my air filter, after which I noticed a howling sound coming from near that area. The howl is most noticeable right when I turn the car on and at very low speeds. The howl is pretty much unnoticeable at 40 mph and higher. I have reseated the air filter a few times and checked for cracked hoses and I am not seeing anything. I am in desperate need for some advice from a guru!

 

The code and the noise may be two separate issues. P0456 - EVAP PURGE SYSTEM SMALL LEAK.

Check your gas cap. A loose cap can set this code.


As for the noise, check the PVC line where it goes into the air tube. I also believe there is an air sensor that also plugs into the air tube. It sounds like something got knocked loose or disconnected when you changed your filter. You might take a very close look at the air filter and make sure it seats properly and does not have a slight warp or small flaw at any of the edges where it seals that may be causing a leak.

 

Thanks for the response! I still have the old air filter, so I will try starting the car with that one tomorrow and see if I get the howling noise, and if I do, I will check the other things you said to check.

Also, I should have mentioned, that I have two error codes. p0457 and p0456 in that order. The gas cap was definitely loose and I resealed it about 5 days ago. I did not reset the codes because I wanted to see if the CEL would turn off on it's own. The light is still on and I still have both codes. Is it ok for me to clear the codes out?

PS I am an amateur hobbyist when it comes to working on cars, I just really enjoy it!

 

the p0457 code was not in the service manual but with some searching I found this:

TSB#: 14-001-06

Date: January 21, 2006

Subject: Loose Fuel Cap Message or MIL Illumination for Diagnostic Trouble Code P0457 - EVAP System - Loose Fuel Cap

Models: 2006 300/Magnum/Charger

NOTE: This bulletin applies to all vehicles equipped with a gasoline engine.

NOTE: Do not replace the gas cap if only DTC P0457 - Evap System - Loose Fuel Cap is present.

Discussion: Starting with the introduction of 2005 model year vehicles a new diagnostic trouble code (DTC) P0457 - Evap System - Loose Fuel Cap was introduced. Also added to some vehicles was an instrument cluster message in the odometer display or message center (EVIC) that alerts the driver that the gas cap is loose.

The PCM monitors the fuel level for a "significant" change in either direction and remembers that this has recently occurred. A loose fuel cap DTC, cluster message or message center message matures when the check for the EVAP system large leak condition fails after the fuel level change event. If a leak of greater than 0.090" is observed after a fuel level change, a loose cap diagnostic single trip failure is stored and the cluster message or message center message is displayed even though a DTC may not yet be present. DTC P0457 - Evap System - Loose Fuel Cap is stored and the MIL illuminated after 2 cold start failures of the large leak diagnostic checks following a fuel change event. Only the passing of one of the 3 EVAP system diagnostic routines large leak, small leak or loose gas cap) by the PCM will validate that the cap is no longer loose and turn off the MIL light or message.

For 2007 model vehicles DTC P0457 - Evap System - Loose Fuel Cap will be stored and the MIL illuminated after 3 cold starts.

To temporarily clear the gas cap loose message from the odometer or message center press the reset button on the odometer or message center while the message is being displayed. This clears the message for the current key cycle only.

NOTE: The above works for all vehicles except, 2005 - 2006 Grand Cherokee or Commander. For these, the scantool must be used.

To clear the gas cap loose message from the odometer or message center ensure the gas cap is tight and let the vehicle run the small leak diagnostic routine. The small leak diagnostic routine will pass a sealed system after an 8 hour soak and a negative 3° C change in fuel temperature from the last key cycle.

NOTE: A heated garage may effect the small leak diagnostic routine. To clear the gas cap loose message from the odometer or message center and matured DTC (MIL light) diagnose and repair the leak and then erase DTC's with the DRB III®/StarSCAN™ scantool

NOTE: The DRB III®/StarSCAN™ scantool may be used to reset the Loose Cap message. Select the PCM Reset function on StarSCAN™ (version 6.05_SP1 or higher) or the Clear PCM Batt Disconnect function on DRB III®.
Disconnecting and reconnecting the battery will also clear the message.

If a gas cap loose message is displayed or DTC P0457 - Evap System - Loose Fuel Cap is set without P0455 - Evap System Large Leak then ensure the gas cap it tight, no further service action is required.

If you have a scantool I would go ahead and reset/clear the codes.

 

Thanks again for the help, I really do appreciate it.

I do have a scantool that will clear the codes out. If I reset the codes and the gas cap was not the reason for p0456, will the CEL come back on?

 

If the loose gas cap was NOT what tripped the code, it should come back. Then further investigation will be needed on the evap system. Hopefully this will not be the case.

 

So I reset the codes and have driven about 50 miles since, and the light has not come back on, so hopefully it was just the gas cap.

I reconnected the air sensor that plugs into the air tube and I tried the old air filter, and I still have the same howling noise. I was unable to find the PVC line that goes into the air tube. I only see the air sensor that plugs into the air tube.

The wife drove it to work today which is only a 10 minute drive and when she was pulling in the driveway, I heard a squealing noise. I popped the hood to take a listen and it is coming from the serpentine belt. The belt looks pretty new (I just bought this car from a private seller) and so do some of the pulleys. Also the magnum hasn't been driven in a couple of days, just sitting in the garage. Since then it has gotten 20 degrees colder. It also snowed a good 2-3 inches while the car was parked outside at where my wife works. Could this just be weather related or possibly moisture getting on the belt?

Thanks in advance!

 

A squealing belt could be weather related, or it could be loose. If the belt and some of the pulley's are really new, could have been the belt broke at one time, maybe the tensioner seized up or one of the belt driven devices. How closely have you check this howling? Could it be a bearing in the alternator or something like that, maybe something that was damaged if the belt had broken previously. You might want to get an automotive stethoscope (Harbor Freight, Northern Tool, Autozone, etc $4 and up) to help pinpoint your mystery noises. There is only so much intake between the throttle body and the air filter to have a leak, and if the noise is coming from the intake area, it could be from another source. I assume that you have removed the plastic cover from the engine while you have been doing all this checking? Dumb question but I knew one fella that didn't and missed a disconnected vacuum hose under the cover.

 

Yeah, I removed the plastic cover from the engine and I don't see anything loose. I will go get one of those stethoscopes to help pinpoint the problem.

I did notice that the power steering pump pulley has some play in it, but I don't see how to tighten it. I am guessing it is a press fit. Is there anyway I can do this from home or do I need a special tool?