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2007 E63 AMG Estate, 2000 E430 Avatngarde Estate
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18 Posts
Discussion Starter #1
Hi,

At idle, a valve or relay of some sorts ticks for a while, then stops for a while, then ticks again (you get the picture).

Here's a couple of pictures of it, apologies for the quality, they are from my phone.




It's mounted on the passenger side inner wing next to the ABS pump.

What is it, what does it do, I've been told it is normal to make this noise, but it has never done it in the past, so why now? Is it the cold weather? Will a new one make this noise?

Many thanks
 

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Dallas, Texas
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7,764 Posts
This is purge control valve. It was ticking when car left production line. When is stops ticking CEL will illuminate.

You may be hearing it more in cold weather because its rubber mount has hardened.
 

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2007 E63 AMG Estate, 2000 E430 Avatngarde Estate
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Discussion Starter #3
Thanks for that.

You might be right regarding the rubber mounting, we've been having snow and -4deg C temps over here at the moment.

Reading your attachement it says it activates when purge is detected, so would this explain why it doesn't "click" all the time? and what is purge?
 

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1999 E55, 2001 E320, 1990 560 SEC, 2004 ML350, 2001 ML55, 1995 S500, 1998 SL500, 2010 E550 Sport zoo
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7,035 Posts
If you want you can clean the purge control valve with MAF cleaner - seems to tick a bit less - sort of like a car running "better" after a oil change, could be psychological or could be real.
 

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'01-E320 & 02-ST2
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31,631 Posts
Whew! Crisis averted! For a moment I thought there was another one to be concerned about...
but no, it's already covered in the stickies. :rolleyes:
 

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1994 SL500 imperial red
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118 Posts
Hi all ... I have the above click, so phew not a problem, but i also a clicking from the front of the enging.
Have searched he site and web, but not found too much.
Anyone got any pointers?
Thx
 

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'01-E320 & 02-ST2
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Hi all ... I have the above click, so phew not a problem, but i also a clicking from the front of the enging.
Have searched he site and web, but not found too much.
Anyone got any pointers?
Thx
Easiest thing to do:

Engine cold, remove the serpentine belt (be sure you have a diagram, there is one in the owner's manual and also posted on the site, or you can make one).

Spin and test for free play all accessory pulleys. Note any that are suspicious. Pay extra attention to the idler pulley and tensioner pulley/assembly.

Leave the hood up and start the engine (belt still off). You will have a few warning lights but those can be ignored.

Stick your head under the hood and see if your noise is gone.

Turn off the car and with the key back in your pocket reinstall the serpentine belt.

If the noise was gone with the belt off, then you know it's one of those accessories. Replace as necessary.

Good luck.
 

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1994 SL500 imperial red
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118 Posts
Easiest thing to do:

Engine cold, remove the serpentine belt (be sure you have a diagram, there is one in the owner's manual and also posted on the site, or you can make one).

Spin and test for free play all accessory pulleys. Note any that are suspicious. Pay extra attention to the idler pulley and tensioner pulley/assembly.

Leave the hood up and start the engine (belt still off). You will have a few warning lights but those can be ignored.

Stick your head under the hood and see if your noise is gone.

Turn off the car and with the key back in your pocket reinstall the serpentine belt.

If the noise was gone with the belt off, then you know it's one of those accessories. Replace as necessary.

Good luck.
Great stuff .... Thanks for the tip. Shall give it a go this wekend or next.
Sorry for slow reply .... Didnt get a reply notification. Appreciate the help!
 

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1998 e320 4matic wagon
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46 Posts
P0446 evap code, no ticking from purge valve

hi, (1998 e320 wagaon 4m)
I used to have the clicking from the purge valve, but now i don't hear/feel it. i only realized it when i started researching a P0446 evaporative emission system vent control circuit code (with the check engine electronics warning). i replaced the fuel cap (note: i see gas on the rubber gasket inside the cap...normal?) and reset the code, but it came back.

the rubber connections in/out of the purge valve look fine to my eye. i visually inspected the charcoal canister and vent control valve and surrounding tubes and didn't notice anything obviously suspicious. i disconnected and reconnected the harnesses on each valve (they appeared clean). i have not reset the code again.

i attached the freeze frame data from Launch car code reader 6001. i'm not sure what to look for there.

any thoughts?

thanks
Scott
 

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Premium Member
1998 E320 base sedan @ 160kmiles
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6,720 Posts
Hello:)

P0446 is primarily for the charcoal canister shutoff valve. If you had a purge valve issue, you would have likely had P0440 to P0443.

You need to check if the shut off valve actually gets 12V.
 

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1998 e320 4matic wagon
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46 Posts
thanks mrboca. i'll do that this week and report back. would you please confirm the steps and contact points to verify the voltage at the shut-off valve? i am new to using a multi-meter (ordering one on amazon today....any recommendations?).

Scott
 

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1998 E320 base sedan @ 160kmiles
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Well, since you are new to multimeters, you need a good starter one which is reasonably priced. I could recommend Fluke but why pay so much money if you do not use it all the time ?

I have a Fluke but it is for indoor use only :) For garage rudimentary measurements, I actually use free Harbor Freight ones :) I do not care if they get dirty, as long as they do the job :).

Here is one that you can use. It is auto ranging so much easier for you. Back-lit, and if the frequency measurement works as advertised, it would be very handy. Also the alligator clips will be useful to keep your hands free.

https://www.amazon.com/Neoteck-Multimeter-Multimeters-Resistance-Transistor/dp/B01NAVAT9S/ref=cm_cr_arp_d_product_top?ie=UTF8

If you already know where the shut off valve is, you would need to take the connector out and measure 12V between chassis ground and the connection where the red/green wire is terminated.. You need to put the ignition key to position 2 (with all dashboard lights on).

You may have a bad cut-off valve, vacuum issue, or any other issues in the logic chain but we need to start from somewhere :)

Also, you do not overfill your gas tank, do you ? :)
 

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1998 e320 4matic wagon
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46 Posts
Excellent....the multimeter is on its way!

the shut off valve sits right on top of the charcoal canister with the electrical connection on top, right?. i was looking around for any visual issues and disconnected and reconnected it.

I never fill past the natural stopping point, but in NJ they don't let us pump our own gas, so i'm sure the attendants fill beyond that. i'll warn them not to going forward.
 

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1998 e320 4matic wagon
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46 Posts
I tried testing the voltage at the shutoff valve with the key turned to the position with dash lights on, but not started. help me confirm i'm doing this correctly. i grounded to the chassis and tested the positive lead on each of the 2 pins at the end of the harness that connects to the valve (white, round plastic part on top of the charcoal canister). one pin gave me an unstable reading and the other settled at about 2.6v.

note: i checked my battery and it was charged at 12.5v and showed 13.8v when charging with the engine running.

did i perform the test properly?

thanks,
S
 

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Premium Member
1998 E320 base sedan @ 160kmiles
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6,720 Posts
If you measured the battery voltage with your new meter, you then know how to measure voltage correctly :)

All 4 oxygen sensor heater circuits, purge valve, shut off valve receive 12 V power from the same source (through the polarity reversal relay in the K40 relay module at the passenger side).

So one pin of each of the above should read 12V (remove the connector, and check the voltage at the terminals of the connector, not at the unplugged device:) WHEN THE IGNITION KEY IS TURNED TO "RUN" OR POSITION 2. The other pin of each of the above typically float when not activated by the engine computer. The ECU applies ground when required, and the O2 heaters, purge valve, shut off valve operate independently.

I assume you do not have any fault codes from your O2 sensors. Only P0446. This would mean that the O2 sensors receive 12V, but the shut off valve does not (if you measured properly). The black probe of the meter goes to the chassis metalwork (preferably a post where the ground wires are bolted on), and the red probe goes to where you need the voltage measured.

You could do the same measurement at the purge valve to check if the purge valve receives 12V with the key in position 2.

Have you got any electrical work done on your car sir ? O2 sensors maybe ? K40 relay wiring ? This 12V supply circuit goes out of K40 relay module as a single wire and at some point it goes into a distribution point (Z7/39) to fan out to 6 wires (4 O2 sensor heaters, shut of and purge valves).
 

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1998 e320 4matic wagon
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46 Posts
Mr Boca, i appreciate your working with me on this.

i just tested the purge valve wire and saw 12.21v on one side of the socket (on the wire to the valve, not the valve itself) and 5.45v on the other. both were stable. i used the ground post near the positive battery post under the hood right by the purge valve. is it possible that i didn't get a good ground when testing the the vent valve (it took a while to settle at 2.6v on one side and the other never settled).

i don't have any other codes. should i bother to test the voltage at the o2 sensors?

the only work done on the vehicle recently was replacement of the driver's door and the seat switch is not fully working.
i can't imagine that's related, but the symptoms are: the seat back knob doesn't move the seat, but the preset buttons (2 of the 3 work, one doesn't) move all parts of the seat. also, i can't set the memory on the 2 working presets.

Scott
 

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1998 E320 base sedan @ 160kmiles
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It is possible. Since you have a known "good" ground (the post near the purge valve), I would just extend the connection and use it for the ground reference. You have the alligator lead that came with the meter, don't you ?:) Just use some wire extension to the meter black probe and measure voltage on the the red/green wire from the harness to the valve. Brown/red wire goes to the ECU. The wire colors may be different though. I had seen a blue color wire for 12V to shut off valve too. In any case measure both with a known good ground.

Regarding the door control problems, it is likely that you have a bad door control switch unit (the part you move), as the switch activation recognition is done by voltage coding to a single input to the door control module. So, say seat back is 4V, seat forward is 6V seat up is 8V seat down is 10 V, etc. etc. (not real figures, just to illustrate how it works). Each switch has a specific resistor in series, to determine the voltage level.
 

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1998 e320 4matic wagon
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46 Posts
great idea! i'm getting good at removing that liner without removing the wheel. with the extension wire to the known good ground, i see 12.05v and 5.4v on the pins of the wire to the shutoff valve. sounds like power is getting there and suspicion goes the the valve itself? how do i confirm that? or maybe i am jumping the gun....

Scott
 

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1998 E320 base sedan @ 160kmiles
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6,720 Posts
OK, Voltage supply test passed. The next step is to measure the current through the valve solenoid, which means you need to put the meter in "current" mode, and plug the probes in the socket for current reading, and connect the meter in series. I know this is difficult without some sort of "adapter" plug, or wire cutting, so another way is to test the resistance between the pins of the valve.

The spec calls for 0.5 to 0.9 amp current draw when the valve is activated, so the resistance should be 15 to 30 ohms range (allowing some source resistance). If you have a high resistance then you have an open circuit in the device or its connector. Set the meter to resistance, and measure the resistance between the valve pins.

The part is between $160 to $220 depending on where you buy, so, a failure confirmation would make sense (at least to me :).
 
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