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2001 E320 Wagon 4 Matic
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Discussion Starter #1
Last week I cleared a CEL code with my generic code reader and it showed monitoring after that. It is time to SMOG the car (CA) by this week end and I know that if it shows monitoring it will not pass smog. So today and plugged the reader in to check and now it will not not connect data with the ccar. It plugs in and feels just like normal, but does not connect to transmit data.
I checked the reader on my other car (Prius) and it works fine on that car, I even changed batteries in the reader to make sure - no connecting to ECU on MB still... I have used this reader for years without issues including on this 2001 E320 Wagon.

So, the reader is not the issue. I have searched here and elsewhere and some people have had similar experiences due to blown or missing fuse. Well, the fuse can't be missing since I have never removed it and it worked last week with the reader. I can not find a fuse for the ODB port, I see comments on a K40 module and a 7.5 amp fuse there...Well, not sure where the K40 module is, but it seems like it must be the area next to the main fuse box in the engine bay / driver side fender - the one that you have to unscrew to get under the lid and containing a few fuses and relays. Would this be the right place? I saw a couple of pictures, but it didn't look like on my car..

Well, I checked all fuses there and in the general fuse area next to it, and the small fuse area on left side of dash by driver door and fuse area under the back seat by battery. So I have checked all those fuses in those areas, and no fuses are blown.

Is there another area / fuse somewhere that I am missing? When I look at the fuse diagrams, there is no fuse listed for ODB or Diagnostic port or anything similar.....
I guess if no blown fuse present, I'll have to crawl under the panel where the port is to see if a wire is loose or something.
Strange to say the least...

Any other ideas? I know I can definitely not SMOG the car if the mechanic can not get the readings from ECU, so I got to find a solution somehow..and any ideas would be gratefully accepted.

Thank You!
 

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Premium Member
1998 E320 base sedan @ 160kmiles
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6,368 Posts
The 7.5 amp fuse is on the K40/4 module, which is at the passenger side under the module box lid. Bear the firewall at the passenger side under the hood, you see a lid with 4 screws. You remove the lid, and you will see the K40 module which is closest to the front. The 7.5 amp fuse is the fuse on the right.
 

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2001 E320 Wagon 4 Matic
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8 Posts
Discussion Starter #3
The 7.5 amp fuse is on the K40/4 module, which is at the passenger side under the module box lid. Bear the firewall at the passenger side under the hood, you see a lid with 4 screws. You remove the lid, and you will see the K40 module which is closest to the front. The 7.5 amp fuse is the fuse on the right.
Great, thank you, will have another look under the hood to see if I can locate it! Will report back.
 

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2001 E320 Wagon 4 Matic
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Discussion Starter #4
Opened up the K40 module, found the fuses, pulled and inspected all and none were blown. I replaced the 7.5 amp fuse anyway but still no communication with my reader. I also pulled the OBD port from the panel and inspected the wires and they were connected, made sure they were seated in OBD connector. No change. What surprises me was that were only 4 wires there, but no other loose or disconnected on the side or anything....Two brown, one Black/white and one Red/white - that's it!
So I am at loss here and will probably bring in the car to a good independent MB shop tomorrow to see if they can figure it out, unless I or somebody else here get some brilliant idea before the morning....
 

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Outstanding Contributor , SDS Guru
1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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Stupid question, but have you actually tried to leave key in position 2 before trying to read with the scanner?
 

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1998 E320 base sedan @ 160kmiles
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Red/white wire is the 12V, and the brown wires are the grounds, so you can connect a multimeter to measure that you get the power to the connector. The Black/white wire is signaling wire (pin 7). You should also check the voltage on 7.5 amp fuse which should be at 12V (always-on).
 

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Outstanding Contributor , SDS Guru
1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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3,667 Posts
And you have power to your scanner? It lights up the moment you plug it in?

Have you tried with engine running?
 

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Outstanding Contributor , SDS Guru
1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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3,667 Posts
Well.....then most likely it's a wiring issue.

I'd check the pins on your OBD port, and then the pins on your scanner.
 

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2002 Mercedes ML320, Mercedes 190E 2.3L (sold), 2001 Mercedes c320(gone)
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1,454 Posts
One thing... Can you connect to other modules or is this a general no communication issue between scanner and car...

Sent from my PH-1 using Tapatalk
 

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Premium Member
1998 E320 base sedan @ 160kmiles
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6,368 Posts
One thing... Can you connect to other modules or is this a general no communication issue between scanner and car...

Sent from my PH-1 using Tapatalk
Not from the OBD2 port. Only the ECU can be accessed from this port for this model year.
 

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2001 E320 Wagon 4 Matic
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Discussion Starter #14
UPDATE:
Well I took the car to the independent MB shop and it scanned with their scanner and showed still pending monitors. The CATS were bad, no way around it - 3 out of 4! I guess not surprising with 277K miles on it...A good muffler shop I have used before with good results installed them for $1100, a lot better than $2400 (with pipes mind you) at the dealer.
A lot of cash to repair a 20 year old car, but I bought it from the original owner six years ago and it's been a great car - so planning to hold on to it a few more years.

SMOG will be the next few days, hopefully without issue, I'll go back to muffler shop for a scan read of monitors before.

The scanner is still a mystery, double checked all pins on it and USB port connector (well, the port works with at the shops) but found no issues and it still works with my other car. Strange it is for sure....Thinking of getting another cable maybe or finding a laptop based software for scanning instead..anyone used a good one of those?
I have a OBD2 to USB cable that I have used on my motorcycle for ECUtune and software to tune it's ECU.
But it's not a scanner, just a cable, not sure if that works with just it and a software, would the scanner function be in the software on the laptop? I have seen something called TOAD that connects with a device called ELM327.
 

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Outstanding Contributor , SDS Guru
1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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Depends on what that OBD to USB interface hardware is. There are some free software that can use the interface to read generic OBD codes and pull monitor readiness. I think its called ScanXL?


Not sure which one is free, I got it for free when I bought my equipment from one of my vendors....
 

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2001 E320 Wagon 4 Matic
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Discussion Starter #16

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2001 E320 Wagon 4 Matic
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8 Posts
Discussion Starter #18

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2002 Mercedes ML320, Mercedes 190E 2.3L (sold), 2001 Mercedes c320(gone)
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1,454 Posts
Get a bluetooth or USB or wi-fi OBD2 device and use tghe appropriate program. I use BAFX bluetooth and Torque-Pro.
https://www.amazon.com/BAFX-Products-Wireless-Bluetooth-Diagnostic/dp/B005NLQAHS

This is something you can permanently install, and monitor the real time data with your android phone for bluetooth, or Iphone with wi-fi version.
@mrboca do you leave your bafx device permanently connected? I have this paranoia about leaving mine even though I know the current draw will be very very small...

I use palmerperformance's dashcommand premium.

Sent from my PH-1 using Tapatalk
 

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1998 E320 base sedan @ 160kmiles
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When I do not use it for my other cars. yes. I do not know the exact current draw when idle, but assuming 50 millamps, for 10 hours , it will reduce the capacity 0.5 ampere-hours which is negligible. It is my son's daily driver, and gets 50 highway miles of charging a day. So the battery is topped-up in no time.

If I do not use the car for extended periods of time, I would remove it, and also put the battery on battery maintainer.
 
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