ECU Repair or Cloning?
Thread Starter
Newbie
Joined: Jun 2021
Posts: 6
Likes: 0
E320
ECU Repair or Cloning?
Hi All,
My local mechanic diagnosed a bad ECU on my 2004 E320. Issue is the ECU is not sending the ground signal to the charcoal canister vent valve. When the mechanic diagnosed it, they send the command to close the vent valve, their computer said the command was sent, but the vent valve didn't close. I verified the vent valve is good and I also checked the wiring by introducing ground at the ECU and it closed the valve.
I sent the ECU out for repair and was told the ECU was fixed and it had a hardware issue. Not sure what was done, but I still have the issue.
Short of going to the dealer, what are my options? Trying another repair service? Anyone have luck with cloning to a good ECU? Would appreciate any feedback or options!
Thanks,
Jamie
My local mechanic diagnosed a bad ECU on my 2004 E320. Issue is the ECU is not sending the ground signal to the charcoal canister vent valve. When the mechanic diagnosed it, they send the command to close the vent valve, their computer said the command was sent, but the vent valve didn't close. I verified the vent valve is good and I also checked the wiring by introducing ground at the ECU and it closed the valve.
I sent the ECU out for repair and was told the ECU was fixed and it had a hardware issue. Not sure what was done, but I still have the issue.
Short of going to the dealer, what are my options? Trying another repair service? Anyone have luck with cloning to a good ECU? Would appreciate any feedback or options!
Thanks,
Jamie
MBWorld Fanatic!
Joined: Jul 2012
Posts: 4,514
Likes: 1,513
From: Orbiting the planet
This place is a joke.
I've never seen an ECU repair service work for these cars. Try reversing the wire at the shutoff valve or buy the adapter harness that does. This has been an ongoing problem with the replacement valve.
MBWorld Fanatic!
Joined: May 2017
Posts: 2,290
Likes: 434
C320
Is this a smog check or emissions testing issue? If yes, fill up the fuel tank, reset the codes in the ECU and keep driving it until the other readiness monitors go away. Keep refilling the tank before the 3/4 mark until you smog it. The evap monitor complete is NOT required for smog check but evap monitor will trigger CEL if fuel level drops below 3/4. Smog the car as soon as all the other monitors clear. That's how I got my C320 through smog. CEL will trigger again as soon as fuel level drops below 3/4. I just live with it and go through this process once every 2 years. Not worth the trouble of replacing the ECU.
Last edited by tjts1; Sep 27, 2021 at 06:37 PM.
Thread Starter
Newbie
Joined: Jun 2021
Posts: 6
Likes: 0
E320
Thanks for the quick replies.
I will try reversing the wires, but I had the issue before replacing the valve and before the new harness. I tapped into the ground wire at the ECU and ran a jumper to a good ground. That activated the vent valve.
I'm not worried about passing inspection, I have time for that. The issue is when I get the stupid 'check gas cap' error and it doesn't go away until I restart. When it goes off, it beeps every time I take off from a start. Then it throws a P0455.
I will try reversing the wires, but I had the issue before replacing the valve and before the new harness. I tapped into the ground wire at the ECU and ran a jumper to a good ground. That activated the vent valve.
I'm not worried about passing inspection, I have time for that. The issue is when I get the stupid 'check gas cap' error and it doesn't go away until I restart. When it goes off, it beeps every time I take off from a start. Then it throws a P0455.
Newbie
Joined: Jul 2019
Posts: 11
Likes: 0
From: New England
E430, C320(2004)
ECU upload issue
Is this a smog check or emissions testing issue? If yes, fill up the fuel tank, reset the codes in the ECU and keep driving it until the other readiness monitors go away. Keep refilling the tank before the 3/4 mark until you smog it. The evap monitor complete is NOT required for smog check but evap monitor will trigger CEL if fuel level drops below 3/4. Smog the car as soon as all the other monitors clear. That's how I got my C320 through smog. CEL will trigger again as soon as fuel level drops below 3/4. I just live with it and go through this process once every 2 years. Not worth the trouble of replacing the ECU.
Robert
