SL/R231: ECU programing / oil in wires etc
Thread Starter
Junior Member
Joined: Apr 2015
Posts: 36
Likes: 4
2003 SL55 / 2013 SL550
ECU programing / oil in wires etc
Hi,
First got a check engine saying camshaft position sensor circuit low.. Shop replaced sensor and magnets, next day I get a new check engine saying camshaft position sensor is now high... mechanic said wiring has oil and maybe oil invECU, but I am not 100% certain.
First, any thoughts on this? Camshaft sensor replaced wrong or was never bad in the first place?
If oil in wires... Would it be all the wires under the hood, or only the wires coming from camshaft sensor? Can you just replace those wires?
Mercedes has pigtails to add to camshaft sensors to I guess stop it from happening again... but if there is oil in the harness now, is it just trashed, or if you clean it up and place the pigtails, will it be okay?
If the ECU is bad, I see used ones for 200-300, I believe you have to copy the files from the old and clone them onto the replacement.
I saw a video where someone used Hexprog to do it, but it has a subscription and have to pay every time you use it.
Is it the best progrmamer out there? any other recommendations?
Years ago I saw a guy on here selling software/ computer to work on mercedes, supposed to be like the ones the dealers use. Is he still around? Can you close with that software?
Car is a 2013 SL550 with 130k miles, I love it... but scared now of electrical demons. Any advice is appreciated!
First got a check engine saying camshaft position sensor circuit low.. Shop replaced sensor and magnets, next day I get a new check engine saying camshaft position sensor is now high... mechanic said wiring has oil and maybe oil invECU, but I am not 100% certain.
First, any thoughts on this? Camshaft sensor replaced wrong or was never bad in the first place?
If oil in wires... Would it be all the wires under the hood, or only the wires coming from camshaft sensor? Can you just replace those wires?
Mercedes has pigtails to add to camshaft sensors to I guess stop it from happening again... but if there is oil in the harness now, is it just trashed, or if you clean it up and place the pigtails, will it be okay?
If the ECU is bad, I see used ones for 200-300, I believe you have to copy the files from the old and clone them onto the replacement.
I saw a video where someone used Hexprog to do it, but it has a subscription and have to pay every time you use it.
Is it the best progrmamer out there? any other recommendations?
Years ago I saw a guy on here selling software/ computer to work on mercedes, supposed to be like the ones the dealers use. Is he still around? Can you close with that software?
Car is a 2013 SL550 with 130k miles, I love it... but scared now of electrical demons. Any advice is appreciated!
MBWorld Fanatic!
Joined: Feb 2021
Posts: 1,419
Likes: 739
From: Nor-Cal
2020 GLC300 -2014 Sl550 - 1997 SL600
Hi,
What code was triggered?
Did they find oil when they replaced them?
You usually can see oil on the pins and/or connectors.
doubtful
possible
no
Yes most likely if they actually found oil in the wires.
Probably not if it’s traveled to the ECU. You can try electrical cleaner. Sometimes that works.
Depends on if you can get the oil out of the harness. If it’s made it to the ECU that could be a problem.
Yes
Do some research, there are some on MBworld. There are several competent programmers on this site. I’ve never hade to use any of them so have no recommendations.
Good Luck.
What code was triggered?
Did they find oil when they replaced them?
You usually can see oil on the pins and/or connectors.
doubtful
possible
no
Yes most likely if they actually found oil in the wires.
Probably not if it’s traveled to the ECU. You can try electrical cleaner. Sometimes that works.
Depends on if you can get the oil out of the harness. If it’s made it to the ECU that could be a problem.
Yes
Do some research, there are some on MBworld. There are several competent programmers on this site. I’ve never hade to use any of them so have no recommendations.
Good Luck.
Last edited by crconsulting; Oct 24, 2025 at 06:47 PM.
Member
Joined: Jun 2007
Posts: 81
Likes: 7
From: New York
E450 coupe 2021 SL550 2013
I had that problem on my SL 550. Sensors fail like that commonly, and the oil wicks up the wires. Inexpensive to replace the sensors. You can replace the wires but you have to remove the engine to do it. The wires are routed in a way so that it cannot be done otherwise. It was quoted at $8000.00 from the dealer to do the job. If the oil got to the circuit board you have to replace that too. I had 100k miles on the car at the time and elected to get a new car. If you decide to replace those parts then while the engine is out i would replace the engine mounts at the same time.
MBWorld Fanatic!
Joined: Feb 2021
Posts: 1,419
Likes: 739
From: Nor-Cal
2020 GLC300 -2014 Sl550 - 1997 SL600
I check those sensors regularly, once a year or so. Any car that still has the old ones, should probably be replaced with the new design, and add the wiring pigtails.
But the new design has held up in all the cars I’ve installed them in. (So far!)
Good Luck
But the new design has held up in all the cars I’ve installed them in. (So far!)
Good Luck
Last edited by crconsulting; Oct 25, 2025 at 05:03 PM.
