Camshaft sensor
Thread Starter
MBWorld God!
Joined: Jul 2010
Posts: 31,279
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From: on my way
2012 CLS63
Camshaft sensor
Hi crew, hope all your cars are doing well.
I did a search but didn't really find any good/helpful info.
Had a CEL pop up yesterday for something camshaft sensor related (P0343/p0341).
Hoping it's something simple like the sensor itself but you never know with these cars.
Have 84K on the ody and the car has been doing great otherwise. I really hope it isn't cam shaft adjusters as that could be $$$.
Anyone have any insight on this matter? Taking the car in on Friday, and have been driving it since yesterday.
Today the light turned itself off but I know the code was stored.
Stay cool out there
I did a search but didn't really find any good/helpful info.
Had a CEL pop up yesterday for something camshaft sensor related (P0343/p0341).
Hoping it's something simple like the sensor itself but you never know with these cars.
Have 84K on the ody and the car has been doing great otherwise. I really hope it isn't cam shaft adjusters as that could be $$$.
Anyone have any insight on this matter? Taking the car in on Friday, and have been driving it since yesterday.
Today the light turned itself off but I know the code was stored.
Stay cool out there
Last edited by hyperion667; Jul 29, 2025 at 02:47 PM.
Out Of Control!!
Joined: Apr 2019
Posts: 12,241
Likes: 6,909
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
-- Have you had these sensors renewed earlier or are they likely feeding oil into the harness?
-- There's a chance the timing issue is physically real.
-- How many miles on existing oil change of what type?
-- There's a chance the timing issue is physically real.
-- How many miles on existing oil change of what type?
Last edited by CaliBenzDriver; Jul 29, 2025 at 05:08 PM.
Out Of Control!!
Joined: Apr 2019
Posts: 12,241
Likes: 6,909
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
GUIDED INSPECTION LIST
That is 6kMi old Mob1 oil
It is now thin black oil with limited hydraulic pressure
Go ahead and physically test your intake VVT gears are still effectively locked or that Bk2 is now actively loose.
Inspect CPS for oil leaking into harness connectors in particular the exhaust sennsors.
Last edited by CaliBenzDriver; Jul 29, 2025 at 05:25 PM.
Thread Starter
MBWorld God!
Joined: Jul 2010
Posts: 31,279
Likes: 3,917
From: on my way
2012 CLS63
Looks like I'm getting all 4 sensors replaced....oil in the harness again too.....happened 7 years ago as well.
MY eco start/stop was disengaging itself right after I turn the car on which was apparently because of a weak battery.
I had a new battery installed 5 years ago so I opted out of replacing it now.
I was told the eco turning itself off would not be an issue.
Any advice or insight welcome
MY eco start/stop was disengaging itself right after I turn the car on which was apparently because of a weak battery.
I had a new battery installed 5 years ago so I opted out of replacing it now.
I was told the eco turning itself off would not be an issue.
Any advice or insight welcome
Out Of Control!!
Joined: Apr 2019
Posts: 12,241
Likes: 6,909
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
STANDARD STOCK COURSE
Looks like I'm getting all 4 sensors replaced....oil in the harness again too.....happened 7 years ago as well.
MY eco start/stop was disengaging itself right after I turn the car on which was apparently because of a weak battery.
I had a new battery installed 5 years ago so I opted out of replacing it now.
I was told the eco turning itself off would not be an issue.
Any advice or insight welcome
MY eco start/stop was disengaging itself right after I turn the car on which was apparently because of a weak battery.
I had a new battery installed 5 years ago so I opted out of replacing it now.
I was told the eco turning itself off would not be an issue.
Any advice or insight welcome
Did they do your engine oil too?
To keep ECO enabled it's best to keep best batteries on-board.
+++ IMPROVED ODDS...
Instead of 100% stock you could decide to experiment with :
- improved engine oiling
- Protection installed on leaky sensors
- extreme heatsoak tamed
- ECO disabled
- Batteries well charged
Last edited by CaliBenzDriver; Aug 2, 2025 at 01:56 AM.
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Thread Starter
MBWorld God!
Joined: Jul 2010
Posts: 31,279
Likes: 3,917
From: on my way
2012 CLS63
Indicator Light Concern - 'Eco' button light is turning itself off after starting the vehicle. Usually he will press the button to
turn it off, but it turns off before he has a chance too.
Function checked. Found ECO icon turns yellow when starting car, then goes away shortly after. Connected SDS. Ran quick test. No
immediate faults pertaining to issue. Checked through ECO start stop signals and noticed no issues. Researched condition and found
no bulletins or LI's, but did find through several relevant that early main battery failure can cause condition. Inspected battery. Found
dated August 2020. Performed battery test. Found battery at 80% capacity. Not immediately failing, but in order to restore ECO
function, will need replacement. Advise replacement of main systems battery.
Inspection and Testing
This was the message (from the shop) pertaining to the ECO button turning itself off right after startup.
turn it off, but it turns off before he has a chance too.
Function checked. Found ECO icon turns yellow when starting car, then goes away shortly after. Connected SDS. Ran quick test. No
immediate faults pertaining to issue. Checked through ECO start stop signals and noticed no issues. Researched condition and found
no bulletins or LI's, but did find through several relevant that early main battery failure can cause condition. Inspected battery. Found
dated August 2020. Performed battery test. Found battery at 80% capacity. Not immediately failing, but in order to restore ECO
function, will need replacement. Advise replacement of main systems battery.
Inspection and Testing
This was the message (from the shop) pertaining to the ECO button turning itself off right after startup.
Thread Starter
MBWorld God!
Joined: Jul 2010
Posts: 31,279
Likes: 3,917
From: on my way
2012 CLS63
BTW: this was the recommendation FOR THE cel.
Check Engine Light Concern - Light came on and vehicle has been driving fine. Found faults P0341 and P0343. Light turned
off for a few days, but just came back on today.
Connected SDS. Ran quick test. Found fault in engine control module for - P034300 The position sensor of the intake camshaft
(cylinder bank 1) has a short circuit to positive. _ - Removed connector to bank one intake cam position sensor and inspected.
Found that there is oil in harness, causing short. Advise disassembly of all accessible engine connectors, clean thoroughly,
including engine control module if affected, and replace all camshaft solenoid actuators.
Inspection and Testing
Check Engine Light Concern - Light came on and vehicle has been driving fine. Found faults P0341 and P0343. Light turned
off for a few days, but just came back on today.
Connected SDS. Ran quick test. Found fault in engine control module for - P034300 The position sensor of the intake camshaft
(cylinder bank 1) has a short circuit to positive. _ - Removed connector to bank one intake cam position sensor and inspected.
Found that there is oil in harness, causing short. Advise disassembly of all accessible engine connectors, clean thoroughly,
including engine control module if affected, and replace all camshaft solenoid actuators.
Inspection and Testing
Out Of Control!!
Joined: Apr 2019
Posts: 12,241
Likes: 6,909
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
ONE MORE ROUND....
BTW: this was the recommendation FOR THE cel.
Check Engine Light Concern - Light came on and vehicle has been driving fine. Found faults P0341 and P0343. Light turned
off for a few days, but just came back on today.
Connected SDS. Ran quick test. Found fault in engine control module for - P034300 The position sensor of the intake camshaft
(cylinder bank 1) has a short circuit to positive. _ - Removed connector to bank one intake cam position sensor and inspected.
Found that there is oil in harness, causing short. Advise disassembly of all accessible engine connectors, clean thoroughly,
including engine control module if affected, and replace all camshaft solenoid actuators.
Inspection and Testing
Check Engine Light Concern - Light came on and vehicle has been driving fine. Found faults P0341 and P0343. Light turned
off for a few days, but just came back on today.
Connected SDS. Ran quick test. Found fault in engine control module for - P034300 The position sensor of the intake camshaft
(cylinder bank 1) has a short circuit to positive. _ - Removed connector to bank one intake cam position sensor and inspected.
Found that there is oil in harness, causing short. Advise disassembly of all accessible engine connectors, clean thoroughly,
including engine control module if affected, and replace all camshaft solenoid actuators.
Inspection and Testing
Your engine extreme heat soaks worsened by ECO cycles has compromise your camshaft sensors. This is the famous "$10k oily-harness" repair.
The engine harness is now re-filled with oil as witnessed by CEL investigation.
This was repaired once already without solving the cause. So the same breached sensors have recreated the same issue.
Sacrificial pigtail are only a band-aid protection.
An experimental solution would be to disable extreme heat soaks from dry piston accumulating heat.
Last edited by CaliBenzDriver; Aug 4, 2025 at 12:13 PM.
