I have a Mercedes with gave me the following codes:
1208 Constant Adjustment Of Intake Camshaft Of Right Cylinder Bank In Direction ‘Retarded'(P0016)
Stored
0745 Self-adaptation Of Mixture Formation For Enrichment At Idle For The Right Cylinder Bank Is Above The Permissible Limit. (P0171) Current and stored
0749 Self-adaptation Of Mixture Formation For Enrichment At Idle For The Left Cylinder Bank Is Above The Permissible Limit. (P0174) Stored
0810 Malfunction Of Secondary Air Injection At Right Bank Of Cylinders(Function chain)(P0410)
Current and stored
0814 Malfunction Of Secondary Air Injection At Left Bank Of Cylinders(Function chain)(P0410)
Current and stored
0732 Continuous Camshaft Adjustment( RIGHT ): Incorrect Position Of The Exhaust camshaft(P0014)
Stored
0736 Continuous Camshaft Adjustment( LEFT ): Incorrect Position Of The Exhaust camshaft(P0024)
Stored
I use a scope to check the cam and all camshafts sensors. I do suspect that the timing chain is worn but to make sure I use the scope to confirm it. If you look at the image below you will notice that only one cam line up and that is the r/h intake cam. The cam’s wave must line up with the red line when it goes up or at the beginning when the sensor and the sensor plate meets.
The chain is connected to both left and right intake adjuster, and via gear train to the exhaust adjuster. If base timing is off on the intake, then base timing is off on the exhaust cams as well. I am going to this job soon to correct this problem then I will update the results.
Well the job was done and no more codes and the car is running perfectly, but I must warn you, you have to make sure that the chain timing marks are correct.
Peter, this site doesn’t have mail notification feature and thus we both are kind of late to each other. Guilty party here.
Nonetheless, I really appreciate your comments, answers. And you might be right: I am getting 1208 more and more often :(.
Now, here is my question: at idle, my intake is 36 degree advanced (max) while exhaust is -20 degree retarded (min by design). Under load, intake lower to 0-20 degree and exhaust increase to 10-20 degree to provide more torque—also great as expected. Problem is: when I take off the gas pedal, intake going back to 36 degree but somehow might go overboard a bit to 36.2 (which is not that unusual for both left and right bank). But then, all of a sudden, variable valve timing became fixed—meaning it sticks at 36.2 degree and not fluctuating anymore! Which part went wrong, will a waveform like you did answer that question?
Thank you!
Hi that waveform will help especially to check it while you are driving, maybe if you have a scope backprope the suspect cam solenoid and see if you get control from PCM when it becomes fixed. If you get control from the PCM but the cam is not advancing or retarding like the other intake cam (you have to connect a scanner to check both intake cams operations). I would check the solenoid condition, remove it and clean it and connect 12v to the connections and see if you hear any clicking, but in some cases, it is better to replace it. It is not a very expensive part, the other day I had one that looks good but when it comes that it must operate properly it failed. So after replacing the solenoid the problem was fixed. You can also swap the solenoids to see if the problem moves with the solenoid if not then you have to look at the vvt and chain.
Hi that waveform will help especially to check it while you are driving,
maybe if you have a scope backprope the suspect cam solenoid and see if
you get control from PCM when it becomes fixed. If you get control from
the PCM but the cam is not advancing or retarding like the other intake
cam (you have to connect a scanner to check both intake cams
operations). I would check the solenoid condition, remove it and clean
it and connect 12v to the connections and see if you hear any clicking,
but in some cases, it is better to replace it. It is not a very
expensive part, the other day I had one that looks good but when it
comes that it must operate properly it failed. So after replacing the
solenoid the problem was fixed. You can also swap the solenoids to see
if the problem moves with the solenoid if not then you have to look at
the vvt and chain.
Peter
Pathfinder wrote:
“I would check the solenoid condition, remove it and clean
it and connect 12v to the connections and see if you hear any clicking“
Oh yes. Not only I checked which they are functioning; but I replaced them all on passenger side (magnets, sensors and even wiring harness).
you have to connect a scanner to check both intake cams
operations”
And yes, I’ve done that too. And that’s how I know under high load, the intake cams on both side actuated well to provide more torque. Only when it returned to low load then somehow the intake on passenger got stuck at 36 degree. Variable valve timing became fixed valve timing. Low speed torque lost considerably.
I believe the camshaft valve and/or dowel pin failed to lock/unlock (until the engine stopped and started again) is the cause. I can only know whether it’s true until I open the front cam cover and check it at 40 degree ADTC. Do you have any other thought, recommendations?
PS. Oh in order to do waveforms with Pico scope, did you have to connect to the crankshaft sensor in the back—or you simply intercepted the wire from SAM boxes?
Hi
Yes I think also check the vvt, yes you dont have to do the crank sensor, I have only 2 channel pico that is why I have used Handtek 1008c with the
8Channel, bit difficult with the handtek. I have back probe crank sensor at the PCM. You can just back probe the 4 x cam sensors – you might be interested
in this post https://mbworld.org/forums/s-class-w221/736464-chain-balance-shaft-gear-again-2.html. If you have pico scope you can go to the library and see if
someone has upload a good waveform for your car. But it looks like you need to check the vvt in any case, you have determine there is a problem
Peter
Thank you so much, Peter. Will get back to you once I make more determination and arriving at solution
Hello Peter,
I only have small fraction of your problems (code 1208). I understood that you use 4-channel scope to confirm. But didn’t see what exactly did you do to make the code 1208 to go away?
Appreciate your thought/comment.
Hi sorry for the late answer I have replaced the timing chain the balance shaft and all the guides and tensioner, with the 4x cam vvt solenoids. If you buy from the agents they normally sell a repair kit with all those parts in. Hope this will help. It looks like your problem is just starting and it might gradually give more faults later.