W212 E350 CDI Idling High

Aston Dabb

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Hello all,

Got an E350 CDI that seems to be idling at 800rpm instead of 600rpm ONLY WHEN CLIMATE CONTROL IS ON! When I plugged it into the Xentry I got Component ‘B37’ (Accelerator Pedal Sensor) is defective. At the time, the EML & ESP warning lights had just come up. Both with faults relating to this Component B37 Pedal Sensor. But I do not know why this would make it idle higher than it should do. I’m aware that this is common on the E350’s. The vehicle doesn’t get used very often at all if helps. It also has a jerk/flutter/misfire when driving and at approx 1500rpm but I think that is the fault with the defective accelerator. Any help appreciated thanks!
 

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Hello and welcome

They can idle higher with more electrical load. Having the climate on, increases the electrical demand.
 
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Aston Dabb

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@Blobcat, is there anything to prevent the increased idle happening; obviously there’s the option of no heater but not ideal this time of year haha!
 

mersum1es

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Idle, As above.

Fault code, how many times pedal fault was triggered? If very often, repair pedal first (check no corrosion in connector), then if problem are still there, run some test by xentry. EGR is opening/closing around that RPM, if speed is around 60km/h it could be torque converter problem too. Do a fuel pump/pressure tests.
 

malcolm E53 AMG

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How old is the battery climate control puts a heavy load on the electrical system and the alternator may be adjusting to this especially as the car is little used. I would check the battery out it should register 12.6V if fully charged engine off and I’d certainly change the battery straight away if it’s the original
 

Blobcat

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@Blobcat, is there anything to prevent the increased idle happening; obviously there’s the option of no heater but not ideal this time of year haha!
What condition is the battery in? Should sit at ~12.6v with the engine off.

I had a battery warning this week as I had both heated seats, air scarf, roof opening, lights and heater on.

Switched them off and alternator caught up - my battery is 18 months old.
 
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Aston Dabb

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@Blobcat @malcolm210 ; Battery hasn’t ever been changed. Vehicle is 2010. But the vehicle has been left for 5-6 weeks and it’ll still strike up and no low voltage faults so could the battery still be bad? Think last time we turned the engine off while connected to the star it read about 11.8v engine off and 13.8v going to the control units while running so a bit low I must admit
 
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Aston Dabb

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Idle, As above.

Fault code, how many times pedal fault was triggered? If very often, repair pedal first (check no corrosion in connector), then if problem are still there, run some test by xentry. EGR is opening/closing around that RPM, if speed is around 60km/h it could be torque converter problem too. Do a fuel pump/pressure tests.

Fault has been triggered once before being triggered again this time.. both of which it had been sat for a while before. In the CDI control unit, I got 101B00 fault; the signal of sensor 1 of component ‘B37 (Accelerator pedal sensor)’ is too high on the Xentry. And in the ESP control unit, I got Component ‘B37 (Accelerator Pedal Sensor)’ is defective.
 

Blobcat

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Should be >14 when charging, worth checking the date in the battery but it’s looking like it could do with charging / replacing.

If you can get a battery conditioner on it (CTEK or Optimate) then that would be a good start.
 
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Aston Dabb

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Should be >14 when charging, worth checking the date in the battery but it’s looking like it could do with charging / replacing.

If you can get a battery conditioner on it (CTEK or Optimate) then that would be a good start.
I will try to re-charge & condition the battery. Do the W212’s have an auxiliary battery also? If so, should I charge it? Will keep you up to date with it to see if idle comes back down after charging
 
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Aston Dabb

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@Blobcat , you can see when you go to rev the engine as soon as you touch the throttle to rev it; the LCD on the cluster dims
 

malcolm E53 AMG

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With a battery that age changing it is a good place to start and as above using a trickle charger while the car is stood for extended periods is a must really, modern car electronics don’t like under-voltage issues
 

V6Matty

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I’m starting to get similar issues with my 2011 212, I use it little these days after changing jobs and work from home, just like you I get a higher idle and the same dimming sensation as you in the cluster at times, my battery is also the original but after I’ve given her a decent drive it’s happy at 12.5 for days/week, much longer than that and it does start to drop off slowly. I’m just monitoring it and if it’s dropping after day 2-3 days I’ll be biting the bullet and getting a new battery
 
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Aston Dabb

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Should I hook a pulse repair up to the battery now now that this has happened then?
 
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Aston Dabb

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I’m starting to get similar issues with my 2011 212, I use it little these days after changing jobs and work from home, just like you I get a higher idle and the same dimming sensation as you in the cluster at times, my battery is also the original but after I’ve given her a decent drive it’s happy at 12.5 for days/week, much longer than that and it does start to drop off slowly. I’m just monitoring it and if it’s dropping after day 2-3 days I’ll be biting the bullet and getting a new battery
@V6Matty The same fault happened last year in the cold (I assume due to more consumables), and the car idling at 800 instead of 600. I think I will try to pulse repair the battery and trickle it; and see if that helps. If not buy a new battery
 

malcolm E53 AMG

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@V6Matty The same fault happened last year in the cold (I assume due to more consumables), and the car idling at 800 instead of 600. I think I will try to pulse repair the battery and trickle it; and see if that helps. If not buy a new battery

My 212 battery lasted 7 years so you have done well
 
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Aston Dabb

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The wife’s 169 battery is currently 14 years old and still going strong (when not under water that is)
I’m going to try conditioning the battery and if no success will replace it
 

aldsan

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Hello Everyone , i have MB E 350 CDI 2009 , with 240K. I have 2 mounths with problem of idling high
I start the car whenever in morning or at night is ok 600 rpm
when i start driving and stop 800 rpm . or some times is 600 rpm and when i start up the AC goes at 800 rpm
I changet the contron unit module of engine , again this problem
i changet 4 sensors , in footwell , in mirrorr , outside sensor again this problem , i change the ac climate control again this problem
i change the altenator again this problem
in the XENTRY is no errorr , one time show that power supply and now no errorr show
The battery level is 12.6 V engine off
and when i star driving some times stays 12.6 and some times 14.5 V but seem to be ok becouse if the altenator was fail the engine cant start up

Any Idea ??
i Have 2 mounths for this problem and no clue can be solved please Help
 
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Aston Dabb

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Hi everyone,

I know it’s been over a year; and I finally changed both the main battery and auxiliary battery on my W212 E350 a few weeks ago! This has cured the high idle for climate control, however now I have a separate issue. Now I’ve noticed every 1-2 days, the idle will go up and stay at 800rpm for a long period of time when driving, with different engine note and longer gear changes. Is this a DPF regen and should it be doing it this frequent? Is it worth plugging the Xentry in to see the Soot Content?
 


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