CLS 55 not starting

[1my]

Hi guys, hope someone can help me with a problem i came across today.

Never had any start up issues before, took the car out today parked and returned to the car and it wouldn't start.

It had power and was cranking the engine but just wouldn't start. No warning messages on the dash.

After trying 4 times i decided to leave it for 20 minutes and try again, this time it started.

The engine managment light is now on and obd reader points to "crank position sensor A circuit"

Is this just a case of a faulty sensor that needs replaced or could it be something else?

Any help appreciated, thanks

Imy

 

[merc85]

Yep sounds like a crank sensor fault.

 

[whitenemesis]

If the engine was warm when you tried the start, yes, CPS needs replacing. Classic symptom is hot engine not starting, once cooled it's fine..

 

[kopkid]

Yes cps I did mine few months ago easy to replace sitting right behind the engine between gearbox took around 20 minutes

 

[Gbrowncls55]

Deffo crankshaft positioning sensor. I have had to replace it on all 4 Mercedes I have owned. Don't suppose it will be too !long before the cls55 needs one too. Non starting or random starting classic symptom. About £150 fitted as far as i remember.

 

[1my]

Sounds like an easy fix. Will get a new sensor ordered from dealer tomorrow and fit it myself

Thanks

 

[kopkid]

Just a 8mm bolt holds it down very easy change,, just fully open the bonnet

 

[Major774]

My CPS failed on the petrol forecourt after fueling up, so I know the pain lol.

 

[Lenny63]

Mine failed recently too - same car

Exact same symptoms

You might appreciate this little video of where it is located ....

https://youtu.be/H3z7jgUlYxs

You'll need a 1/4inch drive ratchet with a small 1/4 extension bar but you MUST buy an E8 torx bit for the CLS55 in 1/4 driver size - draper do one , is about £5

Here is what I used

 

[ChrisCLS55]

Crank sensor issue is common and failed on mine.

 

[1my]

Im glad its an easy fix. I ordered the sensor from Mercedes and it was i stock. Cost around £110.

Hopefully if i get time tomorrow it should get fitted.

 

[merc85]

I'm thinking about replacing mine as a precaution reading all these failures, 110k its got tobe nearing the end of its life.

 

[AMGeed]

I'm thinking about replacing mine as a precaution reading all these failures, 110k its got tobe nearing the end of its life.

Mine failed at 101k. No knowing how many times before that

 

[Lenny63]

Mine failed at 79k lol and the one that came out wasn't an OEM one it was the Bosch one

 

[merc85]

Mine failed at 79k lol and the one that came out wasn't an OEM one it was the Bosch one

How do you know Bosch don't make the Original bud?

 

[Adamccc]

Mine failed last month at 20k! Glad to see it's not just me

 

[Lenny63]

How do you know Bosch don't make the Original bud?

To be fair Gav they most likely do

I'm just highlighting the fact that even at 79k mine had already had a replacement
Seems to be a real common issue