[fabbrisd1]

Please understand we are talking about the Bosch brand CPS sensor (from a reputable internet source like autohausaz.com) if you buy that part at a local retail auto parts store (or eBay) non-Bosch sensors are China made and really a sh*t part.

On your CEL light (not related to CPS since CPS sensor failure most cases does not setoff a CEL light) - you need the "codes" read (non-Mercedes read can do for a start) and by posting that code(s) we can give better advance that issue.

Keep the faith !

 

[fabbrisd1]

CPS and tool

At the top of this forum are the "stickies" (worthwhile documented DIY instructions that "stick" around).

There will be a DIY for the CPS - get the Bosch part on order, get it in, then collect the right bit/extensions to do this job - requires patience and small hands.

On the diagnostic scanner - check your local retail auto parts stores, who often will either "scan" codes for free (have paper and pen to write them down) or "rent" you a scanner for a fully refundable rental fee so you can scan in their parking lot.

A basic code reader is like $22 from on-line sources - and small enough to fit in the glove compartment:

U380 OBDII OBD2 EOBD Engine Scanner Trouble Code Reader | eBay

 

[fabbrisd1]

Please return the unused Autozone part if you can - that is a China made part known not to be reliable.

Genuine/correct Bosch only - or you will have the problem again - quite soon.

A part warranty doesn't help when it happens agaon on the road..

 

[fabbrisd1]

Pickles is correct - MAF cleaner is a non-ammonia and non-residue cleaner. Some "electronics parts" cleaners are - some are not - better to spend the $9 for a can labeled MAF cleaner and be crertain... lot's of other uses for MAF cleaner for other stuff....

 

[fabbrisd1]

Cass... trying to follow the history....

1) you hav had CPS replaced - and that cured "engine-warm-dies-doesn't-start" - so you're not going "dead" out and about driving - right ?

2) Now - you're saying you notice "sometimes" the starter has to crank a bit before engine starts - and sometimes the engine starts up right away - right ?

On #2 - normally is not a electrical thing - can be overall with age/mileage - for improvement you might consider addressing fuel + air maintenance stuff - like fresh-fuel-filter-Bosch/Mann - 1/2 bottle Stabil in the tank - fresh-air-filter-Mann/Hengst - pull and check spark plug - stuff like that..

 

[fabbrisd1]

One "suspect" may or not be the DuraLast CPS - which unfortunately is a China made knockoff part (no - it is not made by Bosch) and the shame of it all is autoparts stores charge as much for it as buying the correct Bosch-brand part.

I am not saying that is the problem - I am saying it "could" be part/all the problem.. unfortunately most parts stores won't accept it back for credit as it is a "electrical" part.

If you have the "old" CPS - or you personally installed the DuroLast part - then you will know which type (one-prong, two-prong) CPS type it is - if you want to move to correct Bosch-brand part.

When forum recommends particular brand part - it is from experience for that part.

Good luck - you are pointed in the right direction with your intent to take good care of your W210..