W202 CDI Starting Fault

[Gemini18]

First time this has happened. (2000 Reg C220 CDI Auto 155K)
Following a 3 hour Motorway trip after a stop of 30+ mins the Engine failed to turn over (Key operated starter)
Checked the normal points that inhibit starter motor ie .In Park - Battery - lose connections all seemed fine.
Called RAC (4 HOUR WAIT) left it around 30 mins, retried, then it started OK.
Not sure where to look ?could it be starter motor relay issue or will it need to a workshop for fault code reading.
Any advice/thoughts would be appreciated.

 

[DSM10000]

You said "Key operated starter"

So did it turn over at all but not start?

A failing Crankshaft position sensor commonly shows as a refusal to start when hot but will then start as it cools down.

 

[grober]

The later W202 models were early canbus IRRC so best diagnosed with star or equivalent- ONE POSSIBILITY is a faulty gear selector unit which may be telling the starter the car is in gear when its not? starter will only turn over with selector in park or neutral position.

Mercedes C-Class gear selector module fault

C-Class automatic gear selector module fault prevents gear selection in both directions our rebuild will resolve this problem

www.ecutesting.com

lot of repair videos on you tube on this for w203