Mercedes Repair Questions? Ask a Mechanic for Answers ASAP
Hi, when you say it starts intermittently does the starter crank the motor but it won't start?
Nothing happens with repect to the cranking. When it decides to crank it will start.
Ok, this sounds like a typical failure of the K40 relay module. The module is located under the hood at the right rear in the module box.
Wouldn't this give me a relevant fault code?
Sometimes you can take the module out of it's bracket and tap on it and get the car to start. The fans running is also a symptom of the bad module. You won't get fault codes for the module.
Is this a repairable item? How much should a new one cost?
The part # XXXXX XXXXX 540 00 72 msrp is $152.00.
Doesn't the K40 contain a number of relays. Which one would be associated with the start problem?
Yes it contains your starter relay among others. I doubt that you can repair it. You can find them online for a little less.
Thanks for your help I'll try the disconnect and tap it method first.
It should be in the box near the battery. I've attached a picture below.