I have a 2005 XF NA Coupe with 77,000 miles, and auto trans. After driving yesterday, about 50 miles, at speeds in the 55 to 65 range, when arriving home I was hearing a ticking noise at low speeds. At about 10 to 20 MPH the noise sounded like someone driving a nail with a hammer. Could only hear this with the windows down. Windows up, it could not be heard. As the speed varied so did the ticking either slowed or increased with the speed. Coincidently, I had the "check engine" light on. It's been on for a few weeks. My code reader gave me the code P 0410, secondary air injection. Maybe the two are related, and maybe not.

In checking this site it seems that the code is because of a faulty relay in the RCM and it is not a problem to drive with it that way. One quote said the faulty relay is the fault 99% of the time.

As for the ticking noise, does anyone have any suggestions? It does not make the noise when cold or just starting out on a cruise. Could it possibly be the two piece driveshaft, bad U-joints, transmission, or rear end? Again, it only makes the noise after driving about an hour and only at low speed.

If anyone has any idea's or suggestions, I would like to hear them.

Thanks,

Jim

 

Hi Jim! There are a number of things it could be (without) spending a lot of money. Have you picked up the front end and checked the front tires for a rock or nail/screw in the tires? You can then check wheel bearings and other suspension parts as well (and afterwards, the rear picked up to check those bearings/suspension items)? Checking these as a minimum doesn't cost a penny. By your description it only happens when moving, so have you then eliminated the engine? If so, when you are checking the rear suspension/bearings, AND BOTH WHEELS are on 'jack stands', place the car in neutral and individually spin the tires (both of them) and see if you hear a 'tick'. If not (while on secure jack stands), CAREFULLY start the car with foot on brake and shift to 1st gear only! This simple test may give you an idea if it is in the transmission to rear wheels. DO NOT REV THE ENGINE, the drivetrain will spin freely by itself and not 'run away'. Keep notes, and maybe you can find it before someone charges you for something you can locate, (and) only then decide how to fix it if necessary. Keep us in the loop? Good luck!


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Ghost - Thank you for the response and the suggestion. I will try that and see if I can find anything. Since I have to drive it about 40 or 50 miles to get everything up to temp, I might try a friend who is in the repair business and see if he would be willing to put it on his lift to check it. He has a lift that lets the wheels hang like when you change a tire. Since I'm now 83 years, it would be easier on me. Maybe I shouldn't be playing with cars at 83 but I love driving the thing.

Jim

 

It's a Mercedes. Check you brake pads.

Also, be sure the lug nuts have not been over tightened as that will warp your rotors.
I believe the torque limit is 78 lbs.