Hi Guys

Im hoping someone here knows a trick to this, or else im afraid its going to be expensive!

To start, there are no error notifications on my 2006 CLS 500.

I washed the engine bay with a light spray of hose water. soaped it and rinsed in off. When i started the car, the notifications were: ABS, ESC, Tire pressures. Also the steering wheel had much more resistance (still driveable). The tranny would not let me shift from park until after a few tries.

Intermittently, other warnings popped up after i tried starting the car a few times: Brake service, and one other i cant remember.

I checked the OBD2 codes and this was there: P0600. A Google search says "PCM (Power Train Control Module) Serial Communication Link Malfunction"

So this PCM does appear to be related to those functions. Any ideas before i go and start buying new parts??

Oh and the battery did go flat a few months ago, but ive been charging it and it tested fine today.

Under the hood there are a number of Sams (fuse boxes). Open them all up and dry them out. Obviously water got into the boxes when you washed the engine and Sams do not like water. Hopefully no permanent damage has been done. Good luck.

Ok so i opened up the fuse box and looked at those sams. The few i pulled out were bone dry. Everything was super dry.

Unfortunately the issues are still there.

Does anyone know what i could do to figure out what part i need to replace?

Put it in your garage, fire up a heater and de-humidifier with the hood up, and let it sit for as long as two weeks to dry out the connections. You have moisture in the connectors.


Still much easier than an AH-64 Apache when the mechanics left the cockpit open on the flight line and a snow storm hit that night. *That* took a while to dry out....


FWIW, WD-40 is called that because it is "Water Displacement Formula 40". 40 refers to the number of attempts it took for the researcher to get it right. I used WD-40 multiple times on my old Ford pickup with the inline 6-cylinder. Distributor was in the front and, whenever I drove it in the rain, the ignition would short out, I would pull to the side of the road, raise and clamber under the hood, and spray WD-40 on anything and everything related to the ignition. It then started every time. Of course, I also had lots of dust sticking to the engine. But...my engine ran.