I started getting the following error message: Coolant System error Service required ID: 1425 Data:0x02000000 I took my car in and they told me that I needed to have the ESS coolant pump replaced. In the more detailed logs in debug mode, it says something to the effect that the coolant pump isn't drawing enough current. This either indicates that the pump has worn out or possibly that the coolant is just low. I ok'ed the pump replacement and waited and twiddled my thumbs for them to order the pump, receive the pump and schedule me for service. Since that path was taking forever, I decided to just change it myself. A Tesla technician told me it was trivial to replace the pump. With some help of some forum members, I got the Bosch part number (Tesla told me they couldn't give me the part number). The coolant pump is a common Bosch supercharger intercooler pump used on cars like the Mustang GT500 and supercharged Range Rover. The Bosch part number is 0 392 022 002; Tesla refers to it as PUMP-ESS COOLANT PCA12 (2004503). Tesla charges about $400 with tax for the pump and $280 to install. I bought the pump for about $100 (it's widely available on the internet) and my brother works for free. Here is the pump that came out of the car. From the sticker, it was manufactured of January of 2009 so it was the original pump for the car. Here is the new pump that I bought. I appears to be identical in every way the original one. Disclaimer: You will certainly die, destroy you car and burn your house down if you follow my directions; don't blame me when that happens. The pump is located on the front side of the rear passenger wheel well. Here's what we did to replace it: 1. Disable the APS so that the ESS isn't pumping coolant 2. Jack up car and put a catch pan under the car 3. Remove rear passenger wheel 4. Remove panel on front of wheel well. There were 5 or 6 hex head screws holding it on 5. Disconnect the 12V connector. It has a neat little sliding lock. 6. The pump access isn't great, but it isn't terrible. Surprisingly, the pump is just resting on some styrofoam and more or less held in place by the fairly rigid coolant hoses. The hoses on both sides are pretty short, so they would be difficult to clamp off. Because of that, we took some fairly large markers and put a cone of masking tape on the end of them for jamming in the hoses to stop the coolant loss; I think the hose is about 3/4". We checked our improvised tool with the new pump inlet/outlet to make sure they were reasonably sized. We disconnected the hoses and pushed our improvised stops in as quickly as possible (this is where having two people is good). We hardly lost any fluid (maybe an ounce). 7. Remove the stop from one hose and connect the new pump in the same fashion as the old pump. 8. Remove the stop from the other hose and connect the new pump to that hose. 9. Re-attach the 12V connector. 10. Pour some water where the coolant was lost to clean off the inside bottom pan of the car. 11. Put the wheel well panel back on. 12. Put the wheel back on. 13. Lower the car. 14. Re-enable the APS. 15. Make the pump run a bunch of times by opening and closing the charger port to get the air out of the system. Here's a picture of where the pump is located. I didn't get any good close-up pictures. I would say it took us about an hour to replace the pump.