I want to report my experiences resolving the dreaded “Check EV System” problem. In the end, the resolution of my particular problem was fairly straightforward but my path to getting to that resolution was anything but a straight line. Also, that warning can come from a lot of different causes. But for me, here’s what happened and what actually solved each issue.
I was charging my car at work when it stopped mid charge. I opened the driver’s side door and the warning “Charging Stopped by System Failure” was on the screen. I didn’t know if the issue was with the car or the charger so I reset the breaker and plugged and unplugged the charger a few times from the wall and from the car. Nothing helped. The car would charge for a few seconds or a minute but then stop. I turned on the car and the dreaded “Check EV System” was on the dashboard. I tried driving the car and found its performance to be very sluggish. Still, I had enough energy to drive home so I decided to try. Bad idea. About a mile away and I was in turtle mode with a warning that it was overheating. I thought that it was the battery overheating but I now think that this was wrong. Either way, I was disabled so I got the car towed home.
I found four useful sources of information. First, there’s this forum. It’s a forum so not organized but a lot of the information that I needed was here. Second, I subscribed to AllDataDIY for my model year of Rav4 EV (2013) and it was surprisingly complete. The problem is that the diagrams are line drawings without scale so it’s hard to know what part of the car the diagram applies to unless you’re already somewhat familiar with the car. Third, the most complete diagnostic and repair information that I found outside of those two sources was from Vladimir Leschenko’s different social media accounts. He has a YouTube channel and is active on his webpage http://alflash.com.ua
. It’s in Russian but the translations were understandable. Finally, I read about Tesla S powertrains from the 2012 to 2015 model years. That was my source of parts.
The car was still maneuverable so I bought two plastic drive-up ramps from Harbor Freight (P/N 69356, $45 or so) and used them to get clearance under the car. I needed to access the undercarriage of the car which was covered by two cowlings. I couldn’t get the clips loose so I just screwed screws into them and pulled them out. Later on, to reattach the cowlings, I tapped the receiver holes to thread them and screwed hex driven round headed screws in with washers and lock washers. I can’t remember if I used a 5/16”-18 or 1/4”-20 tap but I didn’t need to drill the holes out at all; the tap fit perfectly.
The traction motor battery is cooled by two pumps that circulate blue G48 coolant from the left side (from the driver’s perspective) coolant reservoir. The drive unit is cooled by a third pump recirculating blue G48 coolant from the right side reservoir. Without vehicle diagnostics, I didn’t know if the problem was with the battery pumps or the drive unit pump. Toyota calls the three pumps by three different part numbers (G9020F, G9020G and G9020H). I think that they are actually all the same part because they cost the same to the penny (>$500), look the same, have the same pin assignments and fittings… Also, this pump seems to be pretty common across many different models of cars. Lingenfelter offers a high performance Varimax Intercooler Pump with the pin assignments and part performance documented that seems to be the same. Bosch makes the pump itself and other manufacturers add the electrical interface. Toyota service says that they can only go by what they say in the their computer but I knew for a fact that the battery coolant pumps were identical to one another so I suspected that all the pumps were actually the same. Because of the error message that I had seen, I ordered two used Tesla S battery pumps from two different used parts suppliers on eBay, ev_rides and riceandbeansusedparts. Each was less than $100. The Tesla part number was 6007376-00-E. I think that the -00-E are just series numbers for drop-in replacements but I’m not sure. Also, I ran into some other Tesla pumps with different part numbers (6008047 and 1057257) and I’m not sure but I suspect that those are really the same part.
Disconnecting the 12V battery was easy enough. After that, I used the dismantler’s guide for the Toyota Rav4 EV to learn how to disconnect the traction battery by pulling out the fuse module under the passenger seat. It’s not hard but there are a couple of tricks. First, when you want to remove it, you have to pull harder on the handle than you’d expect until it clears the latch and then you can pull it straight up. Then, when you want to reinstall it, you need to pull the handle back while pushing down on the fuse module until you feel it engage. Only then do you push the handle down.
I bought three jugs of G48 coolant from the local O’Reilly auto parts store. They were about $20 each. I drained the coolant from the battery by freeing the hoses that were connected to the battery and, draining as much coolant as I could using gravity and then using an air gun with the pressure regulated down to push the rest out. It’s a messy operation and it takes patience. I removed and replaced both of the battery coolant pumps. It’s difficult to do this if you don’t know how the Sumitomo automotive connectors work. You have to push pretty hard on the lock-lever button on the connector and then, when you’ve raised the latch over the tab, you can withdraw the electrical connector. Also, don’t replace the spring hose clamps with worm drive hose clamps as the spring drives are less sensitive to temperature changes.
I tested the pumps that I removed using some test equipment from my lab. It’s not simple to do this, unfortunately. The Lingenfelter VariMax pump manual provides a guide. I connected the battery up to pins 1 (+) and 2 (Gnd) using alligator clips with insulative sleeves and I connected pins 3 and 4 up to a TTL output from a function generator operating at 2 Hz with a 50% duty cycle. I could hear the pumps start up after a few seconds and spin fairly vigorously so I considered that they tested good. But I had the new ones so I changed them out anyway. This didn’t solve the problem.
Next, I removed the drive unit coolant pump. This was much easier to do. You can get to it from under the hood. It’s easier if you use the second hood prop hook hole to keep the hood open wider. I drained and replaced the coolant on the drive unit. I replaced the drive unit coolant pump with one of the good battery coolant pumps. When I tested the drive unit coolant pump, it started and stopped over and over again and never got to the same speed as the other pumps. I don’t know for a fact that this is abnormal behavior but I suspect that it indicates a failing pump.
I asked around and one of the parts suppliers said that if a battery pump looked the same, had the same electrical characteristics and pumped in the same direction, I should be able to safely replace the drive unit pump with it. Writing this last sentence, it seems like a no brainer. After I installed it, I tried test driving the car and it turtled after about a mile. I opened the hood and the coolant had fallen in the drive unit reservoir. I suspect that there were air bubbles in the lines. I added more coolant and ran the car so it would be absorbed. Since then, the car has been running.
There was still the matter of the Check EV System message. It’s a bit of a nuisance because the car won’t go into Sport Mode when that message shows. But also if anything else were to go wrong I wouldn’t know about it. My normal code reader didn’t work. I read in this forum that you could clear codes by disconnecting and reconnecting the 12V battery five times but this didn’t work. I purchased an OBD to USB cable (item SV46-D1 from OBD2Eshop.com, about $15) and it came with Toyota TechStream software. IMPORTANT: This and similar items only seem to run on 32-Bit windows. I’m running on a dedicated laptop with Windows 10 32 Bit installed on it. I read the code from the EV system and found that it was just a generic warning to check the Tesla system for more details. I cleared the code and it did not recur.
My next step will be to gain access to the Tesla system itself to deal with similar issues in the future. Vladimir Leschenko has done this and someone posted an installer for the Tesla Powertrain Diagnostics extension to TechStream here: https://mhhauto.com/Thread-Toyota-RAV4- ... pid1777604
I hope that this helps someone.
Best of luck.