This topic is for a EXV2 model built in 2013.

I have a 2013 that I purchased in non-working condition (Li pack was at 0VDC). I've replaced the battery and resolved all BMS errors, but it will only drive at 5mph. The Curtis AC motor controller shows error code 51 and at one point showed 59. Curtis and E-ride documentation lists this as an OEM defined fault and I'm hoping you have insight to what that code actually means and how to resolve it. I've worked through the wire check guides and troubleshooting flow charts and I can say the inputs to the controller plug are working as expected (FWD/REV/Accelerator/Pedal switch/High voltage in/Low voltage out etc). The only hang up I've had is a failure to connect to the Motor controller over the OBD2 CANBUS - The High and Low from the controller are both near 0VDC and I've tested continuity from the pin side of the plug up to the wire where I'm testing voltage. Does the motor controller need to have communication with the BCM to function properly? Again, any help is greatly appreciated. Thank you. Matt

 

 

Controller error code 51 and the top speed of 5 MPH is a CANBUS communication issue between the battery management system under the driver's seat and the Curtis speed controller mounted in the passenger's side rear.

From models 2013 through most of 2014 there is a CANBUS isolator mounted in the battery tunnel just in front of the parking brake lever. It is a blue box. At the end of this box are LED lights. When all is working correctly these lights will be flickering very fast. Almost look dim. If these are not on or on solid there is a connection issue or this blue box (part# U5638A-N) is bad. Typically, it is a connection issue right at the box. Each of the black connectors going to the box unplug. These black connectors have screws to tighten each of the wires. Make sure they are tight and seated in correctly. Also, you can make sure the 2-pin connector has 12V. Markings may be on the bottom of box but each of the inputs are marked. GND and 10-30VDC is the input power which should measure 12-13.5VDC. The 3-pin CANBUS plugged into the same side as the 2-pin connector is for the low voltage side which wires run to the battery management system and programming port. The 3-pin CANBUS connector on the opposite side is the high side running to the battery charger, speed controller & dash display. This connector also requires a 120-ohm resistor part# U5685A-N.    

The 72V pack voltage and 12V accessory power is isolated from each other so this CANBUS isolator allows the low voltage and high voltage components to talk to each other while still keeping them separated electrically.

 

 

Thank you for your response. The B&B CANBUS isolator was the source of the P0A01 high voltage isolation error present in the BMS so I need to replace it. It does show traffic on the lights like I would expect but while it's plugged in I get a shortest wave value close to 1.3. I'll get that replaced but I'm concerned that the motor controller CANBUS voltages aren't between 2 - 4 Volts. Thank you for the quick response

 

 

Please note on the P0A01 that is pack voltage sensor fault. The BMS has a smaller connector on the upper left. This needs to read pack voltage (80VDC) between the two wires in this connector. Also check that it is plugged in. This is just a reference voltage and is not important. BMS uses all the sum of all the individual cell voltages to know the pack voltage.

High voltage isolation fault is P0AA6. This could be an issue, but this has not always been as accurate as it was thought it would be. We have since stopped using it. It can be turned off under battery profile tab/ fault settings tab/ and select dropdown of isolation fault detection circuit. Can be changed to low sensitivity or even ignore circuit. Note profile must be loaded from BMS then change setting and send profile changes to BMS. If password is needed it is 9139   

 

 

My mistake I copied the wrong fault code. I meant to talk about P0AA6. Thank you for the info on that, I had debated disabling it. I went back to the truck and disabled the isolation check then put the CANBUS isolator back in service and I have full speed now. Thank you so much for the help. What a great company to work with.