Hello,
I recently purchased a 2002 Gem E4 that was not functioning at all. I replaced all six of the batteries, replaced the charger(ride 4 fun) and replaced the T1 controller with a rebuilt T2 controller. When driving the Gem car it will immediately go into Turtle mode and flash code -90. Code -90 indicates that terminal 1 is shorted to ground, input sensor error and to check the motor controller. The rebuilt T2 controller has the jumper wire installed and I have tried on terminal 23 to terminal 1, Terminal 21 to terminal 1, terminal 2 to terminal 23 and terminal 2 to terminal 21 as there were multiple professionals who said to hook up the jumper wire up those different ways. None of these connections solved the turtle mode/code -90 issue. The electric motor seems to be working fine but I am wondering if it is causing the problem. The exterior casing is pretty rusted. I Used an ohm meter and there does not appear a short but two of the ohm readings are fairly different from one another. I drove the cart in turtle mode for 2 miles and the motor felt pretty warm but not scalding hot. Any recommendations or advice would be greatly appreciated. Thank you