You are the technician. A customer dropped off a 2010–2019 E-Z-GO TXT 48V — the platform with the Curtis 1206HB-5201 controller (48V/250A, SepEx, 16-pin harness plug, OEM P/N 612632). Read the Work Order, find the failure, fix it, and return the cart.
• Battery pack: four 12V deep-cycle batteries in series. Fully charged and rested: ~12.6–12.7V each, ~50.4–50.8V pack. A battery with a failed cell reads ~10.5V rested and collapses under load. (Many fleets convert to 6×8V — this cart is the factory 4×12V setup.)
• Throttle: the E-Z-GO Inductive Throttle Sensor (ITS), P/N 25854-G01, in the pedal box — a two-wire inductive sensor plus a separate foot micro-switch. It is not an "MCOR" (that's Club Car).
• Solenoid: the controller (pin 12 of the 16-pin plug) drives the main solenoid coil.
• Precharge: with key on and solenoid open, the controller's B+ terminal must already sit within 4V of pack voltage through the precharge resistor. If contacts fail to close, B+ shows precharge voltage at rest but collapses the moment you press the pedal.
• Motor: separately-excited (SepEx) DC motor, four terminals. The armature circuit runs B+ → solenoid → A1 → armature → A2 → controller M stud; the controller completes the circuit to B− internally. The motor never connects directly to battery negative. F1/F2 run to the controller's field studs.
• Run/Tow switch (under seat): in TOW the controller, the electronic (regen) braking and the warning beeper are all dead. The #1 "dead cart" call is a cart left in TOW. Wired in series with the key switch.
• Charger interlock: a reed switch in the charger receptacle tells the controller a charger is plugged in and inhibits drive. The controller's interlock input should read pack voltage with the charger unplugged — 0V means a stuck/damaged reed switch (a common failure, per FSIP).
• Speed sensor: mounted on the motor. If it fails the controller flags SPEED SENSOR FAULT and drops into reduced-speed limp mode.
• 12V accessory circuit: the light kit, sound bar and LED whips do NOT run on 48V — a voltage reducer (48V→12V DC-DC converter, 30A) feeds them through a 15A accessory fuse, with a shared ground splice back to B−.
The TXT48/1206HB has no onboard blink codes — faults are read as text on the Curtis 1311 handheld programmer (diagnostic port + Molex-to-Tyco adaptor). Real fault names you'll see: THROTTLE FAULT, LOW BATTERY VOLTAGE, MOTOR STALL, SPEED SENSOR FAULT, HPD, MAIN WELDED, THERMAL CUTBACK, OVERVOLTAGE.
HPD (High Pedal Disable): if the key comes on while the pedal is pressed, the controller refuses to drive until the pedal is fully released — that's a safety feature, not a failure.
(Older 36V PDS carts with the Curtis 1206MX instead beep fault codes through the reverse buzzer — key OFF, Run/Tow to RUN, cycle F/R neutral→reverse 5×. Different platform, not modeled here.)
| Measurement | Good reading |
|---|---|
| Pack rested (key off) | 50.4 – 50.8 V |
| Each 12V battery rested | 12.6 – 12.7 V |
| Pack under full-throttle load | ≥ 48 V (healthy pack) |
| Controller B+ (key on, not moving) | within 4V of pack (precharge) |
| Voltage drop across solenoid studs (driving) | ≈ 0 V |
| Voltage drop across each battery interconnect (driving) | ≈ 0 V |
| ITS signal — solenoid click point | 1.0 ± 0.3 V |
| ITS signal — full pedal | 2.7 ± 0.5 V |
| Voltage reducer output (key on or off) | 12.8 – 13.4 V |
| Voltage on accessory ground (loads on) | ≈ 0 V |
| Solenoid coil | ≥ 100 Ω |
| Armature A1–A2 / Field F1–F2 | 0.3–1 Ω / 1–2 Ω |
You only score if the failure is actually fixed. Half is efficiency — every unnecessary part replacement costs points (bench-test before you condemn!). Half is tidy work: reconnect everything, clear fault codes, close your tool windows, write the diagnosis, complete the checklist.