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Curtis Code 93
Encoder LOS (Limited — controllers 1234 / 1236 / 1238

Possible causes (from the Curtis manual)

1. Limited Operating Strategy (LOS) control mode has been activated, as a result of either an Encoder Fault (Code 36) or a Stall Detect Fault (Code 73). 2. Motor encoder failure. 3. Bad crimps or faulty wiring. 4. Vehicle is stalled.

When it sets / how it clears

Set: Encoder Fault (Code 36) or Stall Detect Fault (Code 73) was activated, and Brake or Interlock has been applied to activate LOS control mode, allowing limited motor control. Clear: Cycle KSI or, if LOS mode was acti- vated by the Stall Fault, clear by ensuring encoder senses proper operation, Motor RPM = 0, and Throttle Command = 0. Curtis 1234/36/38 Manual, OS11

Effect of the fault

Operating Strategy) Enter LOS control mode.

Curtis 1234/1236/1238 controllers are fitted to many electric forklifts and industrial trucks (including models from Chinese brands that use Curtis control). If your display shows code 93 with a Curtis controller, this entry applies; the vehicle maker’s manual may add model-specific notes.

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For controller, contactor, sensor or throttle parts, send us the code (Curtis 93), controller model and vehicle model on WhatsApp — we quote genuine and OEM parts for export.

Source: Curtis 1234/36/38 Controller Manual, OS 11, Section 8 Diagnostics & Troubleshooting, Table 5. Compiled 2026-10-29. No affiliation with Curtis Instruments.