Hi Mark,
Assuming these are the same as the OM XOP trucks (man up order picker). Can't tell you anything else as never worked on one....
FE32 "Height error"
Description - Monitoring of height measurement system.
Reaction: Reduced travel and lifting speed.
Cause: - Digital height is outside themonitoring window (±0.5V) for the analogue value.
- Lifting/loweringmovement without activated movement.
Lifting/lowering movement too fast.
- No pulses although movement activated.
Rectification: - Reset by turning the truck off and then on again.
- Check height measuring system, wiring.
- Teach in height measuring system.

Good luck.