I have an Error message 50 coming up when iturn on my eliptical

SOURCE: I get an error message on my Precor EFX5.17

Error 54 - Target Pulses Lost During Operation... Description... This error is associated with the 5.17 EFX. This error indicates that at some time after the initial start up sequence was successfully completed, the gear motor was instructed to move and no response was seen from the motors revolution sensor. Possible Causes (1.) The F2 fuse is blown.... (2.) Damaged or Intermittent gear motor wiring.... (3.) Bad gear motor.... (4.) Damaged gear motor target... (5.) Bad lower PCA.... Possible Remedies.... (1.) Remove power from the 5.17. Remove the F2 fuse from the lower PCA. Measure the fuse with an ohmmeter. The fuse should measure 1 ohm or less. If the reading is significantly high, replace the fuse. If the F2 fuse was blown there may have been a reason that will cause the fuse to blow again such as; damaged gear motor wiring or a bad gear motor..... (2.) Carefully inspect the gear motor wiring for intermittent or damaged wiring or connections. Replace or repair the wiring or connections as appropriate..... (3.) With power removed from the 5.17, remove both wires from the gear motor. Measure the gear motor resistance with an ohmmeter, it should read approximately 9 ohms. If the reading is significantly low or significantly high, replace the gear motor..... (4.) Visually inspect the gear motor target, if it is ripped, torn or badly scratched, replace the target..... (5.) Measure the voltage at the gear motor during the start up sequence, it should measure approximately 12 V.D.C. The voltage would only be present between the time the sequence was initiated and an error was displayed.. If the voltage is significantly low or absent and the F2 fuse is good (see step 1), replace the lower PCA......
Hope this has helped you.... Thanks...