Crown RR 3020-45:
Fault code o7

Can any one help me machine hydraulics cut out, hyd pump is still running but lights on the top and lower dash that light up to tell you hyd function is activated have gone out, it flashes fault code 07 up for a sec then fault code goes out.
  • Posted 22 Jun 2012 07:18
  • Discussion started by brad_s
  • Southland, New Zealand
Showing items 1 - 2 of 2 results.
Hi thanks for help I will print this out and head back to the machince.
  • Posted 25 Jun 2012 09:54
  • Reply by brad_s
  • Southland, New Zealand
Code 07 has something to do with the accelerator pot being out of range. I have seen this come up continuously and the truck runs fine. A pot replacement and correct adjustment of the switches (fwd/rev) usually fixes this. The code 7 has nothing to do with the hydraulics. All the code are for travel. The hydraulics have no diagnostics that show up on the display, other than the battery meter. The traction card will cut out the hydraulics when the battery is discharged, but that is it. For the display, I would look at all the wiring and plugs to the distribution panel and the circuit selector box. Also look to make sure all the fuses are tight on the distribution panel The circuit selector box is at the top of the contactor panel. I think there are 2 or 4 screws on a cover. There is a circuit board inside the box. A common problem for the hydraulics cutting out is the K1 or K2 relay on the distribution panel. People call these "ice cube" relays because they are clear. Put a new K1 in. You can't go wrong on that. The k2 just supplies power to headlights or flashing lights. Seems like when I swap these relays, I find they are both bad, so I go with new.


What is your battery voltage when the hydraulics are activated? You may have a battery problem. The lowest you ever want to see with the lift motor running, assuming this is a 36 volt truck, is 28 or 29 volts. This would be with a battery that is almost completely discharged. You are going to see more like 33 or 34 volts with the pump running on a charged battery. Battery voltage going down to around less than 75% of rated voltage indicates a battery problem. I've been paid a lot of times to put water in batteries.
  • Posted 22 Jun 2012 12:44
  • Reply by Liftdoctor
  • Indiana, United States

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