Ryobi RY48ZTR75 User manual

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SERVICE CENTER ELECTRICAL SYSTEM TROUBLESHOOTING AND TESTING GUIDE
RYOBI RY48ZTR75/100 AND RY48140 RIDING MOWER

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TABLE OF CONTENTS
•WARNING
•ZTR Mower Overview
•Brushless Motors
•Using this Manual
•ZTR Block Diagram and Control Flow
•Troubleshooting: General
•Troubleshooting: Detailed
•DMM and Other Tools
•Component Locations
•Controller and Label Locations
•Main Battery Connection
•Testing Main Fuse
•Testing Battery Voltage
•Control Panel
•Testing PTO Switch
•Testing Headlight Switch
•Testing the Drive Speed Switch
•Testing Blade Cutting Speed Switch
•Testing Fuel Gauge / Hour Meter
•Testing Key Switch
•Testing USB Port
•Testing the Neutral “Zero” Switches
•Testing Headlight Assembly
•Testing Accelerator (angular transducers)
•Testing Brake Switch
•Testing Beeper
•Testing Seat Switch
•Testing Primary Blade Motor Controller
•Testing Secondary Blade Motor Controller
•Testing Drive Motor Controllers
•Testing Blade Motors
•Testing Drive Motors
•Testing Drive Motor Hall Sensors
•Testing 48V-12V Converter and fuse
•Testing Relay
•Testing Relay Diode
•Testing Charge port and interlock
•Testing the Battery Charger
•Battery Charger Error Codes
•ZTR Beep Codes
•Testing the Temperature Sensor
•Wire Harness
•Pre and Post-Repair Checklist
•Electronic Tips for the Mechanical Small Engine Tech
•Electronics Terms, Symbols and Tools
•Using the Digital Multi-Meter (DMM)

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WARNING
THIS MATERIAL INTENDED ONLY FOR TECHNICIANS TRAINED IN ELECTRICAL REPAIR.
Technicians should wear personal protective equipment, such as rubber
gloves and safety glasses.
Dangerous voltages /currents are present. Exercise caution at all times.
This manual assumes knowledge of basic electrical equipment such as DMM (Digital Multi Meter)
and clamping Amp Meter to measure voltage, current, resistance, continuity, and diodes.

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The RYOBI ZTR riding mower is completely electrical, consisting of 4brushless
motors and acontroller for each motor:
•Abrushless motor and controller for each of the 2blades
•Abrushless motor/controller to drive each rear wheel.These Drive Motor Controllers
also contains the “brains” that responds to various inputs such as the accelerators,
seat switch,etc.
OVERVIEW

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Brushless motors operate quite differently than brushed motors, which you may be
used to (i.e. a starter motor).
Abrushed motor can be quickly tested by applying voltage to the two terminals.
Brushless motors can be recognized by 3wires. These 3wires require a controller to
operate them and to turn on these 3 phases in a precise fashion similar to spark plugs
firing a 3-cylinder gas motor.
Applying avoltage directly to these phases will cause damage.
BRUSHLESS MOTORS

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Any blue text can be clicked on to jump directly to the page of that topic. (This document
is also printer-friendly, so you can have it in front of you while servicing the mower.) If
you print this document, we recommend printing it in landscape mode and in color
ABlock Diagram shows the general flow to visualize how the mower is connected and
achart shows general symptoms/solutions for repairs.
Electronics tips ,Terminology and Using a Digital Multi-Meter (DMM) are included for
the technician familiar only with gas machines.
USING THIS DOCUMENT

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TOOLS NEEDED
Torx
T27
T30
T40
Screwdrivers
Cross tip
Flat blade
Sockets and
Wrenches
8 mm
10 mm
13 mm
14 mm
15 mm
17 mm
19 mm

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48V
Batteries
Main Fuse
Charge
Port/lockout/
battery temp
48V to 12V
(DC to DC)
converter
Relay
Fuel
Gauge
Brake
Switch
Beeper
Seat
switch
Fuse
Primary
Blade
Control
Secondary
Blade
Control
Motor Motor
Head
Lights
Accelerator
Note: A detailed wire harness diagram is
located later in this document
USB
Important:Primary and secondary
have a communication link. If one
blade motor or controller fails,
BOTH will shut down.
48V
Secondary
Drive
Controller
Accelerator
PTO
Drive Speed
Switch
Blade
Speed
Key
Switch
12V
Left
Neutral
switch
5V out
Motor
Hall Sensors
Primary
Drive
Controller
Motor
Hall Sensors
RIGHT
Neutral
switch
Enables
BLOCK DIAGRAM AND CONTROL FLOW

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•Follow the Block Diagram on the previous page.
•Check for loose/bad connections.
•Test the easiest components first. (power, key switch, DC-DC converter)
•Mower should be fully charged (if possible)
•Before disassembly:
–Attempt to charge mower (note any error LED indications)
–Check for voltage at charge port.
–Check USB Indicator and Headlights are functional (this tests the 48V-12V converter)
•Remove Instrument Panel cover
–Test Key Switch
–Check all other connections while panel is removed.
TROUBLESHOOTING: GENERAL

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Use the block diagram as aguide
Also refer to the beep diagnostic code chart
1. Verify the battery charger is functional by plugging it into the charge port on the back of the mower and let the mower fully
charge.
2. If necessary, further test the charger and charge port.Replace as needed.Charge port,Interlock, and temperature sensor
should be replaced together.
3. Test the key switch by operating it, making sure it has atactile “click” when turned on or off. Replace if necessary
4. Test and replace main relay and diode as necessary. (Note: when you turn the mower on, you should hear the relay click)
5. Check the main fuse.If it is blown, check the system for signs of ashort circuit before replacing the main fuse
6. If the fuel gauge has power, but no display or malfunctions, replace the fuel gauge
7. If ONLY the fuel gage works when the key is turned on, test/replace the 48-to-12V DC converter and 5A fuse as
necessary Note: this fuse is acommon part available at any automotive store
TROUBLESHOOTING: DETAILED