92Service Manual – CS7010™ 22 - Steering System
Troubleshooting
Fault Codes
The steering controller has very robust fault code capabilities. Since most problems will result in setting a
fault code, whenever there is a problem with the steering system, the rst thing you should do is check for
fault codes.
All fault codes for all system modules are displayed by the Main Machine Controller. Because multiple
related fault codes may span different machine modules, all fault codes are presented in the Controller
chapter of this manual. The A5 Steering Controller fault codes are listed on page 57.
Symptom Troubleshooting
Very few steering system failure scenarios exist that won’t originate with an error code. Virtually all faults
between the steering controller and steering actuator are monitored by the controller, including signal loss,
miswiring, and short circuits. The TFD and steering limit switches are the primary components that can
have a failure mode that is not automatically detected. These failure modes are also partially interrelated, as
one failure may impact the other.
Loss of Steering Resistance
The primary cause would be a signal loss between the steering controller and the TFD. Troubleshoot for
broken or disconnected wires by checking voltage between them to be non-zero volts. Check the TFD coil for
resistance of around 5 ohms.
Excessive Steering Resistance and/or Drive Wheel Position Errors
The outward symptom would be excessive voltage at the TFD coil, however, this is most likely caused by the
steering controller detecting one or both steering limit switches being closed when they shouldn’t be.
• A short to ground on the J6-26 wire from the controller would cause the TFD coil to be at maximum
torque all the times. Aside from difculty turning the steering wheel, all other steering functions would
respond normally.
• If one or both of the limit switches have failed in the on (closed) condition, the steering controller will
show the following error codes: 4-227 Drive Enable Open, 5-110 Application Fault.
• If one sensor is closed, the steering wheel will not turn in that direction, but will turn in the opposite
direction. However, the drive wheel will only move slightly, and further steering commands are ignored.
• Similarly, if both sensors are closed, the steering wheel won’t turn in either direction and the wheel won’t
move.
• Also note that if a limit switch was tripped at an incorrect location (such as a stray piece of metal near
the sensor, or your own troubleshooting steps), but then later returned to normal operation, the steering
controller will remember this position as though it was a valid limit even though the sensor no longer
trips at that position. This would be a false limit position, and the controller needs to be reset (machine
power cycle) in order to ”forget” this false position.
Limit Switch Testing
Because the limit switches are mechanical switch contacts, they can be tested as a conventional switch using
an ohm meter. When a non-magnetic steel object is positioned near the face of the sensor, the reed switch
should close. However, note that using a magnetized object may result in unexpected results if the magnet
polarity opposes the North/South polarity of the switch’s internal magnet.
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