68 - 1
Section F
9803/3280
Section F
68 - 1
Issue 1
Service Procedures
Powershift Gearbox - 6 Speed (ShiftMaster)
Electronic Control Unit
The PS766 6 speed gearbox is controlled by an Electronic
Control Unit (ShiftMaster ECU). The ECU is located behind
the front console as shown at
A
.
The ECU is housed in a rugged case protected from ingress
of dirt and moisture. Gearbox faults are more likely to be
caused by faulty or damaged wiring, electrical components
or hydraulic faults than by failure of the ShiftMaster ECU.
Fault Finding
When fault finding note the following:
Make sure you understand the normal operation
characteristics of the 6 speed gearbox. Some characteristics
may be interpreted as faults by some operators. See
Basic
Operation - ShiftMaster Operation Characteristics
.
The ShiftMaster ECU incorporates ‘Limp Modes’. These
modes can operate in response to other gearbox faults.
Make sure you understand the characteristics of the ‘Limp
Modes’, see
Fault Finding - Powershift Gearbox
.
The simplest and best way to fault find the 6 speed gearbox
electrical system, (including the ECU) is by using ShiftMaster
Diagnostics software and a laptop PC. See
Diagnostics
User Guide
. This diagnostics system enables the engineer
to quickly identify faults with specific electrical circuits or
devices. The devices electrical connections, locations and
wire identifications are given in
Electrical Connections -
Powershift Gearbox - 6 Speed
. See also
Section C -
Harness Data
.
If the facilities to use the ShiftMaster Diagnostics software
system are not available, the gearbox and ECU can still be
checked using a conventional multimeter, see
Electrical
Connections - Powershift Gearbox - 6 Speed
. See also
Section C - Harness Data
.
Software Upgrades
From time to time a ShiftMaster ECU ‘Application Software’
upgrades may be made available by JCB Service. If
necessary ‘Application Software’ can be loaded into the
ECU flash memory using a laptop PC and the
ShiftMaster
Flash Programmer
application. This application is part of
the
JCB Service Master
package found on the JCB Service
Technical Information CD’s. The Flash Programmer
application includes comprehensive help files.
Note that the ECU contains 2 sets of software, ‘Application
Software’ and ‘Setup Data’. The ‘Setup Data’ is specific to a
machine variant and can not be changed or replaced.
Renewing The ECU
Before renewing the ECU note the following:
The ShiftMaster ECU is a
non serviceable part
. Any units
returned under warranty found to have been tampered with
will invalidate any claim.
ECU’s are configured at the factory for each machine variant
and are not interchangeable between machines. Although
the part numbers may be the same, the internal software
may not be.
DO NOT interchange ECU’s between
machines
.
Before renewing the ECU carry out all the relevant fault
finding and diagnostics to
confirm ECU failure
. Units
returned under warranty found not to be faulty will invalidate
any claim.
A405370
A
