jcb JS300 Service Manual page 472

Removal and Replacement Guide
The HECU is a reliable and robust component. Before
removing and replacing the HECU carry out all the relevant
diagnostic and fault finding procedures. Most faults are
usually due to damaged wires, connectors or connected
devices such as sensors or solenoids.
3
4
Fig 7.
Removal
The HECU is not a 'bound ECU'.
1 Park the machine and make it safe. Obey the care
and safety procedures. Refer to Section 2,
Maintenance.
2 Disconnect the battery.
3 Disconnect the black harness connector 3 (J2) and
the grey harness connector 4 (J1) at the HECU. Do
not touch the connector pins. Put some tape over the
connectors to protect the pins.
4 Remove four screws 2 and their associated washers.
Replacement
Replacement is the opposite of the removal procedure.
During the replacement procedure do this work also:
C-47
1
2
C128250-C1
9813/5100-1
Section C - Electrics
Hydraulic Electronic Control Unit (HECU)
– Connect the harness connectors at the correct
sockets on the HECU.
– If the HECU is a replacement unit refer to the ECU
K ECU Set-up ( T C-39)
Set-up instructions.
Note: Do not replace the HECU with a unit from another
machine. ECU's may look the same but have different
software installations.
Test Procedures
Use Servicemaster to identify possible faults with the
relevant wiring, connectors or electrical devices. Do not
use a multimeter on the ECU connector pins. Do not touch
the ECU connector pins.
Electronic Controllers
C-47