jcb G20 Operator's Manual page 138

2 Sensor connection faulty
3 Sensor failure
4 Wiring faults
Step Trouble
1 Relay supply voltage fault
2 Relay connection faulty
Step Trouble
1 Wiring fault
2 Network and CAN (Controller
Area Network) resistors faulty
Step Trouble
1 Injector cylinder position and
value fault
2 Injector program fault
3 Electrical connection faulty
Step Trouble
1 HPV (High Pressure Valve)
connection fault
2 Wiring fault
3 Electrical resistance fault
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Check the condition of sensor to harness connection, make
sure the seals are in place, check for signs of corrosion or con-
tamination. Repair/replace as necessary.
If no fault is found, proceed to Step 3.
Check the sensor resistance (see relevant helpfile page). If
sensor is out of specification replace.
If no faults is found, proceed to Step 4.
Check the harness continuity and machine and engine earth
contacts. Repair/replace as necessary.
If no fault found, raise Techweb Helpdesk call.
Table 50. General Relay Fault
Action/Remedy
Perform the relay test routine.
If relay supply voltage is found fault, proceed to Step 2.
If relay supply voltage is OK, raise Techweb Helpdesk Call.
Check the condition of relay to harness connection, make sure
the seals are in place, check for signs of corrosion or contami-
nation. Repair/replace as necessary.
If no fault is found, proceed to Step 3.
Table 51. Electrical Network - CanBus system
Action/Remedy
Check the harness continuity and electrical insolation, re-
pair/replace as necessary.
If no faults is found, proceed to Step 3.
Check the network and CAN resistors, repair as necessary.
If no fault is found proceed to raise Techweb Helpdesk call.
Table 52. Injector Calibration
Action/Remedy
Check that `individual injector corrections' are correctly entered
in ECU. Check the cylinder position and value.
If no faults is found, proceed to Step 3.
Re-flash the injector calibration codes, respecting power down
and up delay and taking care of injector position; erase all the
faults.
If no fault is found proceed to step 4.
Check the knock sensor connection and screw torque, repair
as necessary. Check the ground shield connection of knock
sensor.
If no knock sensor is installed, raise Techweb Helpdesk call.
Table 53. High Pressure Fuel Valve
Action/Remedy
Check the connection of HPV.
If the HPV connection is faulty, repair or replace as necessary.
If no fault is found proceed to step 2.
Check the harness continuity and electrical insolation, re-
pair/replace as necessary.
If no fault is found proceed to step 3.
Measure the HPV electrical resistance, it should be around
2.2Ω at 25°C (77.0°F).
9831/0650-3
Maintenance
Fault-Finding
131