jcb G20, Operator'S Manual

Page: 140 / 177

Maintenance
Fault-Finding
133 9831/0650-3 133
Check the Individual Injector Corrections and injector connec-
tions. If the problem with C3I or injector connection is evident,
replace/repair as necessary.
2 Injector connection fault
If no fault is found proceed to step 3.
Run the compression test (automatic or manual), if any of the
engine cylinder pressure is not in the limits, repair/replace as
necessary.
4 Engine Cylinder compression
fault
If no fault is found proceed to step 5.
Check the fuel lines for any blockage and contamination.
Clean the fuel lines as necessary.
5 Blocked inlet tubes
If no fault is found proceed to step 6.
6 Injector faulty Swap the injectors with another. Re-write the trim codes. Re-
place/repair as necessary and re-flash the injector calibration
codes.
Table 58. Knock Sensors
Step Trouble Action/Remedy
Check the following sensors and make sure they work correct-
ly:
Knock sensors
Water temperature sensor
Air temperature sensor
Fuel temperature sensor
Barometric pressure sensor (built inside the ECU)
Check the knock sensors connection and screw torque (Check
particularly the ground shield connection). Repair as necessary
and re-enter all injector calibration codes (read then write) in
correct position to reset learned parameters.
1 Sensor connection fault
If no fault is found proceed to step 2.
Check the grounding of knock sensors, repair as necessary. 2 Knock sensors ground fault
If no fault is found proceed to step 3.
3 Wiring fault Check the harness continuity and electrical installation, re-
pair/replace as necessary.
Table 59. Boost Pressure Sensor
Step Trouble Action/Remedy
Disconnect the sensor, check sensor voltage supply at the
harness connector (see relevant sensor helpfile for pin num-
bers or refer to engine electrical schematic). If voltage supply
is faulty, disconnect all other sensor in turn until voltage supply
returns. Replace the faulty sensor.
1 Sensor supply voltage or cali-
bration fault
If sensor supply voltage is OK, proceed to Step 2.
Check the consistency of barometric pressure reading. Verify
the conformity of air inlet circuit:
- Leakage before Turbo
– Air filter
– Valve position using ServiceMaster
– Vane state
Check all the hose connections for air leaks, repair as neces-
sary.
2 Air inlet circuit fault
If no fault is found, raise Techweb Helpdesk call.
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.
3 Sensor connection faulty
If no fault is found, proceed to Step 4.