jcb G20 Operator's Manual page 140

2 Injector connection fault
4 Engine Cylinder compression
fault
5 Blocked inlet tubes
6 Injector faulty
Step Trouble
1 Sensor connection fault
2 Knock sensors ground fault
3 Wiring fault
Step Trouble
1 Sensor supply voltage or cali-
bration fault
2 Air inlet circuit fault
3 Sensor connection faulty
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Check the Individual Injector Corrections and injector connec-
tions. If the problem with C3I or injector connection is evident,
replace/repair as necessary.
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.
If no fault is found proceed to step 5.
Check the fuel lines for any blockage and contamination.
Clean the fuel lines as necessary.
If no fault is found proceed to step 6.
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
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.
If no fault is found proceed to step 2.
Check the grounding of knock sensors, repair as necessary.
If no fault is found proceed to step 3.
Check the harness continuity and electrical installation, re-
pair/replace as necessary.
Table 59. Boost Pressure Sensor
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.
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.
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.
If no fault is found, proceed to Step 4.
9831/0650-3
Maintenance
Fault-Finding
133