Isuzu 2000 Trooper Workshop Manual page 1036

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
6E–167
D Damaged harness–Inspect the wiring harness for
damage.
If the harness appears to be OK,observe the ECT
display on the Tech2 while moving connectors and
wiring harnesses related to the sensor.
A change in the display will indicate the location of
the fault.
If DTC P0128 cannot be duplicated, the
information included in the Faillure Records data
can be useful in determined vehicle mileage since
the DTC was last set.
If it is determined that the DTC occurs
intermittently, performing the DTC P0128
Diagnostic Chart may isolate the cause of the
fault.