P0128 Thermostat Insufficient Temperrature For Stable Opreation - Isuzu 2000 Trooper Workshop Manual

6E–166
TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

P0128 Thermostat Insufficient temperrature for Stable Opreation

Circuit Description
D The engine coolant temperature (ECT) sensor
thermistor mounted on a coolant crossover pipe at the
front of the engine.
This code determines if system has insufficient
coolant temperatures for stable operation.
Conditions for setting the DTC
D Engine running.
D No IAT, ECT and MAF DTCs set.
D No VSS DTC set.
Warm case(Ambient temperature is between 50°F and
128°F.):
Time for coolant to reach stabillzed closed loop value is
less than 239 sec.
Cold case(Ambient temperature is between 20°F and
50°F.):
Time for coolant to reach stabillzed thermostat
regulation temperature is more than 263 sec.
Action Taken When the DTC Sets
D The PCM will illuminate the malfunction indicator
lamp(MIL) after the second consecutive trip in which
the fault is detected.
D The PCM will store condition which were present when
the DTC was set as Freeze Frame and in the Failure
Records data.
Diagnostic Trouble Code(DTC)
Conditions for Clearing the MIL/DTC
D The PCM will turn the MIL "OFF" on the third
consecutive trip cycle during which the diagnostic has
been run and the fault condtion is no longer present.
D A history DTC P0128 will clear after 40 cosecutive trip
cycle during which the warm up cycles have occurred
without a fault.
D DTC P0128 can be cleared using the Tech 2 "Clear
Info" function or by disconnecting the PCM battery
feed.
Tech 2 "Clear Info" function or by disconnecting
the PCM battery feed.
Diagnostic Aids
An intermittent may be caused by the following:
D Poor connectons.
D Mis routed harness.
D Rubbed through wire insulation.
D Broken wire inside the insulation.
Check for the following conditions:
D Poor connection at PCM–Inspect harness connectors
for backed out terminals,improper mating,broken
locks, improperly formed or damaged terminals,and
poor terminal to wire connection.
D06RY00169