Isuzu 2000 Trooper Workshop Manual page 1077

6E–208
TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
improper mating, broken locks, improperly formed or
damaged terminals, poor terminal-to-wire-connection,
and damaged harness.
D Faulty HO2S heater or heater circuit – With the ignition
"ON," engine "OFF," the HO2S 1 voltage displayed on
the Tech 2 is normally 455-460 mV. A reading over
1000 mV indicates a signal line shorted to voltage. A
reading under 5 mV indicates a signal line shorted to
ground or signal lines shorted together.
disconnect the HO2S and connect a test light between
the HO2S ignition feed and heater ground circuits. If
the test light does not light for 2 seconds when the
ignition is turned on, repair the open ignition feed or
sensor ground circuit as necessary. If the test light
lights and the HO2S signal and low circuits are OK,
replace the HO2S.
D Intermittent test – With the ignition "ON," monitor the
HO2S signal voltage while moving the wiring harness
DTC P0154 –HO2S Circuit Insufficient Activity Bank 2 Sensor 1
Step
1 Was the "On-Board Diagnostic (OBD) System Check"
performed?
2 1. Install the Tech 2.
2. Run the engine at operating temperature.
3. Operate the engine above 1200 RPM for two
minutes.
Does the Tech 2 indicate Bank 2 HO2S 1 voltage
varying outside the specified values?
3 1. Ignition "ON," engine "OFF."
2. Review and record Tech 2 Failure Records data and
note parameters.
3. Operate the vehicle within Failure Records
conditions as noted.
4. Using a Tech 2, monitor "DTC" info for DTC P0154
until the DTC P0154 test runs.
5. Note the test result.
Does the Tech 2 indicate DTC P0154 failed this
ignition?
4 Check for a damaged harness.
Was a problem found?
5 Check for a poor Bank 2 HO2S 1 high and low circuit
terminal connections at the Bank 2 HO2S 1 harness
connector and replace terminal(s) if necessary.
Did any terminals require replacement?
6 Check for a poor Bank 2 HO2S 1 high and low circuit
terminal connections at the PCM and replace
terminal(s) if necessary.
Did the terminal require replacement?
If not,
Action
and related connectors. If the fault is induced, the
HO2S signal voltage will change. This may help isolate
the location of the malfunction.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
3. If the DTC P0154 test passes while the Failure
Records conditions are being duplicated, an
intermittent condition is indicated.
Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help determine how often
the condition that caused the DTC to be set occurs. This
may assist in diagnosing the condition.
Value(s)
Go to Step 2
—
400-500 mV Go to Step 3
— Go to Step 4
— Verify repair
— Verify repair
— Verify repair
Yes No
Go to OBD
System
Check
Go to Step 4
Refer to
Diagnostic
Aids
Go to Step 5
Go to Step 6
Go to Step 7