Isuzu 2000 Trooper Workshop Manual page 1092

D DTC P0161 can be cleared by using the Tech 2 "Clear
Info" function or by disconnecting the PCM battery
feed.
Diagnostic Aids
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.
D Damaged harness – Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
display on the Tech 2 while moving connectors and
wiring harnesses related to the sensor. A change in the
display will indicate the location of the fault.
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.
DTC P0161 – HO2S Heater Circuit Bank 2 Sensor 2
Step
1 Was the "On-Board Diagnostic (OBD) System Check"
performed?
2 NOTE: If the engine has just been operating, allow the
engine to cool for at least 15 minutes before
proceeding.
1. Remove the fuel pump relay.
2. Connect a fused jumper at the fuel pump relay
socket, between the battery positive at the relay and
the relay wire that leads to the fuel pump and HO2S
fuses.
3. Ignition "OFF."
4. Install a Tech 2.
5. Ignition "ON," engine "OFF."
6. Monitor the Bank 2 HO2S 2 voltage for several
minutes.
Did the HO2S voltage go from bias voltage to above or
below the specified values?
3 Inspect the fuse for the Bank 2 HO2S 2 ignition feed.
Is the fuse open?
4 1. Ignition "OFF."
2. Raise the vehicle.
3. Disconnect the Bank 2 HO2S 2 electrical connector.
4. Using a test light connected to a known good ground
(do not use Bank 2 HO2S 2 heater ground or Bank 2
HO2S 2 low), probe the ignition feed circuit at the
Bank 2 HO2S 2 electrical connector (PCM harness
side).
Does the test light illuminate?
5 Connect the test light between the Bank 2 HO2S 2
ignition feed and the Bank 2 HO2S 2 heater ground.
Does the test light illuminate?
TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Action
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. The HO2S should be allowed to cool before
performing this test. If the HO2S heater is
functioning, the signal voltage will gradually increase
or decrease as the sensor element warms. If the
heater is not functioning, the HO2S signal will
remain near the 450 mV bias voltage.
4. This ensures that the ignition feed circuit to the
HO2S is not open or shorted. The test light should
be connected to a good chassis ground, in case the
HO2S low or HO2S heater ground circuit is faulty.
5. This checks the HO2S heater ground circuit.
6. This checks for an open or shorted HO2S heater
element.
11.An open HO2S signal or low circuit can cause the
HO2S heater to appear faulty. Check these circuits
before replacing the sensor.
Value(s)
Go to Step 2
—
Above
650 mV or
Below Diagnostic
250 mV
— Go to Step 15
— Go to Step 5
Go to Step 6
—
6E–223
Yes No
Go to OBD
System
Check
Refer to
Aids Go to Step 3
Go to Step 4
Go to Step 7
Go to Step 8