Isuzu Amigo / Axiom / Trooper / Rodeo / VehiCross. Manual - part 792

6E–192

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

check EVAP control system components and hoses.
Refer to

Evaporative Emission (EVAP) Control

System.

MAF sensor – The system can go rich if the MAF
sensor signal indicates an engine airflow
measurement that is not correct. Disconnect the MAF
sensor to see if rich condition is corrected. If so,
replace MAF sensor.

Check for leaking fuel pressure regulator diaphragm by
checking vacuum line to regulator for the presence of
fuel. There should be no fuel in the vacuum line.

TP sensor – An intermittent TP sensor output will
cause the system to go rich, due to a false indication
of the engine accelerating.

Shorted Heated Oxygen Sensor (HO2S)– If the HO2S
is internally shorted, the HO2S voltage displayed on
the Tech 2 will be over 1 volt. Try disconnecting the
affected HO2S with the key “ON”, engine “OFF”. If the
displayed HO2S voltage changes from over 1000 mV
to around 450 mV, replace the HO2S. Silicon
contamination of the HO2S can cause a high HO2S
voltage to be indicated. This condition is indicated by
powdery deposit on the portion of the HO2S exposed
to the exhaust stream. If contamination is noticed,
replace the affected HO2S.

Open HO2S Signal Circuit of Faulty HO2S– A poor
connection or open in the HO2S signal circuit can

cause the DTC to set during deceleration fuel mode.
An HO2S which is faulty and not allowing a full voltage
switch between the rich and lean thresholds can also
cause the condition. Operate the vehicle while
monitoring the HO2S voltage with a Tech 2. If the
HO2S is limited within a range between 300 mV to
600 mV, check the HO2S signal circuit wiring and
associated terminal connections.

If none of the above conditions are present, replace the
affected HO2S.

Test Description

Number(s) below refer to the step number(s) on the
Diagnostic Chart.
3. DTC P0152 failing during deceleration fuel cutoff

mode operation may indicate a condition described
in the “Diagnostic Aids” above. If the DTC P0152
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.

DTC P0152 – HO2S Circuit High Voltage Bank 2 Sensor 1

Step

Action

Value(s)

Yes

Was the “On-Board Diagnostic (OBD) System Check”
performed?

—

Go to

Step 2

Go to

OBD

System

Check

1. Install the Tech 2.
2. Engine is at operating temperature.
3. Operate the vehicle within the parameters specified

under “Conditions for Setting the DTC” criteria
included in Diagnostic Support.

4. Using a Tech 2, monitor Bank 2 HO2S 1 voltage.

Does the Bank 2 HO2S 1 voltage remain above the
specified value?

952 mV

(500 mV in

deceleration

fuel cut-off

mode)

Go to

Step 4

Go to

Step 3

1. Ignition “ON”.
2. Review and record Tech 2 Failure Records data.
3. Operate the vehicle within Failure Records

conditions as noted.

4. Using a Tech 2, monitor “DTC” info for DTC P0152

until the DTC P0152 test runs.

5. Note the test result.

Does the Tech 2 indicate DTC P0152 failed this
ignition?

—

Go to

Step 4

Check the

Procedure

Refer to

Diagnostic

Aids

1. Ignition “OFF”.
2. Disconnect Bank 2 HO2S 1.
3. Ignition “ON”.
4. At HO2S Bank 2 Sensor 1 connector (PCM side)

use a DVM to measure voltages at the high and low
signal terminals.

Are the voltages in the specified range?

3-4 V

Go to

Step 5

Go to

Step 6

6E–193

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

DTC P0152 – HO2S Circuit High Voltage Bank 2 Sensor 1

(Cont'd)

Step

Yes

Value(s)

Action

Repair short to voltage in signal circuit.

Is the action complete?

—

Verify repair

—

1. Ignition “ON”, engine“OFF”.
2. At Bank 2 HO2S 1 connector (PCM side) jumper

both the HO2S high and low signal circuits (PCM
side) to ground.

3. Using a Tech 2, monitor Bank 2 HO2S 1 voltage.

Is Bank 2 HO2S 1 voltage below the specified value?

10 mV

Go to

Step 7

Go to

Step 8

1. Disconnect the jumpers to ground from Bank 2

HO2S 1 PCM-side connector.

2. With the HO2S 1 connector disconnected, monitor

Bank 2 HO2S 1 voltage.

Is the Bank 2 HO2S 1 voltage between the specified
values?

425-475 mV

Check the

Procedure

Refer to

Diagnostic

Aids

Go to

Step 8

Replace the PCM.

IMPORTANT: The replacement PCM must be
programmed. Refer to

On-Vehicle Service in

Powertrain Control Module and Sensors for
procedures.

And also refer to latest Service Bulletin.

Check to see if the Latest software is released or not.
And then Down Load the LATEST PROGRAMMED
SOFTWARE to the replacement PCM.

Is the action complete?

—

Verify repair

—

6E–194

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC)

P0153 HO2S Slow Response Bank 2 Sensor 1

D06RY00175

Circuit Description

The powertrain control module (PCM) continuously
monitors the heated oxygen sensor (HO2S) activity for 90
seconds after “closed loop” has been enabled. During the
monitoring period the PCM counts the number of times
that a rich-to-lean and lean-to-rich response is indicated
and adds the amount of time it took to complete all
rich-to-lean transitions and lean-to-rich transitions. With
this information, an average time for rich-to-lean and
lean-to-rich transitions can be determined. If the average
response time of either transition is too slow, a DTC
P0153 will be set.
A lean-to-rich transition is indicated when the HO2S
voltage changes from less than 300 mV to greater than
600 mV. A rich-to-lean transition is indicated when the
HO2S voltage changes from more than 600 mV to less
than 300 mV. An HO2S that responds too slowly is likely
to be faulty and should be replaced.

Conditions for Setting the DTC

No related DTCs.

Engine coolant temperature (ECT) is above 60

(140

F).

The engine is operating in “closed loop”.

Engine has been running for over 60 seconds.

Canister purge duty cycle is above 2%.

Engine speed is between 1500 RPM and 3000 RPM.

Mass air flow is between 18 g/second and 42 g/second.

All above conditions are met for 3 seconds.

90 seconds after “closed loop” has been enabled, Bank
2 HO2S 1 average transition time between 300 mV
and 600 mV is too slow. The lean-to-rich average
transition response time was longer than 94
milliseconds or the rich-to-lean average transition
response time was longer than 105 milliseconds.

Action Taken When the DTC Sets

The PCM will illuminate the malfunction indicator lamp
(MIL) after the second consecutive trip in which the
fault is detected.

The PCM will store conditions which were present
when the DTC set as Freeze Frame and in the Failure
Records data.

“Open loop” fuel control will be in effect.

Conditions for Clearing the MIL/DTC

The PCM will turn the MIL “OFF” on the third
consecutive trip cycle during which the diagnostic has
been run and the fault condition is no longer present.

A history DTC P0153 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P0153 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.

6E–195

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Aids

Check for the following conditions:

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.

Damaged harness – Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
Bank 2 HO2S 1 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.

Test Description

Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. Verifies that the fault is currently present.

3. HO2S transition time, ratio mean volts and switching

DTCs set for multiple sensors indicate probable
contamination. Before replacing the sensors,
isolate and correct the source of the contamination
to avoid damaging the replacement sensors.

DTC P0153 – HO2S Slow Response Bank 2 Sensor 1

Step

Action

Value(s)

Yes

Was the “On-Board Diagnostic (OBD) System Check”
performed?

—

Go to

Step 2

Go to

OBD

System

Check

NOTE: If any DTCs are set, (except P0133, P1133,
P1134, P1153, and/or P1154), refer to those DTCs
before proceeding with this diagnostic chart.

1. Install the Tech 2.
2. Idle the engine at operating temperature.
3. Operate the vehicle within parameters specified

under “Conditions for Setting the DTC” criteria
included in Diagnostic Support.

4. Using a Tech 2, monitor “DTC” info for DTC P0153

until the DTC P0153 test runs.

5. Note the test result.

Does the Tech 2 indicate DTC P0153 failed this
ignition?

—

Go to

Step 3

Check the

Procedure

Refer to

Diagnostic

Aids

Did the Tech 2 also indicate DTC P0153, P1133,
P1134, P1153, and/or P1154 test failed this ignition?

—

Go to

Step 17

Go to

Step 4

Check for leaks at the pipe joints.

Are the joints leaking?

—

Go to

Step 5

Go to

Step 6

Tighten the U-bolt nuts at the leaking joint.

Is your action complete?

—

Go to

Step 2

—

Check for gaskets that are damage or improperly
installed.

Are there damaged or misaligned gaskets?

—

Go to

Step 7

Go to

Step 8

1. Replace the damaged gaskets.
2. Align the connections.
3. Tighten the connections.

Is your action complete?

—

Go to

Step 2

—

Check for loose exhaust flange connections.

Are the flange connections loose?

—

Go to

Step 9

Go to

Step 10

Tighten the stud nuts or bolts to specifications.

Is your action complete?

—

Go to

Step 2

—

Check for burned or corroded exhaust pipes.

Are the exhaust pipes burned or corroded?

—

Go to

Step 11

Go to

Step 12

Content .. 790 791 792 793 ..